US20160030624A1

US20160030624A1 - Methods and compositions for wound healing

Info

Publication number: US20160030624A1
Application number: US14/882,913
Authority: US
Inventors: Nicholas L. Abbott; Ankit Agarwal; Christopher J. Murphy; Jonathan F. McAnulty
Original assignee: IMBED BIOSCIENCES Inc
Current assignee: IMBED BIOSCIENCES Inc
Priority date: 2008-01-30
Filing date: 2015-10-14
Publication date: 2016-02-04
Also published as: WO2011100425A2; US9174839B2; WO2011100425A3; EP2533772A2; US20110189287A1; EP2533772B1; EP2533772A4

Abstract

The present invention relates to methods and compositions for wound healing. In particular, the present invention relates to promoting and enhancing wound healing by utilizing cross-linker covalent modification molecules to attach and deliver wound active agents to a wound. In addition, the present invention provides methods and compositions utilizing oppositely charged polyelectrolytes to form a polyelectrolyte layer on a wound surface. The invention further relates to incorporating wound active agents into a polyelectrolyte layer for delivery to a wound.

Description

This application is a continuation of U.S. patent application Ser. No. 13/024,856, filed Feb. 10, 2011, which claims the benefit of U.S. Prov. Appl. 61/303,414, filed Feb. 10, 2010, and is a continuation-in-part of U.S. patent application Ser. No. 12/363,044, filed Jan. 30, 2009, which claims the benefit of U.S. Prov. Appl. 61/024,725, filed Jan. 30, 2008, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to methods and compositions for the modulation of wound healing. In particular, the present invention relates to promoting and enhancing wound healing by changing the intrinsic chemical composition and/or physical features of the wound bed.

BACKGROUND OF THE INVENTION

The primary goal in the treatment of wounds is to achieve wound closure. Open cutaneous wounds represent one major category of wounds and include burn wounds, wounds resulting from chemical (especially alkali) burns, wounds from physical trauma, neuropathic ulcers, pressure sores, venous stasis ulcers, and diabetic ulcers. Open cutaneous wounds routinely heal by a process which comprises six major components: i) inflammation, ii) fibroblast proliferation, iii) blood vessel proliferation, iv) connective tissue synthesis, v) epithelialization, and vi) wound contraction. Wound healing is impaired when these components, either individually or as a whole, do not function properly. Numerous factors can affect wound healing, including but not limited to malnutrition, systemic debility due to a variety of causes, wound infection, local lack of progenitor cells, local and/or systemic pharmacological agents (e.g., numerous chemotherapeutic agents, actinomycin and steroids), repeated local trauma, diabetes and other endocrine/metabolic diseases (e.g., Cushing's disease), and advanced age (Hunt and Goodson, 1988, Current Surgical Diagnosis & Treatment, Appleton & Lange, pp. 86-98). Additionally, wounds that are extensive in size, regardless of the initiating cause, present special challenges due to the large surface area that must be re-epithelialized to re-establish surface integrity.
Delayed wound healing causes substantial morbidity in subjects with diabetes. Diabetes mellitus is a chronic disorder of glucose metabolism and homeostasis that damages many organs. It is the eighth leading cause of death in the United States (Harris et al., 1987, Diabetes 36:523). In persons with diabetes, vascular disease, neuropathy, infections, and recurrent trauma predispose the extremities, especially the foot, to pathologic changes. These pathological changes can ultimately lead to chronic ulceration, which may necessitate amputation. Chronic wounds and wounds with pathological or dysregulated healing represent a major health burden and drain on health care resources. Chronic wounds have major impacts on the physical and mental health, productivity, morbidity, mortality and cost of care for affected individuals. The most common types of chronic wounds are caused by systemic diseases such as diabetes, vascular problems such as venous hypertension and by immobility-induced pressure sores; accounting for 70% of all chronic wounds. Statistics on the prevalence of chronic wounds varies, however studies report that 0.2% to 1% of the population suffer from venous ulcers, 0.5% from pressure ulcers, and 5% to 10% of people with diabetes experience neuropathic ulcers. The economic impact of chronic wounds for these conditions alone in the United States has been estimated to be well over $15 billion, annually. With the population growing older, cases of diabetes mellitus will increase as will the magnitude of the problem associated with chronic wounds in these patients.
Normal wound healing is an enormously complex process involving the coordinated interplay between fibroblasts, vascular cells, extracellular matrix and epithelial cells to result in a seamless progression through an inflammatory reaction, wound repair, contracture and coverage by an epithelial barrier. However, in many patients, due to either the local wound environment or systemic disease or other factors, the wound healing processes can become asynchronous (i.e., loss of connectivity with triggering mechanisms associated with prior cellular events) and are unable to progress to closure, resulting in a chronic ulcer.
Wounds that do not readily heal can cause the subject considerable physical, emotional, and social distress as well as great financial expense (Richey et al., 1989, Annals of Plastic Surgery 23:159). Indeed, wounds that fail to heal properly and become infected may require excision of the affected tissue. A number of treatment modalities have been developed as scientists' basic understanding of wounds and wound healing mechanisms has progressed. The most commonly used conventional modality to assist in wound healing involves the use of wound dressings. In the 1960s, a major breakthrough in wound care occurred when it was discovered that wound healing with moist, occlusive dressings was, generally speaking, more effective than the use of dry, non-occlusive dressings (Winter, 1962, Nature 193:293). Today, numerous types of dressings are routinely used, including films (e.g., polyurethane films), hydrocolloids (hydrophilic colloidal particles bound to polyurethane foam), hydrogels (crosslinked polymers containing about at least 60% water), foams (hydrophilic or hydrophobic), calcium alginates (nonwoven composites of fibers from calcium alginate), and cellophane (cellulose with a plasticizer) (Kannon and Garrett, 1995, Dermatol. Surg. 21:583; Davies, 1983, Burns 10:94). Unfortunately, certain types of wounds (e.g., diabetic ulcers, pressure sores) and the wounds of certain subjects (e.g., recipients of exogenous corticosteroids) do not heal in a timely manner (or at all) with the use of such dressings.
Several pharmaceutical modalities have also been utilized in an attempt to improve wound healing. For example, some practitioners have utilized treatment regimens involving zinc sulfate. However, the efficacy of these regimens has been primarily attributed to their reversal of the effects of sub-normal serum zinc levels (e.g., decreased host resistance and altered intracellular bactericidal activity) (Riley, 1981, Am. Fam. Physician 24:107). While other vitamin and mineral deficiencies have also been associated with decreased wound healing (e.g., deficiencies of vitamins A, C and D; and calcium, magnesium, copper, and iron), there is no strong evidence that increasing the serum levels of these substances above their normal levels actually enhances wound healing. Thus, except in very limited circumstances, the promotion of wound healing with these agents has met with little success.
Current clinical approaches used to promote healing in dysregulated wounds include protection of the wound bed from mechanical trauma (e.g. splinting, bandaging), meticulous control of surface microbial burden (antibiotics, antimicrobial peptides, bacteriophages, antiseptics and other antimicrobial compounds that broadly inhibit wound pathogens (e.g., silver sulfadiazine) combined with topical application of soluble cytoactive factors (e.g. growth factors exemplified by but not limited to epidermal growth factor-EGF, exogenous extracellular matrix constituents such as fibronectin), surgical excision of the wound margin or entire bed and surgical placement of tissue flaps and/or autografts, allografts and xenografts. All of these approaches fall short of promoting optimal healing conditions in many of the most challenging wounds. It is likely that a major contributing factor to the failure of these traditional approaches is the fact that they do not alter the intrinsic chemistry/structure of the wound bed itself that has been shown in many cases to contribute significantly to their persistence. Additionally, the historical use of a single factor or set of factors to treat all wounds often falls short due to the great heterogeneity found in wound beds themselves and the complex environment of the wound itself containing a community of signaling molecules that frequently modulate the activity of individual molecules.
Of broad-spectrum bactericidal agents, silver is considered particularly favorable because the likelihood of developing bacterial resistance to silver is believed to be very low; therefore, it can be employed as a bactericidal agent continuously. However, currently available methods of applying silver as a bactericidal agent for wound treatment are inadequate. For example, 0.5% silver nitrate solution is a standard and popular agent for topical burn wound therapy, providing a beneficial effect in decreasing wound surface inflammation. However, while such formulations have a high concentration of silver, there is no residual activity, necessitating frequent applications (e.g., up to 12 times a day) which poses a severe logistical burden in clinical settings. Silver ions released through use of 0.5% silver nitrate solution become rapidly inactive through formation of chemical complexes by chloride within 2 hours. Frequent dressings also result in large excesses of silver being delivered to the wound, causing wound-discoloration and toxic effects (Dunn et al., 2004, Burns 30(supplement 1):S1; herein incorporated by reference in its entirety). Additionally, nitrate is toxic to wounds and to mammalian cells. The reduction of nitrate to nitrite further causes oxidant-induced damage to cells, which is cited as the most likely reason for the impaired re-epithelialization with use of silver nitrate solution in partial thickness burns or donor sites.
Silver compounds such as silver sulfadiazine in cream formulations (e.g., Flammazine®, Silvadene®) have also been used for wound treatment. However, such formulations also have limited residual activity and have to be applied twice a day. Bacterial resistance does develop to these formulations, and, impaired re-epithelialization has also been observed. Bone marrow toxicity has been observed with silver sulfadiazine, primarily due to its propylene glycol component.
Additionally, in some methods, silver itself is incorporated into the dressing instead of being applied as a separate formulation. Controlled and prolonged release of silver to the wound allows dressings to be changed less frequently. However, dressings have to be impregnated with large amount of silver, which results in cytotoxicity to mammalian cells. Silver released from a commercially available wound-dressing (Acticoat™) containing nanocrystalline silver (Dunn et al., 2004, Burns 30(supplement 1):S1; herein incorporated by reference in its entirety) is toxic to in vitro monolayer cell cultures of keratinocytes and fibroblasts (Poon et al., 2004, Burns 30:140; Trop et al., 2006, J. Trauma 60:648; each herein incorporated by reference in its entirety). The complex nature of pathologic wounds, and the lack of significant clinical progress based on current therapies, indicates the urgent need for new and unconventional approaches. What is needed is are safe, effective, and interactive means for enhancing the healing of chronic and severe wounds. The methods should be adaptable without regard to the type of wound, or the nature of the patient population, to which the subject belongs.

SUMMARY OF THE INVENTION

The present invention relates to methods and compositions for the modulation of wound healing. In particular, the present invention relates to promoting and enhancing wound healing by changing the intrinsic chemical composition and/or physical attributes of the wound bed. Accordingly, in some embodiments the present invention provides formulations that alter the physical attributes (compliance, topography, charge), as well as cross-linker covalent modification molecules to attach and deliver antimicrobial compounds as well as extracellular matrices and other scaffolds and cytoactive agents to a wound. In addition, the present invention provides methods and compositions utilizing oppositely charged polyelectrolytes to form a polyelectrolyte layer on a wound surface. The invention further relates to the incorporation of non-charged polymers into the wound bed via interactions such as but not limited to hydrogen bonding. The scope of the invention includes incorporation of nanoparticles and microparticles into the wound bed to engineer the physical characteristics and chemical composition of the wound bed. The invention further relates to incorporating wound active agents into a polyelectrolyte layer, nanoparticle or microparticle for delivery to a wound. In some embodiments, the present invention provides formulations that promote a favorable and stable pH, surface charge, surface energy, osmotic environment, surface functionalities that enhance galvano and magneto positive effects on wound healing, supply of nitric oxide, provide energy sources for cells and/or provide a balance of MMP/other peptidase/protease activity. The present invention further relates to providing compositions, methods, and kits comprising selectively toxic wound active agents that are highly bactericidal but that support growth and viability of mammalian cells (e.g., keratinocytes, neurons, vascular endothelial cells and fibroblasts cells). In preferred embodiments, the wound active agent is silver, including but not limited to silver nanoparticles. In particularly preferred embodiments, the silver loading of some embodiments of the present invention is between 0.35 and 0.4 μg/cm². Polyelectrolyte thin films of the present invention comprising silver (e.g., silver nanoparticles) find use in the treatment of wounds and the prevention of infection, including but not limited to as coatings on devices that come partially, directly, indirectly, or completely in contact with the body of a subject (e.g., a human patient).
In one embodiment, the compositions and methods of the present invention provide approaches to promote healing in pathologic wounds by altering the surface chemistry and structure of the pathologic wound bed itself so as to ultimately enable differential modulation of key cellular elements customizable to the specific patient's health wound type and anatomic location in a subject.
In one embodiment, the present invention provides for the covalent immobilization of factors to the wound bed. In some embodiments, the present invention provides methods of treatment, comprising providing a subject having a wound, at least one covalent modification agent and at least one wound active agent, and contacting the wound with the at least one covalent modification agent and the at least one wound active agent under conditions such that the at least one wound active agent is covalently attached to the wound. In some embodiments, the subject is a human. In other embodiments, the subject is a non-human vertebrate. In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker. In other embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker. For example, in some embodiments, the homobifunctional cross-linker is an N-hydroxysuccinimidyl ester (e.g., including, but not limited to, disuccinimidyl ester, dithiobis(succinimidylpropionate), 3,3′-dithiobis(sulfosuccinimidylpropionate), disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, disuccinimidyl tartarate, disulfosuccinimidyl tartarate, bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone, bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone, ethylene glycolbis(succinimidylsuccinate), ethylene glycolbis(sulfosuccinimidylsuccinate), disuccinimidyl glutarate, and N,N′-disuccinimidylcarbonate). In some embodiments, the homobifunctional cross-linker is at a concentration between 1 nanomolar and 10 millimolar. In some preferred embodiments, the homobifunctional cross-linker is at a concentration between 10 micromolar and 1 millimolar. In other embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker (e.g., including, but not limited to, N-succinimidyl 3-(2-pyridyldithio)propionate, succinimidyl 6-(3-[2-pyridyldithio]-propionamido)hexanoate, sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido)hexanoate, succinimidyloxycarbonyl-α-methyl-α-(2-pyridyldithio)toluene, sulfosuccinimidyl-6-[α-methyl-α-(2-pyridyldithio)toluamido]hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, m-maleimidobenzoyl-N-hydroxysuccinimide ester, m-maleimidobenzoyl-N-hydroxy-sulfosuccinimide ester, N-succinimidyl(4-iodoacetyl)aminobenzoate, sulfo-succinimidyl(4-iodoacetyl)aminobenzoate, succinimidyl-4-(p-maleimidophenyl)butyrate, sulfosuccinimidyl-4-(p-maleimidophenyl)butyrate, N-(γ-maleimidobutyryloxy)succinimide ester, N-(γ-maleimidobutyryloxy)sulfosuccinimide ester, succinimidyl 6-((iodoacetyl)amino)hexanoate, succinimidyl 6-(6-(((4-iodoacetyl)amino)hexanoyl)amino)hexanoate, succinimidyl 4-(((iodoacetyl)amino)methyl)cyclohexane-1-carboxylate, succinimidyl 6-((((4-iodoacetyl)amino)methyl)cyclohexane-1-carbonyl)amino)-hexanoate, and p-nitrophenyl iodoacetate). In some embodiments, the heterobifunctional cross-linker is modified with functional groups, rendering it soluble in aqueous solvents for delivery as an aqueous solution. Furthermore, in some embodiments, the aqueous solution contains additives (e.g., including, but not limited to, surfactants and block copolymers). In other embodiments, a multiplicity of heterobifunctional cross-linkers can be attached to a molecule, polymer or particle to serve as the cross-linking agent. In other embodiments, the heterobifunctional cross-linker is dissolved in an organic solvent (e.g., including, but not limited to, dimethyl sulfoxide). In some embodiments, the at least one wound active agent includes, but is not limited to, trophic factors, extracellular matrices, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents, buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents. In some embodiments, the at least one wound active agent contains one or more free —SH groups.
The present invention also provides a kit for treating a subject having a wound, comprising at least one covalent modification agent, at least one wound active agent, and instructions for using the kit to covalently link the at least one wound active agent to the wound. In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker. In some embodiments, the homobifunctional cross-linker is an N-hydroxysuccinimidyl ester (e.g., including, but not limited to, disuccinimidyl ester, dithiobis(succinimidylpropionate), 3,3′-dithiobis(sulfosuccinimidylpropionate), disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, disuccinimidyl tartarate, disulfosuccinimidyl tartarate, bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone, bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone, ethylene glycolbis(succinimidylsuccinate), ethylene glycolbis(sulfosuccinimidylsuccinate), disuccinimidyl glutarate, and N,N′-disuccinimidylcarbonate). In some embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker (e.g., including, but not limited to, N-succinimidyl 3-(2-pyridyldithio)propionate, succinimidyl 6-(3-[2-pyridyldithio]-propionamido)hexanoate, sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido)hexanoate, succinimidyloxycarbonyl-α-methyl-α-(2-pyridyldithio)toluene, sulfosuccinimidyl-6-[α-methyl-α-(2-pyridyldithio)toluamido]hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, m-maleimidobenzoyl-N-hydroxysuccinimide ester, m-maleimidobenzoyl-N-hydroxy-sulfosuccinimide ester, N-succinimidyl(4-iodoacetyl)aminobenzoate, sulfo-succinimidyl(4-iodoacetyl)aminobenzoate, succinimidyl-4-(p-maleimidophenyl)butyrate, sulfosuccinimidyl-4-(p-maleimidophenyl)butyrate, N-(γ-maleimidobutyryloxy)succinimide ester, N-(γ-maleimidobutyryloxy)sulfosuccinimide ester, succinimidyl 6-((iodoacetyl)amino)hexanoate, succinimidyl 6-(6-(((4-iodoacetyl)amino)hexanoyl)amino)hexanoate, succinimidyl 4-(((iodoacetyl)amino)methyl)cyclohexane-1-carboxylate, succinimidyl 6-((((4-iodoacetyl)amino)methyl)cyclohexane-1-carbonyl)amino)-hexanoate, and p-nitrophenyl iodoacetate). In some embodiments, the at least one wound active agent includes, but is not limited to, trophic factors (including polypetide growth factors, neuropeptides, neurotrophins, extracellular matrices and their individual native constituents (exemplified by but not limited to laminin, fibronectin, vitronectin, collagens, also select amino acid sequences found in these proteins known to promote cell behaviors favorable to wound healing e.g., integrin binding sequences exemplified by but not limited to RGD, EILDV, VCAM-1 and their recombined or synthetic analogs, enzymes, enzyme inhibitors, polypeptides, antimicrobial peptides (exemplified by but not limited to defensins, magaignins, cathelocidins, bactenicin) anti-infective agents including silver containing compounds (e.g., ionic silver, elemental silver, silver nanoparticles, and formulations thereof), buffering agents, vitamins and minerals, compounds that promote generation/stabilization of nitic oxide, energy sources for cells, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents. In other embodiments the kits include small interfering RNAs (siRNAs—also referred to as micro RNAs) that are capable of promoting cellular behaviors conducive to the wound healing process. In other embodiments, the kits include compounds that promote/stabilize a favorable pH, osmotic environment, surface energy, surface charge, surface functionalities that enhance galvano and magneto positive effects on wound healing, or balance of MMP/other peptidase/protease activity.
In some embodiments, the present invention provides a method of treatment, comprising providing a subject having a wound, at least one cationic polyelectrolyte, at least one anionic polyelectrolyte, at least one covalent modification agent, and at least one wound active agent, and contacting the wound with the at least one cationic and the at least one anionic polyelectrolytes, the at least one covalent modification agent, and the at least one wound active agent so that the at least one wound active agent is covalently linked to the wound by incorporation into a polyelectrolyte layer formed by the at least one cationic and the at least one anionic polyelectrolytes. In some preferred embodiments, the polyelectrolytes are sequentially and repeatedly layered on the wound, then the at least one covalent modification agent and the at least one wound active agent are added. In some embodiments, the at least one cationic polyelectrolyte (e.g., including, but not limited to, poly(L-lysine), poly(ethylene imine), and poly(allylamine hydrochloride and dendrimers and multi-armed polymers that present multiple amine groups) is the top layer of the polyelectrolyte layers. Furthermore, in some embodiments, the at least one cationic polyelectrolyte harbors a primary amine group which allows attachment of the at least one covalent modification agent to the at least one cationic polyelectrolyte. For example, in some preferred embodiments, the at least one cationic polyelectrolyte is polylysine and the at least one anionic polyelectrolyte is polyglutamic acid. In some embodiments, the at least one anionic polyelectrolyte (e.g., including, but not limited to, poly(L-glutamic acid), poly(sodium 4-styrenesulfonate), poly(acrylic acid), poly(maleic acid-co-propylene), hyaluronic acid, chondroitin, and poly(vinyl sulfate)) is the top layer of the polyelectrolyte layers. In a preferred embodiment, the at least one anionic polyelectrolyte is polyglutamic acid. In some embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker (e.g., including, but not limited to, N-succinimidyl 3-(2-pyridyldithio)propionate, succinimidyl 6-(3-[2-pyridyldithio]-propionamido)hexanoate, sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido)hexanoate, succinimidyloxycarbonyl-α-methyl-α-(2-pyridyldithio)toluene, sulfosuccinimidyl-6-[α-methyl-α-(2-pyridyldithio)toluamido]hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, m-maleimidobenzoyl-N-hydroxysuccinimide ester, m-maleimidobenzoyl-N-hydroxy-sulfosuccinimide ester, N-succinimidyl(4-iodoacetyl)aminobenzoate, sulfo-succinimidyl(4-iodoacetyl)aminobenzoate, succinimidyl-4-(p-maleimidophenyl)butyrate, sulfosuccinimidyl-4-(p-maleimidophenyl)butyrate, N-(γ-maleimidobutyryloxy)succinimide ester, N-(γ-maleimidobutyryloxy)sulfosuccinimide ester, succinimidyl 6-((iodoacetyl)amino)hexanoate, succinimidyl 6-(6-(((4-iodoacetyl)amino)hexanoyl)amino)hexanoate, succinimidyl 4-(((iodoacetyl)amino)methyl)cyclohexane-1-carboxylate, succinimidyl 6-((((4-iodoacetyl)amino)methyl)cyclohexane-1-carbonyl)amino)-hexanoate, and p-nitrophenyl iodoacetate). In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker. In some embodiments, the homobifunctional cross-linker is an N-hydroxysuccinimidyl ester (e.g., including, but not limited to, disuccinimidyl ester, dithiobis(succinimidylpropionate), 3,3′-dithiobis(sulfosuccinimidylpropionate), disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, disuccinimidyl tartarate, disulfosuccinimidyl tartarate, bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone, bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone, ethylene glycolbis(succinimidylsuccinate), ethylene glycolbis(sulfosuccinimidylsuccinate), disuccinimidyl glutarate, and N,N′-disuccinimidylcarbonate). In some embodiments, the at least one covalent modification agent can be at a concentration between 1 nanomolar and 10 millimolar. In some preferred embodiments, the at least one covalent modification agent is at a concentration between 10 micromolar to 1 millimolar. In some preferred embodiments, the at least one covalent modification agent is bis(sulfosuccinimidyl)suberate (for example, in aqueous solution at a concentration between 1 nM and 10 mM). In some embodiments, the at least one covalent modification agent comprises N-hydroxysuccinimidyl ester. In some preferred embodiments, the at least one wound active agent contains the peptide sequence gly-arg-gly-asp-ser-pro-lys.
In some embodiments, a first at least one anionic or cationic polyelectrolyte is contacted with the at least one covalent modification agent and the at least one wound active agent before contacting with the wound bed and oppositely charged at least one cationic or anionic polyelectrolyte. In some preferred embodiments, the first at least one anionic polyelectrolyte is polyglutamic acid, the at least one covalent modification agent is N-hydroxysuccinimidyl ester, and the at least one wound active agent contains a primary amine (e.g., including, but not limited to, the peptide sequence gly-arg-gly-asp-ser-pro-lys). In some preferred embodiments, the first at least one cationic polyelectrolyte is polylysine, the at least one covalent modification agent is N-succinimidyl 3-(2-pyridyldithio)propionate, and the at least one wound active agent contains the peptide sequence gly-arg-gly-asp-ser-pro-cys.
The present invention further provides kits for treating a subject having a wound, comprising at least one cationic polyelectrolyte, at least one anionic polyelectrolyte, at least one covalent modification agent, at least one wound active agent; and instructions for using the kit to covalently link the at least one wound active agent to the wound by incorporation into a polyelectrolyte layer that is formed by the at least one cationic and anionic polyelectrolytes. In some embodiments, the incorporation of the at least one wound active agent is achieved by sequential and repeated layering of the polyelectrolytes, followed by addition of the at least one covalent modification agent and the at least one wound active agent. In other embodiments, a first at least one anionic or cationic polyelectrolyte is contacted with the at least one covalent modification agent and the at least one wound active agent before contacting with the wound bed and oppositely charged at least one cationic or anionic polyelectrolyte. In some embodiments, the at least one cationic polyelectrolyte includes, but is not limited to, poly(L-lysine), poly(ethylene imine), and poly(allylamine hydrochloride). In some embodiments, the at least one anionic polyelectrolyte includes, but is not limited to, poly(L-glutamic acid), poly(sodium 4-styrenesulfonate), poly(acrylic acid), poly(maleic acid-co-propylene), and poly(vinyl sulfate). In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker. In some embodiments, the homobifunctional cross-linker is an N-hydroxysuccinimidyl ester (e.g., including, but not limited to, disuccinimidyl ester, dithiobis(succinimidylpropionate), 3,3′-dithiobis(sulfosuccinimidylpropionate), disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, disuccinimidyl tartarate, disulfosuccinimidyl tartarate, bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone, bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone, ethylene glycolbis(succinimidylsuccinate), ethylene glycolbis(sulfosuccinimidylsuccinate), disuccinimidyl glutarate, and N,N′-disuccinimidylcarbonate). In other embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker (e.g., including, but not limited to, N-succinimidyl 3-(2-pyridyldithio)propionate, succinimidyl 6-(3-[2-pyridyldithio]-propionamido)hexanoate, sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido)hexanoate, succinimidyloxycarbonyl-α-methyl-α-(2-pyridyldithio)toluene, sulfosuccinimidyl-6-[α-methyl-α-(2-pyridyldithio)toluamido]hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, m-maleimidobenzoyl-N-hydroxysuccinimide ester, m-maleimidobenzoyl-N-hydroxy-sulfosuccinimide ester, N-succinimidyl(4-iodoacetyl)aminobenzoate, sulfo-succinimidyl(4-iodoacetyl)aminobenzoate, succinimidyl-4-(p-maleimidophenyl)butyrate, sulfosuccinimidyl-4-(p-maleimidophenyl)butyrate, N-(γ-maleimidobutyryloxy)succinimide ester, N-(γ-maleimidobutyryloxy)sulfosuccinimide ester, succinimidyl 6-((iodoacetyl)amino)hexanoate, succinimidyl 6-(6-(((4-iodoacetyl)amino)hexanoyl)amino)hexanoate, succinimidyl 4-(((iodoacetyl)amino)methyl)cyclohexane-1-carboxylate, succinimidyl 6-((((4-iodoacetyl)amino)methyl)cyclohexane-1-carbonyl)amino)-hexanoate, and p-nitrophenyl iodoacetate). In some embodiments, the at least one wound active agent includes, but is not limited to, trophic factors, extracellular matrices, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents (including but not limited to silver (e.g., ionic silver, elemental silver, silver nanoparticles, and formulations thereof)), buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents.
The present invention also provides a method of treatment, comprising providing a subject having a wound, at least one cationic polyelectrolyte, at least one anionic polyelectrolyte, at least one DNA delivery agent, and at least one DNA species, and contacting the wound with the at least one cationic polyelectrolyte, the at least one anionic polyelectrolyte, the at least one DNA delivery agent, and the at least one DNA species under conditions such that the at least one DNA species is delivered to the wound. In some preferred embodiments, the at least one DNA species includes, but is not limited to, DNA encoding vascular endothelial growth factor and/or epidermal growth factor. In some preferred embodiments, the at least one cationic polyelectrolyte is polylysine. In some embodiments, the method further comprises contacting the wound with an additional wound active agent (including but not limited to an anti-infective agent (e.g., ionic silver, elemental silver, silver nanoparticles, and formulations thereof.)
The present invention further provides a kit for treating a subject having a wound, comprising: at least one cationic polyelectrolyte, at least one anionic polyelectrolyte, at least one DNA delivery agent, at least one DNA species, and instructions for using the kit to deliver the at least one DNA species to the wound using the at least one DNA delivery agent and a polyelectrolyte layer formed by the at least one cationic and anionic polyelectrolytes. In some embodiments, the kit further comprises an additional wound active agent (including but not limited to an anti-infective agent (e.g., ionic silver, elemental silver, silver nanoparticles, and formulations thereof.)
The present invention also provides a method of treatment, comprising providing a subject having a wound, a cationic and anionic polyelectrolyte mixture, a deprotection agent, at least one covalent modification agent, and at least one wound active agent; contacting the wound with the polyelectrolyte mixture to form a polyelectrolyte layer on the wound; applying the deprotection agent to the polyelectrolyte layer to form a deprotected polyelectrolyte layer; applying the at least one covalent modification agent to the deprotected polyelectrolyte layer to form a modified deprotected polyelectrolyte layer; and applying the at least one wound active agent to the modified deprotected polyelectrolyte layer under conditions such that the at least one wound active agent is covalently attached to the wound. In some preferred embodiments, the anionic and cationic polyelectrolyte mixture is made up of polylactic acid and poly(epsilon-CBZ-L-lysine), blended at an 80:20 ratio. In some embodiments, the deprotection occurs by acid hydrolysis. In some embodiments, the at least one covalent modification agent is SP3. The present invention also provides a composition comprising a deprotected polyelectrolyte, functionalized with at least one covalent modification agent containing an active group that is exposable to at least one wound active agent. In some preferred embodiments, the deprotected polyelectrolyte is comprised of polylactic acid and poly(epsilon-CBZ-L-lysine), blended at an 80:20 ratio. In a preferred embodiment, the at least one covalent modification agent is SP3.
The present invention also provides a method of treatment, comprising providing a subject having a wound, a cationic and anionic polyelectrolyte mixture, a deprotection agent, at least one covalent modification agent, a first polypeptide, and at least one wound active agent linked to a second polypeptide; contacting the wound with the polyelectrolyte mixture to form a polyelectrolyte layer on the wound; applying the deprotection agent to the polyelectrolyte layer to form a deprotected polyelectrolyte layer; applying the at least one covalent modification agent to the deprotected polyelectrolyte layer to form a modified deprotected polyelectrolyte layer; applying the first polypeptide to the modified deprotected polyelectrolyte layer to covalently link the first polypeptide to the modified deprotected polyelectrolyte layer; and applying the at least one wound active agent linked to the second polypeptide to the modified deprotected polyelectrolyte layer covalently linked to the first polypeptide, under conditions such that the at least one wound active agent is attached to the wound by specific protein binding between the first polypeptide and the second polypeptide. In some preferred embodiments, the specific protein binding occurs between biotin and a polypeptide (e.g., including, but not limited to, avidin, neutravidin, and streptavidin). In other preferred embodiments, the specific protein binding occurs between glutathione-S-transferase and glutathione. In yet other preferred embodiments, the specific protein binding occurs between nickel-nitrilotriacetic acid and polyhistidine. In some embodiments, the at least one covalent modification agent is SP3.
The present invention further provides a composition comprising a deprotected polyelectrolyte functionalized with at least one covalent modification agent linked to a first polypeptide that interacts by specific binding with a second polypeptide linked to at least one wound active agent. In some preferred embodiments, the specific binding occurs between biotin and a polypeptide (e.g., including, but not limited to, avidin, neutravidin, and streptavidin). In other preferred embodiments, the specific binding occurs between glutathione-S-transferase and glutathione. In still other preferred embodiments, the specific protein binding occurs between nickel-nitrilotriacetic acid and polyhistidine.
The present invention also provides a method of treatment, comprising providing a subject having a wound, a cationic and anionic polyelectrolyte mixture, a deprotection agent, at least one covalent modification agent, at least one molecule containing an azide group, and at least one wound active agent containing an alkyne group; contacting the wound with the polyelectrolyte mixture to form a polyelectrolyte layer on the wound; applying the deprotection agent to the polyelectrolyte layer to form a deprotected polyelectrolyte layer; applying the at least one covalent modification agent to the deprotected polyelectrolyte layer to form a modified deprotected polyelectrolyte layer; applying the at least one molecule containing an azide group to the modified deprotected polyelectrolyte layer to covalently link the at least one molecule containing an azide group to the modified deprotected polyelectrolyte layer; and applying the at least one wound active agent containing an alkyne group to the modified deprotected polyelectrolyte layer covalently linked to the at least one molecule containing an azide group, so that the at least one wound active agent is attached to the wound by click chemistry. In some preferred embodiments, the at least one molecule containing an azide group has the formula H₂N(CH₂CH₂O)₂N₃. In some preferred embodiments, the at least one wound active agent is L-propargylglycine. In some preferred embodiments, the reaction is carried out in the presence of Cu(I).
The present invention further provides a composition comprising a deprotected polyelectrolyte functionalized with at least one covalent modification agent linked to at least one molecule containing an azide group that is attached by click chemistry to at least one wound active agent containing an alkyne group.
The present invention further provides a kit for treating a subject having a wound, comprising a cationic and anionic polyelectrolyte mixture, a deprotection agent, at least one covalent modification agent, at least one wound active agent, and instructions for using the kit to covalently link the at least one wound active agent to the wound by deprotection of the polyelectrolyte mixture contacted to the wound, followed by addition of the at least one covalent modification agent and the at least one wound active agent. In some preferred embodiments, the polyelectrolyte mixture comprises polylactic acid and poly(epsilon-CBZ-L-lysine). In some preferred embodiments, the deprotection agent causes deprotection by acid hydrolysis of the polyelectrolyte mixture. In some preferred embodiments, the at least one covalent modification agent is SP3. In some embodiments, the kit also contains a first and a second polypeptide that interact with each other by specific protein binding. In some preferred embodiments, the first polypeptide is linked to either the at least one covalent modification agent or the at least one wound active agent and the second polypeptide is linked to the other at least one covalent modification agent or the at least one wound active agent. In some preferred embodiments, the first polypeptide is biotin and the second polypeptide is avidin, neutravidin, or streptavidin. In some other preferred embodiments, the first polypeptide is glutathione-S-transferase and the second polypeptide is glutathione. In still other preferred embodiments, the first polypeptide is nickel-nitrilotriacetic acid and the second polypeptide is polyhistidine. In some embodiments, the kit contains at least one molecule containing an azide group that is attached to the polyelectrolyte mixture after deprotection so that at least one wound active agent containing an alkyne group can be attached to the wound by click chemistry.
The present invention further provides a method of treatment, comprising providing a subject having a wound, at least one cationic polyelectrolyte, at least one anionic polyelectrolyte, at least one modifying agent, and at least one wound active agent containing an amino terminal cysteine residue; and contacting the wound with the polyelectrolytes, the at least one modifying agent and the at least one wound active agent so that the at least one wound active agent is attached to the wound by native chemical ligation. In some preferred embodiments, the polyelectrolytes are sequentially and repeatedly layered on the wound. In some embodiments, the at least one anionic polyelectrolyte (e.g., including, but not limited to, polyglutamic acid) is the top layer of the polyelectrolyte layers. In some embodiments, the at least one modifying agents are ethylene dichloride and HSCH₂Ph.
The present invention also provides a composition comprising a polyelectrolyte layer that is functionalized with at least one modifying agent that is exposable to native chemical ligation with at least one wound active agent containing an amino terminal cysteine residue.
The present invention also provides a kit for treating a subject having a wound, comprising at least one cationic polyelectrolyte, at least one anionic polyelectrolyte, at least one modifying agent, at least one wound active agent containing an amino terminal cysteine residue, and instructions for using the kit to form a polyelectrolyte layer on the wound, followed by treatment with the at least one modifying agent and attachment of the at least one wound active agent by native chemical ligation. In some preferred embodiments, the at least one anionic polyelectrolyte is polyglutamic acid. In some preferred embodiments, the at least one modifying agents are ethylene dichloride and HSCH₂Ph.
In some embodiments, the present invention provides methods of treatment comprising: a) providing a subject having a wound, at least one wound modifying agent, and at least one wound active agent; b) contacting the wound with the at least one wound modification agent to provide a modified wound bed, and c) contacting the modified wound bed with the at least one wound active agent under conditions such that the at least one wound active agent is incorporated into the modified wound bed and healing of the wound is enhanced. In some embodiments, the modified wound bed is modified to present a functionalized surface reactive with the at least one wound active agent. In some embodiments, the wound active agent is applied to the modified wound bed to form a gradient. In some embodiments, the wound modifying agent alters a property of the wound bed selected from the group consisting of compliance, pH, alkalinity, and oxidative or reductive strength, net charge, hydrophilicity, osmotic strength, nanoscale or submicron topographic features, electroconductivity, MMP production, phagocytosis, and transglutaminase activity. In some embodiments, the wound modifying agent is applied to the wound bed by a method selected from the group consisting of coating, sprinkling, seeding, electrospinning, spattering, stamping, spraying, pumping, painting, smearing and printing. In some embodiments, the at least one wound modification agent is at least one crosslinker. In some embodiments, the at least one crosslinker is selected from the group consisting of a homobifunctional crosslinker, a heterobifunctional cross linker, a hetero- and homo-multifunctional crosslinker, and a photoactivatable crosslinker and combinations thereof. In some embodiments, the heterobifunctional crosslinker comprises an alkyne group. In some embodiments, the wound modifying agent comprises at least one polymer. In some embodiments, the at least one polymer is applied to the wound bed to form a polymer multilayer. In some embodiments, the at least one polymer is selected from the group consisting of a cationic polymer, an anionic polymer, a nonionic polymer an amphoteric polymer and combinations thereof. In some embodiments, the methods further comprise contacting the polymer multilayer with a crosslinker to form a functionalized surface reactive with the at least one wound active agent. In some embodiments, the at least one polymer is a polyelectrolyte multilayer preformed on a support so that the polyelectrolyte multilayer can be transferred from the support to the wound bed to form a modified wound bed. In some embodiments, the support is an elastomeric support. In some embodiments, the polymer multilayer is from 1 nm to 250 nm thick. In some embodiments, the polymer multilayer has a compliance of from 3 to 500 kPa. In some embodiments, the wound modifying agent is selected from the group consisting of nanoparticles and microparticles. In some embodiments, the nano- and microparticles are functionalized. In some embodiments, the functionalized bead is a mesoscopic cross-linker. In some embodiments, the at least one wound active agent is selected from the group consisting of trophic factors, extracellular matrices, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents, buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents.
In some embodiments, the present invention provides kits for treating a subject having a wound, comprising: a) at least one wound modification agent, b) at least one wound active agent; and c) instructions for using the kit to treat a wound bed with the at least one wound modification agent to provide a modified wound bed and for incorporating the wound active agent into the modified wound bed. In some embodiments, the at least one wound modification agent is selected from the group consisting of a covalent modifying agent, at least one polyelectrolyte, microparticle, nanoparticle, and combinations thereof. In some embodiments, the present invention provides methods of treatment comprising:
a) providing a subject having a wound, i) a cationic and anionic polyelectrolyte mixture, ii) a deprotection agent, iii) at least one covalent modification agent, iv) at least one molecule containing an azide group or alkyne group, and v) at least one wound active agent containing the other of an azide group or an alkyne group; b) contacting the wound with the polyelectrolyte mixture to form a polyelectrolyte layer on the wound; c) applying the deprotection agent to the polyelectrolyte layer to form a deprotected polyelectrolyte layer; d) applying the at least one covalent modification agent to the deprotected polyelectrolyte layer to form a modified deprotected polyelectrolyte layer; e) applying the at least one molecule containing an azide group or an alkyne group to the modified deprotected polyelectrolyte layer to covalently link the molecule containing an azide or an alkyne group to the modified deprotected polyelectrolyte layer; f) applying the at least one wound active agent containing the other of an azide group or an alkyne group to the modified deprotected polyelectrolyte layer covalently linked to the molecule containing an azide group, under conditions such that the at least one wound active agent is attached to the wound by click chemistry.
In some embodiments, the present invention provides a composition comprising a deprotected polyelectrolyte functionalized with at least one covalent modification agent linked to at least one molecule containing an azide group that is attached by click chemistry to at least one wound active agent containing an alkyne group.
In some embodiments, the present invention provides methods comprising a) providing a subject having a wound, a plurality of functionalized beads and at least one cytoactive factor, b) contacting the at least one cytoactive factor with the at least one functionalized biocompatible bead such that the at least one cytoactive factor is linked to the at least one functionalized biocompatible bead and c) applying the at least one functionalized biocompatible bead linked to the at least one cytoactive factor to a wound bed of the subject.
In some embodiments, the present invention provides methods of treatment comprising: a) providing a subject having a wound, at least one polymer, and at least one wound active agent b) applying the at least one polymer to the wound so that a polymer multilayer is formed on the wound; and c) incorporating the at least one wound active agent into the polymer multilayer during application of the at least one polymer, wherein the at least one wound active agent forms a gradient in the polymer multilayer.
In some embodiments, the present invention provides an article comprising a matrix formed from a biocompatible material, the matrix comprising at least one wound active agent, wherein the matrix is from 1 to 500 nm in thickness and has a compliance of from 3 to 500 kPa. In some embodiments, the matrix is functionalized. In some embodiments, the biocompatible material is selected from the group consisting of proteins and polymers. In some embodiments, the polymers are selected from the group consisting of polyanionic polymers, polycationic polymers, uncharged polymers, and amphoteric polymers and combinations thereof, and wherein the polymers from a multilayer. In some embodiments, the proteins are extracellular matrix proteins selected from the group consisting of laminin, vitronectin, fibronection, keratin, collagen, and combinations thereof. In some embodiments, the matrix is supported by a solid support selected from the group consisting of silicone, siloxane elastomers, latex, nylon, nylon mesh, biological tissue, silk, polyurethane, Teflon, polyvinyl alcohol membranes, and polyethylene oxide membranes. In some embodiments, the at least one wound active agent is distributed on the matrix so that a gradient is formed. In some embodiments, the matrix is at least partially PEGylated. In some embodiments, the present invention provides methods comprising, applying the articles described above to a wound on a subject, wherein the article enhances healing of the wound. In some embodiments, the present invention provides kits comprising the articles described above in a sterile package.
In some embodiments of the present invention, the compositions and methods described above enhance wound healing. The present invention contemplates that wound healing may be enhanced in a variety of ways. In some embodiments, the compositions and methods minimize contracture of the wound as to best favor function and cosmesis. In some embodiments, compositions and methods promote wound contracture to best favor function and cosmesis. In some embodiments, the compositions and methods promote vascularization. In some embodiments, the compositions and methods inhibit vascularization. In some embodiments, the compositions and methods promote fibrosis. In some embodiments, the compositions and methods inhibit fibrosis. In some embodiments, the compositions and methods promote epithelial coverage. In some embodiments, the compositions and methods inhibit epithelial coverage. In some embodiments, the compositions and methods of the present invention modulates one or properties of cells in the wound environment or in the immediate vicinity of the wound. The properties that are modulated, e.g., are increased or decreased, include, but are not limited to adhesion, migration, proliferation, differentiation, extracellular matrix secretion, phagocytosis, MMP activity, contraction, and combinations thereof.
In some embodiments, the present invention provides for the use of any of the compositions described above or elsewhere herein to enhance healing of a wound or modulate one or more properties of cells in the wound environment or in the immediate vicinity of the wound. In some embodiments, the present invention provides for the use of a combination of a wound modifying agent and wound active agent to enhance healing of a wound to enhance healing of a wound or modulate one or more properties of cells in the wound environment or in the immediate vicinity of the wound. In some embodiments, the present invention provides for the use of the articles described above to enhance healing of a wound or modulate one or more properties of cells in the wound environment or in the immediate vicinity of the wound.
In some embodiments, the present invention provides an article or composition comprising a polymer multilayer comprising at least one polymer, the polymer multilayer having associated therewith particles selected from the group consisting of nanoscale and microscale particles. In some embodiments, the at least one polymer is selected from the group consisting of a cationic polymer, an anionic polymer, a nonionic polymer an amphoteric polymer and combinations thereof. In some embodiments, the polymer multilayer is from 1 nm to 500 nm thick, preferably from 1 nm to 250 nm thick. In some embodiments, the polymer multilayer has a compliance of from 3 kPa to 500 kPa, 3 kPa to 10 MPa, or 3 kPa to 5 GPa. In some embodiments, the particles are polymeric particles. In some embodiments, the particles are selected from the group consisting of spherical, ovoid, and cylindrical shaped particles. In some embodiments, the diameter of the particles is greater than the thickness of the polymer multilayer.
In some embodiments, the articles or compositions comprise at least one wound active agent in association with the composition. In some embodiments, the wound active agent is selected from the group consisting of antimicrobials, trophic factors, extracellular matrices, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents, buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents. In some embodiments, the wound active agent is dispersed in the polymer multilayer. In some embodiments, the wound active agent is covalently associated with the polymer multilayer. In some embodiments, the particles are functionalized. In some embodiments, the wound active agent is attached to the particles. In some embodiments, the wound active agent is contained within the particle.
In some embodiments, the polymer layer is disposed on a support. In some embodiments, the support is a polymeric support. In some embodiments, the polymeric support is a polymer composition that is distinct from the polymer multilayer. In some embodiments, the polymeric support is an elastomeric polymer. In some embodiments, the polymeric support and the polymer multilayer are separated by a water soluble material. In some embodiments, the polymeric support is water soluble. In some embodiments, the water soluble support comprises polyvinyl alcohol. In some embodiments, the support is a wound dressing. In some embodiments, the support is a biologic wound dressing. In some embodiments, the polymer multilayer is deposited onto the support by a method selected from the group consisting of adsorption from solution and spin coating.
In some embodiments, the particles have an elastic modulus of from about 0.5 to about 10 GPa. In some embodiments, the particles are interspersed or dispersed in the polymer multilayer. In some embodiments, the particles are displayed on a surface of the polymer multilayer. In some embodiments, the particles are underneath the polymer multilayer. In some embodiments, the particles are between the polymer multilayer and the support. In some embodiments, the particles are on the surface of the polymer multilayer and have a diameter that is greater than the thickness of the polymer multilayer, and wherein the article further comprises an antimicrobial silver composition.
In some embodiments, the present invention provides methods of modifying a surface comprising contacting a surface with a polymer multilayer comprising at least one polymer, the polymer multilayer having associated therewith particles selected from the group consisting of nanoscale and microscale particles under conditions such that the polymer multilayer is transferred to the surface. In some embodiments, pressure is applied to the polymer multilayer to effect transfer to the surface. In some embodiments, the pressure is from about 10 to about 500 kPa. In some embodiments, the polymer multilayer is disposed on a support. In some embodiments, the support is from about 1 micrometer to about 10 mm in thickness. In some embodiments, the surface is a wound dressing. In some embodiments, the wound dressing is a biologic wound dressing. In some embodiments, the polymer multilayer is deposited on the support by a process selected from the group consisting of adsorption from solution, spraying, and spin coating. In some embodiments, the support is an elastomeric support. In some embodiments, the surface is a soft or compliant surface. In some embodiments, the soft surface has an elastic modulus of from about 10 to about 100 kPa. In some embodiments, the soft surface is a biological surface. In some embodiments, the biological surface is selected from the group consisting of skin, a wound bed, hair, a tissue surface, and an organ surface. In some embodiments, the biological surface comprises molecules selected from the group consisting of a proteins, a lipids, a carbohydrates, and combinations thereof. In some embodiments, the surface comprises (e.g., is coated with or displays) with glycosaminoglycans, collagen and/or hyaluronic acid. In some embodiments, the surface is a surface on a biomedical device. In some embodiments, the surface is a silicone surface. In some embodiments, the at least one polymer is selected from the group consisting of a cationic polymer, an anionic polymer, a nonionic polymer an amphoteric polymer and combinations thereof. In some embodiments, the polymer multilayer is from 1 nm to 500 nm thick. In some embodiments, the polymer multilayer has a compliance of from 3 kPa to 500 kPa, 3 kPa to 10 MPa, or 3 kPa to 5 GPa. In some embodiments, the particles are polymeric particles. In some embodiments, the diameter of the particles is greater than the thickness of the polymer multilayer. In some embodiments, the particles are selected from the group consisting of spherical, ovoid, and cylindrical shaped particles. In some embodiments, the polymer multilayer comprises at least one wound active agent. In some embodiments, the wound active agent is selected from the group consisting of trophic factors, extracellular matrices, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents, buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, antimicrobial agents, growth factors, oligopeptides, saccharides, polysaccharides, synthetic molecules comprising a biological moiety, metal particles, electrodes, magnetic particles, honey, and anti-cancer agents. In some embodiments, the wound active agent is dispersed in the polymer multilayer. In some embodiments, the wound active agent is covalently associated with the polymer multilayer. In some embodiments, the particles are functionalized. In some embodiments, the wound active agent is attached to the particles. In some embodiments, the particles have an elastic modulus of from about 0.5 to about 10 GPa. In some embodiments, the particles are dispersed in the polymer multilayer. In some embodiments, the particles are displayed on a surface of the polymer multilayer.
In some embodiments, the transfer is done in the substantial absence of a solution or a liquid solvent. In some embodiments, the transfer is a substantially or completely dry transfer. In some embodiments, the transfer is performed through a gas phase. In some embodiments, the transfer is performed in an environment where the humidity is less than 100% of saturation. In some embodiments, the transfer is performed in the absence of liquid water.
In some embodiments, the present invention provides an article or composition comprising a polymer multilayer loaded with an antimicrobial silver composition in the amount of about 100 to about 500 μg/cm²of the polymer multilayer and/or having a releasable antimicrobial silver composition incorporated therein, wherein the releasable antimicrobial silver composition is releasable in an amount of about 0.01 and 100 μg/cm²of the polymer multilayer per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 100 μg/cm²of the polymer multilayer per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 20 μg/cm²of the polymer multilayer per day. In some embodiments, the antimicrobial silver composition is releasable in an amount of about 0.05 and 5 μg/cm²of the polymer multilayer per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 2 μg/cm²of the polymer multilayer per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 1 μg/cm²of the polymer multilayer per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.1 to 0.5 μg/cm²of the polymer multilayer per day. In some embodiments, the antimicrobial silver composition comprises silver nanoparticles. In some embodiments, the silver nanoparticles are zerovalent silver nanoparticles. In some embodiments, the composition provides at least 99.99% killing of Staphylococcus epidermis. In some embodiments, the article does not substantially impair the healing of wounds. In some embodiments, the antimicrobial silver composition permits at least 90% viability of NIH-3T3 cells. In some embodiments, the viability is assessed after 24 h of incubation of the NIH-3T3 cells on the composition in the presence of growth media. In some embodiments, the article is a film. In some embodiments, the article is a three-dimensional object, at least a portion of which is coated with the polymer multilayer. In some embodiments, the three-dimensional object is a medical device.
In some embodiments, the article is selected from the group consisting of a polymeric support, an elastomeric support, a wound care device, a wound dressing and a biologic wound dressing. In some embodiments, the medical device partially contacts a subject. In some embodiments, the medical device is completely implanted in a subject. In some embodiments, the at least one of the polymers comprises poly(allylamine hydrochloride). In some embodiments, at least one of the polymers comprises poly(acrylic acid). In some embodiments, the articles or compositions further comprise at least one additional antimicrobial agent.
In some embodiments, the present invention provides a method for treating a wound comprising providing a subject with a wound and contacting the wound with an article or composition as described above.
In some embodiments, the present invention provides kits for the treatment of a wound in a subject, comprising an article or composition as described above and instructions for applying the article to the wound. In some embodiments, the kits further comprise additional wound dressing material. In some embodiments, the wound dressing material is a biologic wound dressing.
In some embodiments, the present invention provides an article or composition comprising a solid support comprising a releasable antimicrobial silver composition, wherein the releasable antimicrobial silver composition is loaded at an amount of from 1 to about 500 μg/cm²of the solid support and/or releasable in an amount of about 0.01 and 100 μg/cm²of the solid support per day. In some embodiments, the solid support is selected from the group consisting of a polymeric support, an elastomeric support, nanoparticles, microparticles, a wound dressing and a biologic wound dressing. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 100 μg/cm²of the solid support per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 20 μg/cm²of the solid support per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 5 μg/cm²of the solid support per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 2 μg/cm²of the solid support per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 1 μg/cm²of the solid support per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.1 to 0.5 μg/cm²of the solid support per day. In some embodiments, the antimicrobial silver composition comprises silver nanoparticles. In some embodiments, the silver nanoparticles are zerovalent silver nanoparticles. In some embodiments, the article does not substantially impair the healing of wounds. In some embodiments, the articles or compositions further comprise at least one additional antimicrobial agent.
In some embodiments, the present invention provides methods for treating a wound comprising providing a subject with a wound and contacting the wound with the article or composition as described above.
In some embodiments, the present invention provides methods for synthesizing a composition for treatment of a wound, comprising: a) assembling alternating layers of polymers to form a film or coating and b) during the assembling, incorporating an antimicrobial silver composition into the alternating layers of polymers.
In some embodiments, the present invention provides methods for synthesizing a composition for treatment of a wound, comprising: a) assembling alternating layers of polymers to form a film or coating; b) incubating the film or coating in bulk solution of a silver salt; c) exposing the film or coating to a reducing agent; and d) selecting films or coatings for use having a silver loading level between 0.01 and 100 μg/cm². In some embodiments, at least one of the polymers comprises a solution containing poly(allylamine hydrochloride). In some embodiments, at least one of the polymers comprises a solution containing poly(acrylic acid). In some embodiments, the bulk solution of a silver salt comprises silver nitrate. In some embodiments, the concentration of Ag⁺ in the silver nitrate solution is from 0.005 mM to 5 mM. In some embodiments, the pH of the poly(acrylic acid) solution is from 2.5 to 7.5.
In some embodiments, the present invention provides a solid support; and a polymer multilayer supported by the solid support, the polymer multilayer comprising at least one wound active agent. In some embodiments, the article further comprises a water soluble material between the solid support and the polymer multilayer. In some embodiments, the solid support comprises a polymer. In some embodiments, the polymer is an elastomeric polymer. In some embodiments, the elastomeric polymer is a silicon polymer. In some embodiments, the silicon polymer is selected from the group consisting of polydimethylsiloxane and medical grade silicone. In some embodiments, the polymer multilayer has a thickness of from about 1 nm to 500 nm. In some embodiments, the polymer multilayer has a compliance of from about 3 kPa to 5 GPa, preferably about 3 kPa to 500 kPa. In some embodiments, the polymer multilayer comprises nanoscale to microscale particles incorporated therein. In some embodiments, the particles have a diameter that is greater than thickness of the polymer multilayer. In some embodiments, the at least one wound active agent is an antimicrobial silver composition. In some embodiments, the silver loading of the polyelectrolyte multilayer is between about 0.01 and 500 μg/cm²of the antimicrobial silver composition. In some embodiments, the antimicrobial silver composition comprises silver nanoparticles. In some embodiments, the silver nanoparticles are zerovalent silver nanoparticles. In some embodiments, the antimicrobial silver composition comprises multivalent silver ions carried by zirconium phosphate. In some embodiments, the solid support comprises a material selected from the group consisting of a foam, a transparent thin film, a hydrogel, hydrofibers, hydrocolloids, alginate fibers, and combinations thereof. In some embodiments, the solid support comprises a material selected from the group consisting of super absorbent polymers (SAP), silica gel, sodium polyacrylate, potassium polyacrylamides and combinations thereof. In some embodiments, the solid support comprises an absorbent material. In some embodiments, the polymer multilayer is transferred to the support in the substantial absence of a solvent. In some embodiments, the absorbent material is selected from the group consisting of a fabric, e.g., cotton or nylon gauze, and polymer foam. In some embodiments, the absorbent material comprises a first surface comprising an anti-adherent material. In some embodiments, the polymer multilayer is deposited on the first surface comprising an anti-adherent material. In some embodiments, the absorbent material comprises a second surface fixed to an adhesive material. In some embodiments, the adhesive material is sized to extend from one or more edges of the absorbent material so that the absorbent material can be exposed to the skin of a subject. In some embodiments, the article further comprises a removable sheet, wherein the article is removably affixed to the removable sheet. In some embodiments, the article is packaged in a sterile package. In some embodiments, the polymer multilayer has a thickness of from about 1 nm to 500 nm. In some embodiments, the polymer multilayer has a compliance of from about 3 to 500 kPa. In some embodiments, the polymer multilayer comprises nanoscale to microscale particles incorporated therein. In some embodiments, the at least one wound active agent is an antimicrobial silver composition. In some embodiments, the silver loading of the polyelectrolyte multilayer is between about 0.01 and 500 μg/cm²of the antimicrobial silver composition. In some embodiments, the antimicrobial silver composition comprises silver nanoparticles. In some embodiments, the silver nanoparticles are selected from the group consisting of zerovalent silver nanoparticles and multivalent silver ions (carried by zirconium phosphate).
In some embodiments, the solid support comprises a biologic wound dressing. In some embodiments, the biologic wound dressing comprises (e.g., is coated with or displays) a biological molecule selected from the group consisting of collagen, hyaluronic acid, glycosaminoglycans, keratin, fibronectin, vitronectin, laminin, and combinations or fragments thereof. In some embodiments, the biopolymer is supported on a silicone film. In some embodiments, the silicone film comprises a fabric support. In some embodiments, the fabric support is a nylon fabric support. In some embodiments, the polymer multilayer is deposited on the silicone film. In some embodiments, the polymer multilayer has a thickness of from about 1 nm to 500 nm. In some embodiments, the polymer multilayer has a compliance of from about 3 to 500 kPa. In some embodiments, the polymer multilayer comprises nanoscale to microscale particles incorporated therein. In some embodiments, the particles have a diameter that is greater than the thickness of the polymer multilayer. In some embodiments, the at least one wound active agent is an antimicrobial silver composition. In some embodiments, the silver loading of the polyelectrolyte multilayer is between about 0.01 and 500 μg/cm²of the antimicrobial silver composition. In some embodiments, the antimicrobial silver composition comprises silver nanoparticles. In some embodiments, the silver nanoparticles are selected from the group consisting of zerovalent and multivalent silver nanoparticles.

DESCRIPTION OF THE FIGURES

FIG. 1 provides a schematic of a wound bed modified with a polyelectrolyte multilayer.

FIG. 2 provides a schematic of a wound bed modified with covalent modifying agents.

FIG. 3 exemplifies the covalent immobilization of proteins to model amine-terminated treated glass surfaces.

FIG. 4 shows ex vivo results for multilayer deposition of polyelectrolytes polystyrene sulfonate (PSS) and FITC-labelled poly (allylamine hydrochloride) (FITC-PAH).

FIG. 5 demonstrates the difference in healing of full thickness cutaneous wounds in diabetic (db/db) mice compared to control (wild type) mice.

FIG. 6 is exemplary of the use of beads for healing a wound bed. In this example, carboxylic acid-terminated beads are activated outside the wound bed by using NHS and EDC. The activated beads are introduced into the wound bed and are immobilized in the wound bed via reaction of the activated surfaces of the beads with amine groups present in the wound bed. Growth factors are introduced into the wound bed and immobilized via reaction with the exposed surfaces of the activated beads.

FIG. 7A-P provides a list of antimicrobial polypeptides, identified by name and AMSDb database ID number.

FIG. 8 shows the viability of NIH-3T3 mouse fibroblasts after 24 hr incubation in growth media on silver-loaded polyelectrolyte multilayers (PEMs) (Example 13).

FIG. 9 shows viable bacteria detected on silver-loaded PEMs 8 hr after incubation with 10⁸cfu/ml of S. epidermidis in buffer. PEMs with varying silver loading were prepared by incubating them with serial decimal dilutions of bulk Ag⁺ solution. PEMs incubated with 5 mM Ag⁺ (silver nitrate) solution as indicated in this figure contained ˜0.38 μg/cm²(where no cytotoxicity towards NIH-3T3 cells was observed in FIG. 8), while silver loading in rest of the PEMs was below the detection limit of the elemental analysis spectrometer.

FIG. 10 shows NIH 3T3 cells after 24 h incubation on glass surfaces coated with PEMs (10.5 bilayers of PAH_7.5/PAA_x) without silver (a,c,e) or with silver nanoparticles at concentrations (b) 0.62, (d) 0.48, or (f) 0.39 μg/cm². PEMs were prepared with PAA solution of pH 5.5 (a, b), or 6.5 (c, d) or 7.5 (e, f).

FIG. 11 provides a schematic depiction of one embodiment of polymer multilayers with microscale beads.

FIG. 12 provides a graph depicting transfer of a polymer multilayer containing microscale beads to a soft surface as compared to transfer of a polymer multilayer without microscale beads.

DEFINITIONS

To facilitate an understanding of the invention set forth in the disclosure that follows, a number of terms are defined below.
The term “wound” refers broadly to injuries to the skin and subcutaneous tissue initiated in different ways (e.g., pressure sores from extended bed rest and wounds induced by trauma) and with varying characteristics. The methods and compositions described herein are useful for treatment of all types of wounds, including wounds to internal and external tissues. Wounds may be classified into one of four grades depending on the depth of the wound: i) Grade I: wounds limited to the epithelium; ii) Grade II: wounds extending into the dermis; iii) Grade III: wounds extending into the subcutaneous tissue; and iv) Grade IV (or full-thickness wounds): wounds wherein bones are exposed (e.g., a bony pressure point such as the greater trochanter or the sacrum).
The term “partial thickness wound” refers to wounds that encompass Grades I-III; examples of partial thickness wounds include burn wounds, pressure sores, venous stasis ulcers, and diabetic ulcers. The term “deep wound” is meant to include both Grade III and Grade IV wounds. The present invention contemplates treating all wound types, including deep wounds and chronic wounds.
The term “chronic wound” refers to a wound that has not healed within 30 days.
The phrases “promote wound healing,” “enhance wound healing,” and the like refer to either the induction of the formation of granulation tissue of wound contraction and/or the induction of epithelialization (i.e., the generation of new cells in the epithelium). Wound healing is conveniently measured by decreasing wound area.
The term “wound active agent” refers to known or potential chemical compounds that induce a desired pharmacological, physiological effect useful in the treatment and healing of a wound, wherein the effect may be prophylactic or therapeutic. The terms also encompass pharmaceutically acceptable, pharmacologically active derivatives of those active agents specifically mentioned herein, including, but not limited to, trophic factors, extracellular matrices, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents (including but not limited to ionic silver, elemental silver, and silver nanoparticles), buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents.
The term “polymer multilayer” refers to the composition formed by sequential and repeated application of polymer(s) to form a multilayered structure. For example, polyelectrolyte multilayers are polymer multilayers are formed by the alternating addition of anionic and cationic polyelectrolytes to a wound or support. The term “polymer multilayer” also refers to the composition formed by sequential and repeated application of polymer(s) to a wound or to a solid support. In addition, the term “polymer layer” can refer to a single layer composed of polymer molecules, such as anionic or cationic polyelectrolyte molecules, existing either as one layer within multiple layers, or as a single layer of only one type of polyelectrolyte molecules on a wound or support. While the delivery of the polymers to the wound bed or support is sequential in preferred embodiments, the use of the term “polymer multilayer” is not limiting in terms of the resulting structure of the coating. It is well understood by those skilled in the art that inter-diffusion of polymers such as polyelectrolytes can take place leading to structures that may be well-mixed in terms of the distribution of anionic and cationic polyelectrolytes. It is also understood that the term polyelectrolyte includes polymer species as well as nanoparticulate species, and that it is not limiting in scope other than to indicate that the species possesses multiple charged or partially charged groups. It is also well understood by those skilled in the art that multilayer structures can be formed through a variety of interactions, including electrostatic interactions and others such as hydrogen bonding. Thus, the use of the term “polyelectrolyte” is not limiting in terms of the interactions leading to the formation of the wound bed constructs.
The term “crosslinked” herein refers to a composition containing intermolecular crosslinks and optionally intramolecular crosslinks as well, arising from the formation of covalent bonds. Covalent bonding between two crosslinkable components may be direct, in which case an atom in one component is directly bound to an atom in the other component, or it may be indirect, through a linking group. A crosslinked structure may, in addition to covalent bonds, also include intermolecular and/or intramolecular noncovalent bonds such as hydrogen bonds and electrostatic (ionic) bonds.
The term “covalent modification agent” refers to any molecule that covalently links molecules to each other. Covalent modification agents include homobifunctional and heterobifunctional cross-linkers as well as photoactivatable cross linkers.
The term “homobifunctional cross-linker” refers to a molecule used to covalently link identical or similar molecules to each other. Homobifunctional cross-linkers have two identical reactive groups; thus, a homobifunctional cross-linker can only link molecules of the same type to each other. Conversely, a “heterobifunctional cross-linker” refers to a molecule used to covalently link dissimilar molecules to each other, because it has two or more different reactive groups that can interact with various molecules of different types. Hetero- and homo-multifunctional crosslinkers refers to multivalent crosslinkers with both hetero- and homo-crosslinking functionalities. Activated dendrimers are an example of multifunctional crosslinkers.
The term “subject” refers to any animal (e.g., a mammal), including, but not limited to, humans, non-human primates, rodents, dogs, cats, and the like, which is to be the recipient of a particular treatment. Typically, the terms “subject” and “patient” are used interchangeably herein.
The term “surfactant” refers to an amphiphilic material that modifies the surface and interface properties of liquids or solids. Surfactants can reduce the surface tension between two liquids. Detergents, wetting agents, emulsifying agents, dispersion agents, and foam inhibitors are all surfactants.
The term “block copolymer” refers to a polymer consisting of at least two monomers. In a block copolymer, adjacent blocks are constitutionally different, i.e. adjacent blocks comprise constitutional units derived from different species of monomer or from the same species of monomer but with a different composition or sequence distribution of constitutional units. A block copolymer can be thought of as two homopolymers joined together at the ends.
The term “solvent” refers to a liquid that can dissolve a substance. The term “organic solvent” refers to a solvent derived from a petroleum-based product.
The term “polyelectrolyte” refers to a water-soluble macromolecular polymer substance containing many repeating ionic constituent units, including cations and anions.
The term “primary amine” refers to a derivative of ammonia in which a hydrogen has been replaced by a hydrocarbon unit. Primary amines have the general formula RNH₂and examples include, but are not limited to, aniline, methylamine, and 1-propylamine.
The term “DNA delivery agent” refers to any molecule that can bring DNA into contact with an identified target. In some instances, a DNA delivery agent causes uptake of DNA into a cell or cells, in vitro or in vivo. DNA delivery agents can be viruses including, but not limited to, adenoviruses and retroviruses. DNA delivery agents can also be non-viral agents including, but not limited to, plasmids, lipids, liposomes, polymers and peptides.
The term “exposable” refers to anything that is capable of being exposed. An exposable surface or molecule is one that is made available to interaction with other surfaces or molecules. For example, in the context of the present invention, a covalent modification agent is exposable to a wound active agent; thus, the two agents can interact with each other and form covalent bonds.
The term “functionalized” refers to a modification of an existing molecular segment to generate or introduce a new reactive functional group (e.g., a maleimido or succinimidyl group) that is capable of undergoing reaction with another functional group (e.g., a sulfhydryl group) to form a covalent bond. For example, a component containing carboxylic acid (—COOH) groups can be functionalized by reaction with N-hydroxy-succinimide or N-hydroxysulfosuccinimide using known procedures, to form a new reactive functional group in the form of an activated carboxylate (which is a reactive electrophilic group), i.e., an N-hydroxysuccinimide ester or an N-hydroxysulfosuccinimide ester, respectively. In another example, carboxylic acid groups can be functionalized by reaction with an acyl halide, e.g., an acyl chloride, again using known procedures, to provide a new reactive functional group in the form of an anhydride.
As used herein, the term “aqueous solution” includes solutions, suspensions, dispersions, colloids, and the like containing water.
As used herein, the term “click chemistry” refers to the use of chemical building blocks with built-in high-energy content to drive a spontaneous and irreversible linkage reaction with appropriate complementary sites in other blocks. These chemical reactions (e.g., including, but not limited to, those between azide and acetylene groups that combine readily with each other) are specific and result in covalent linkage between the two molecules.
The term “native chemical ligation” refers to a chemoselective reaction of two unprotected peptide segments. The reaction results in an initial thioester-linked species, then spontaneous rearrangement of this transient intermediate occurs, yielding a full-length product with a native peptide bond at the ligation site.
The term “specific protein binding” refers to an interaction between two or more proteins that have high affinity and specificity for each other. Proteins must bind to specific other proteins in vivo in order to function. The proteins are required to bind to only one or a few other proteins of the few thousand proteins typically present in vivo; these interactions are employed in vitro in the present invention to attach wound active agents to the wound. In the context of the present invention, specific protein binding interactions include, but are not limited to, those between biotin and avidin, neutravidin, or streptavidin; glutathione-S-transferase and glutathione; and nickel-nitrilotriacetic acid and polyhistidine.
The term “device” refers to an object that contacts the body or bodily fluid of a subject for therapeutic or prophylactic purposes. Some devices may partially or indirectly contact the body or bodily fluid of a subject (e.g., catheter, dialysis tubing, diagnostic sensors, drug delivery devices), while other devices are completely imbedded in or encompassed by the body of a subject (e.g., stent, pacemaker, internally implanted defibrillator, angioplasty balloon, orthopedic device, spinal cage, implantable drug pump, artificial disc, ear disc).
The term “selective toxicity” refers to the property of differentially toxic effects on mammalian versus microbial cells. For example, a selectively toxic agent may effectively kill bacterial cells while permitting growth and viability of mammalian cells.
The term “toxic” refers to any detrimental or harmful effects on a subject, a cell, or a tissue as compared to the same cell or tissue prior to the administration of the toxicant.
As used herein, the terms “nanoparticle” and “nanoscale particles” are used interchangeably and refer to a nanoscale particle with a size that is measured in nanometers, for example, a nanoscopic particle that has at least one dimension of less than about 1000, 500, or 100 nm. Examples of nanoparticles include nanobeads, nanofibers, nanohorns, nano-onions, nanorods, and nanoropes.
As used herein, the term “microparticle” and “microscale particles” are used interchangeably and refers to a microscale particle with a size that is measured in micrometers, for example, a microscale particle that has at least one dimension of less than about 10 micrometers, 5 micrometers, or 2 micrometers.
The term “wound dressing” refers to materials placed proximal to a wound that have absorbent, adhesive, protective, osmoregulatory, pH-regulatory, or pressure-inducing properties. Wound dressings may be in direct or indirect contact with a wound. Wound dressings are not limited by size or shape. Indeed, many wound dressing materials may be cut or configured to conform to the dimensions of a wound. Examples of wound dressing materials include but are not limited to gauze, adhesive tape, bandages, and commercially available wound dressings including but not limited to adhesive bandages and pads from the Band-Aid® line of wound dressings, adhesive bandages and pads from the Nexcare® line of wound dressings, adhesive bandages and non-adhesive pads from the Kendall Curity Tefla® line of wound dressings, adhesive bandages and pads from the Tegaderm® line of wound dressings, adhesive bandages and pads from the Steri-Strip® line of wound dressings, the COMFEEL® line of wound dressings, adhesive bandages and pads, the Duoderm® line of wound dressings, adhesive bandages and pads, the TEGADERM™ line of wound dressings, adhesive bandages and pads, the OPSITE® line of wound dressings, adhesive bandages and pads, and biologic wound dressings. A “biologic wound dressing” is a type of wound dressing that comprises, e.g., is coated with or incorporates, cells and/or one or more biomolecules or fragments of biomolecules that can be placed in contact with the wound surface. The biomolecules may be provided in the form of an artificial tissue matrix. Examples of such biomolecules include, but are not limited, to collagen, hyaluronic acid, glycosaminoglycans, laminin, vitronectin, fibronectin, keratin, antimicrobial polypeptides and combinations thereof. Examples of suitable biologic wound dressings include, but are not limited to, BIOBRANE™, Integra™, Apligraf®, Dermagraft®, Oasis®, Transcyte®, Cryoskin® and Myskin®.
As used herein, the term “antimicrobial silver composition” refers to a composition that comprises silver as an active antimicrobial agent. Examples of “antimicrobial silver compositions” include, but are not limited to silver nanoparticles, elemental silver, zero valent silver, multivalent silver ions carried by zirconium phosphate (ZP—Ag)(See, e.g., Wound Repair and Regeneration, 16: 800-804), and silver containing compounds such as silver sulfadiazine and related compounds. The term “releasable antimicrobial silver composition” refers to a antimicrobial silver composition that can be released from a material, for example, a polymer multilayer solid support, so that antimicrobial activity can be observed. The release of the antimicrobial silver composition can be defined as an amount of the composition released from a defined area or volume of the material.

DETAILED DESCRIPTION OF THE INVENTION

The complex nature of wounds, and the lack of significant clinical progress based on current therapies, indicates the urgent need for new and unconventional approaches. The microenvironment of the pathologic/chronic wound bed is dysregulated with alterations in extracellular matrix constituents, degradative enzymes, growth factor and other cytoactive factor activity. The present invention provides compositions and methods for engineering of the wound bed itself by, for example, altering the surface chemistry/structure of the wound bed to promote favorable cell behaviors that accelerate wound healing. In some embodiments, the wound bed is first treated with a priming agent (i.e., primer) that provides a uniform, reactive bed on the wound surface. The primed wound bed is then treated with a desired agent, such a wound active agent.
In normal wound healing, the coordinated interplay between fibroblasts, vascular cells, extracellular matrix components and epithelial cells results in a seamless progression through an inflammatory reaction, wound repair, contracture and coverage by an epithelial barrier. However, in many subjects with dysregulated wound microenvironment, systemic disease or other confounding circumstances, the wound healing processes become asynchronous resulting in an indolent ulcer (Pierce, 2001, Am. J. Pathol. 159:399). In other subjects, a loss or lack of regulatory responses to appropriately modulate cellular behaviors during healing causes an exuberant proliferative response that in itself is a problem for the subject. This is particularly true for patients prone to keloid formation or in burn patients where excessive fibroblastic proliferation and collagen production result in disfiguring and disabling scar formation.
It is clear that across the spectrum of non-healing wounds that there are a variety of inciting mechanisms and wound microenvironments. These wounds exhibit pathology at many junctures in the progression to closure. Deficits in angiogenesis, fibroblastic responses and re-epithelialization all play a role in chronic wounds. Thus, a single factor treatment approach to chronic wounds is not likely to be fruitful across the disparate array of wounds presented in the clinical milieu. In such a heterogeneous environment, a more promising strategy involves the identification of compounds that are able to modulate specific aspects of the cellular response and behavior in the wound environment, providing the potential for custom crafting of a healing response tailored to the individual wound and patient.
Due to the heterogeneous spectrum of wound environments, it is contemplated that stimulating a “desirable” healing response is best achieved by a differential modulation of the cellular responses within the wound. The present invention provides for the selection of a subset of cytoactive compounds from a list of candidates for immobilization into the wound bed so as to differentially modulate the endothelial, fibroblastic and epithelial components within the healing response. As such, the present invention provides the potential to achieve high quality healing responses in a variety of clinical conditions, thereby providing a strategy for engineering the wound bed for personalized therapeutics for each unique wound healing challenge encountered by a clinician. Specific examples where differential modulation of the cellular responses within the wound would yield substantial benefit include chronic wounds in diabetics or venous stasis ulcers, where pancellular promotion of healing responses is desired but in particular a vibrant angiogenic response is needed to support all of the other aspects of wound healing. In other wounds, where the strength of the healed wound is a key concern, modulation to promote a fibroblastic response with a normal angiogenic and epithelial component is desirable.
In contrast, in some burns, such as deep second degree burns where dermal and hair shaft epithelial elements persist to replace lost tissues, a rich angiogenic and epithelial response is needed, but it is desirable to mitigate the fibroblastic reaction to reduce scar hypertrophy, contracture and disfigurement. A similar mitigation is desirable in healing subjects prone to keloid formation where the proliferative fibroblastic response in these wounds must be suppressed. It is also advantageous in wounds near joints or orifices to be able to promote rapid healing and coverage with epithelium but modulate the fibroblastic response so that improved suppleness of the tissue is retained. Modulation of the fibroblastic response in this way has the potential to provide superior clinical outcomes and reduce the need for subsequent reconstructive procedures targeted at recovery of limb or other critical bodily functions. The feasibility of such an approach has been demonstrated previously, such as in the report by Muehlberger and colleagues on the effects tretinoin on incisional wounds (Muehlberger et al., 2005, J. Am. Acad. Derm. 52:583). In that study, application of tretinoin resulted in an increased fibroblastic proliferation but the production of collagen was diminished.
The modification of surfaces has become an important challenge in the last decade for applications in implant materials, prostheses, and artificial organs, allowing broad medical applications for implant and tissue engineering (Langer and Vacanti, 1993, Science 260:920); Peppas and Langer, 1994, Science 263:1715; Angelova and Hunkeler, 1999, Trends Biotechnol. 17:409). For the improved integration efficiency of implants, several approaches, involving the alteration of physicochemical, morphological, and biochemical properties of device surfaces, have been investigated in an effort to obtain a suitable bone-implant interface. Self-assembled monolayers (SAMs) or Langmuir-Blodgett techniques have been commonly employed to produce new interfaces (Mrksich, 1997, Curr. Opin. Colloid Interface Sci. 2:83; Lösche, 1997, Curr. Opin. Solid State Mater. Sci. 2:546).
More recently, a new versatile method of self assembled architectures based on the alternate deposition of polyanions and polycations has been developed for the buildup of multilayered polyelectrolyte films (Decher, 1997, Science 277:1232). Besides varying film thickness, roughness, and porosity, it is also possible to incorporate in the film architecture functionalized macromolecules (Caruso et al., 1997, Langmuir 13:3427; Cassier et al., 1998, Supramol. Sci. 5:309). It has also been demonstrated that the layer-by-layer deposition process is not limited in applicability to polyelectrolytes, but can be applied to viruses, nanoparticles, non-ionic polymers, proteins and other forms of microscopic and nanoscopic matter. A recent review provides information on a wide range of species and interfacial structures that can be formed by the layer-by-layer deposition procedure. The scope of the invention described herein is not limited to polyelectrolytes but applies to all species that have been demonstrated to be incorporated into interfacial structures by the layer-by-layer deposition process.
The present invention provides a variety of embodiments for altering the composition of the wound bed. In some embodiments, a wound modifying agent is applied to prime the wound bed. As described in detail below, wound modifying agents are agents that applied to a wound bed and either covalently or noncovalently modify the wound bed. Examples of wound modifying agents include homobifunctional and heterobifunctional linkers, polyelectrolytes, non-ionic polymers, combinations of polyelectroloytes and non-ionic polymers, and nano- and micro-particles including beads and needles. In some embodiments, the wound modifying agent alters a property of the wound bed selected from the group consisting of compliance, pH, alkalinity, and oxidative or reductive strength, net charge, hydrophilicity, osmotic strength, nanoscale or submicron topographic features, electroconductivity, MMP production, phagocytosis, and transglutaminase activity. In preferred embodiments, the wound modifying agents are used to incorporate wound active agents so that the wound active agents are localized to the wound bed. The wound active agents can be covalently or noncovalently attached to the wound modifying agent. Furthermore, the wound active agents may form a gradient via the wound modifying agent. In further embodiments, the wound modifying agents alter the compliance of the wound bed. In these embodiments, the polymers or nano- or micro-particles have a predetermined hardness. In further embodiments, the compliance gradients with varying levels of hardness may be formed by the polymers, nano- or micro-particles.
In some embodiments of the present invention, the wound active agent is silver or a form of silver. Silver is a widely used nonspecific biocidal agent that acts against a very broad spectrum of bacterial species (Yin et al., 1999, J. Burn Care Rehabil. 20:195; herein incorporated by reference in its entirety), yeast species, fungal species (Wright et al., 1999, Am. J Infect. Control 27:344; herein incorporated by reference in its entirety), and viruses (Hussain et al., 1991, Biochem. Biophys. Res. Comm. 189:1444; herein incorporated by reference in its entirety), including several antibiotic resistant strains (Wright et al., 1998, Am. J. Infect. Control 26:572; herein incorporated by reference in its entirety). However, topical silver agents undergo fast inactivation in the wounds because of the highly reactive nature of silver ions. Frequent wound dressings result in large excess of silver being delivered to the wound, resulting in toxic effects from overdose. In vitro studies have shown cytotoxic effects of silver ions on fibroblasts (Poon et al., 2004, Burns 30:140; Hildago et al., Skin Pharmacol. Appl. Skin Physiol. 11:140; each herein incorporated by reference in its entirety), keratinocytes (Poon et al., 2004, Burns 30:140; herein incorporated by reference in its entirety), hepatocytes (Baldi et al., 1988, Toxicol. Lett. 41:261; herein incorporated by reference in its entirety), and lymphocytes (Hussain et al., 1991, Biochem. Biophys. Res. Comm. 189:1444; herein incorporated by reference in its entirety).
The highly reactive nature of silver ions complicates their delivery to wound bed. The released silver ions become rapidly inactive as they readily bind to proteins and chloride within complex wound fluid (Mooney et al., 2006, Plastic and Reconstr. Surg. 117:666; herein incorporated by reference in its entirety), resulting in unwanted adsorption of silver ions in epidermis cells and sweat glands (Klasen, 2000, Burns 26:117; herein incorporated by reference in its entirety). Silver based topical solutions like 0.5% silver nitrate, or ointments like 1% silver sulfadiazine cream, that are currently used in clinics for wound healing, release silver at concentrations up to 3200 ppm but most of this is rapidly inactivated though the formation of chemical complexes in the wound (Dunn et al., Burns, 2004, 30(supplement 1):S1; herein incorporated by reference in its entirety), necessitating frequent applications, up to 12 times a day for silver nitrate solutions and at least twice a day with silver sulfadiazine creams. Frequent dressings result in large excess of silver being delivered to the wound, resulting in toxic effects and discoloration from overdose (Atiyeh et al., 2007, Burns 33:139; Trop et al., 2006, J. Trauma 60:648; each herein incorporated by reference in its entirety). Wound-dressings with silver incorporated into the dressing itself have been recently introduced. They provide prolonged release of silver to the wound, allowing dressings to be changed less frequently. However, these reservoir-dressings have to be impregnated with large amount of silver, which results in cytotoxicity. Silver released from a leading commercial wound-dressing Acticoat™, that contains nanocrystalline silver (Dunn et al., Burns, 2004, 30(supplement 1):51; herein incorporated by reference in its entirety), was shown to be toxic to in vitro monolayer cell cultures of keratinocytes and fibroblasts (Poon et al., 2004, Burns 30:140; Trop et al., 2006, J. Trauma 60:648; each herein incorporated by reference in its entirety). Thus, the challenges with current topical silver antimicrobials lie in their low silver release levels, the lack of penetration, the rapid consumption of silver ions, and the presence of silver nitrate or cream bases that are pro-inflammatory, negatively affecting wound healing. Issues like wound staining, electrolyte imbalance, and patient discomfort also exist.
In certain embodiments, the present invention comprises novel methods for providing controlled and localized loadings of non-cytotoxic levels of antimicrobial silver compositions to surfaces that circumvents using excess-loading of silver in the wound while retaining anti-bacterial activity and reduced cytotoxicity. In experiments conducted during the course of developing certain embodiments of the present invention (Example 13), nanometer-thick polymeric films were assembled that were impregnated with silver nanoparticles to levels resulting in efficient killing of bacteria but no cytotoxic effects on the adherence and growth of mouse fibroblasts cells on the films. In some embodiments, the polymeric films are impregnated with an antimicrobial silver composition by incubating the film in an antimicrobial silver composition as described in Example 13. In other embodiments, the antimicrobial silver composition is directly incorporated into the polymer multilayer during synthesis of the multilayer. See, e.g., Langmuir. 2005 Dec. 6; 21(25):11915-21.
The silver-nanoparticles impregnated thin films of some embodiments of the present invention exploit different principles for delivering silver into the wound-matrix. The films can be applied directly on the exposed wound-bed, allowing them to release the silver ions locally into the wound. This reduces the amount of bactericidal silver needed to impregnate into the film by several orders compared to topical silver delivery agents, significantly reducing the silver-based toxicity. While the present invention is not limited to any particular mechanism, and an understanding of the mechanism is not necessary to practice the present invention, it is contemplated that while silver-impregnated dressings and ointments have to deliver high levels of silver into the wound bed to overcome rapid consumption of silver ions in wound-fluid that limits the penetration of released silver, the localized release of silver right into the wound-matrix by some polymeric thin film embodiments presented herein circumvents the use of large loadings of silver.
Some molecularly-thin composite film embodiments of the present invention can be tuned to contain as low as 0.4 μg/cm²of soluble silver and release a total of less than 1 ppm silver ions in buffers. Such films display 99.9999% bacteria-killing efficiency without any measurable cytotoxicity to mammalian cells. Furthermore, films containing these levels of silver allow adherence and growth of mammalian cells (e.g., NIH-3T3 mouse fibroblasts). In some embodiments, the releasable antimicrobial silver composition is loaded at an amount of from 1 or 10 to about 50, 100, 200, 300, 400, 500 or 1000 μg/cm²of the polymer multilayer and/or releasable in an amount of about 0.01 and 100 μg/cm²of the polymer multilayer per day. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 100 μg/cm²of the polymer multilayer. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 20 μg/cm²of the polymer multilayer. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 5 μg/cm²of the polymer multilayer. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 2 μg/cm²of the polymer multilayer. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.05 and 1 μg/cm²of the polymer multilayer. In some embodiments, the releasable antimicrobial silver composition is releasable in an amount of about 0.1 to 0.5 μg/cm²of the polymer multilayer.
Experiments conducted during the course of developing some embodiments of the present invention allowed systematic variation of the concentration of silver in the films and demonstrated their cytotoxicity and anti-bacterial efficiency to be dependent on the silver-loading. In comparison, the amount of soluble silver in the commercial wound dressing Acticoat™ is ˜100 μg/cm²(Dunn et al., 2004, Burns 30(supplement 1):S1; herein incorporated by reference in its entirety). Acticoat™ releases a total of over 120 ppm silver on dissolution in water for 24 hr (Taylor et al., 2005, Biomaterials 26:7221; herein incorporated by reference in its entirety), and has been shown to be cytotoxic to keratinocytes and fibroblasts (Poon et al., 2005, Burns 30:140; Trop et al., 2006, J. Trauma 60:648; each herein incorporated by reference in its entirety).
Several reports exist on composite films of polyelectrolytes that incorporate silver and display anti-bacterial activity by releasing silver in the solution (Lee et al., 2005, Langmuir 21:9651; Li et al., 2006, Langmuir 22:9820; Grunlan et al., 2005, Biomacromolecules 6:1149; Yu et al., 2007, Bioconj. Chem. 18:1521; Shi et al., 2006, J. Biomed. Mat. Res. Part A 76A:826; each herein incorporated by reference in its entirety). However, all these studies have focused on controlling the volume fraction and concentration of silver in the films. Only films containing high loadings of silver (˜5.5 μg/cm²or more) have been shown to demonstrate anti-bacterial activity (Wang et al., 2002, Langmuir 18:3370; Logar et al., 2007, Nanotechnol. 18:325601; each herein incorporated by reference in its entirety). Such polyelectrolyte films, when loaded with those levels of silver, display strong cytotoxicity and kill 100% NIH-3T3 cells seeded on them (e.g., Example 13).
In experiments conducted during the course of developing certain embodiments of the present invention (e.g., Example 13), loading levels of silver in PEMS were identified and achieved that lead to silver-impregnated antibacterial molecularly-thin films permitting adhesion of mammalian cells without exhibiting cytotoxicity. The films find use for the localized delivery of bactericidal silver to the wounds, reducing risks of toxicity from silver overdose observed with other topical delivery agents. In some embodiments, implantable medical devices can be coated with these silver-impregnated thin films to kill bacteria right during their initial attachment to these surfaces and prevent bacterial colonization, a leading cause of implant failure.
Thus, the silver-releasing moleculary-thin composite films of some embodiments of the present invention have advantage over: 1) other topical delivery agents of silver currently used in clinics; 2) wound-dressings that contain large amounts of silver in them; and 3) other bactericidal composite thin-films containing large amounts of silver, which are cytotoxic to mammalian cells and do not allow mammalian cells to adhere and grow over them.
Using silver-nanoparticle molecularly-thin films for localized delivery of bactericidal silver in wounds can overcome silver-related toxicity encountered with topical silver-delivery agents for wound healing (Poon et al., 2004, Burns 30:140; Baldi et al., 1988, Toxicol. Lett. 41:261; Atiyeh et al., 2007, Burns 33:139; Coombs et al., 1992, Burns 18:179; each herein incorporated by reference in its entirety). Furthermore, these polyelectrolyte multilayers (PEMs) are uniform, highly interpenetrated ultrathin nanocomposite films, typically far less than 1 μm thick (Decher, 1997, Science 277:1232; Hammond, 1999, Curr. Opin. Colloid Interface Sci. 4:430; each herein incorporated by reference in its entirety). Their porous and supramolecular architecture allows incorporating a variety of molecules including DNA, enzymes, viruses, dendrimers, colloids, inorganic particles, and dyes (Decher, 1997, Science 277:1232; herein incorporated by reference in its entirety). Thus, along with delivering bactericidal silver, in some embodiments they can be used for simultaneous localized delivery of other bioactive agents in the wound-matrix (e.g., cell recruiting growth factors, DNA plasmids encoding such growth factors). Since PEMs can conformally coat substrates of any type, size or shape, including natural and synthetic polymers (Hammond, 1999, Curr. Opin. Colloid Interface Sci. 4:430; herein incorporated by reference in its entirety), they can be constructed on any wound-bed or implantable medical device.
In one embodiment, the present invention provides for the deposition and immobilization of cytoactive factors and extracellular matrices (ECMs) on the wound bed by using, for example, polyelectrolyte multilayers or beads. FIG. 1 provides a schematic diagram 100 of a wound bed 110 on which a polyelectrolyte multilayer 130 has been deposited. The diagram 100 depicts that the wound bed 110 comprises a heterogeneous surface depicted by shapes 120 which represent different chemical moieties. The polyelectrolyte multilayer 130 provides a homogenous surface onto which functional groups can 140 can be attached to form a homogenous functionalized surface 150. In the embodiment depicted, the functional groups are uniform, however, in some preferred embodiments, different functional groups are utilized. A wide variety of active agents can then be attached to the surface via the functional groups 140. In other embodiments, the wound bed is covalently modified with covalent modification agents. The covalent modification agents include, but are not limited to, homobifunctional and heterobifunctional cross-linkers as well as photoactivatable cross linkers. FIG. 2 provides a schematic diagram 200 of a wound bed 210 comprising a heterogeneous surface depicted by shapes 220 which represent different chemical moieties. The wound bed is covalently modified by reacting covalent modification agents 230 with the different chemical moieties to provide a relatively homogenous functionalized surface 250. In preferred embodiments, covalent modification agents 230 present functional groups 240. In the embodiment depicted, the functional groups are uniform, however, in some preferred embodiments, different functional groups are utilized. A wide variety of active agents can then be attached to the surface via the functional groups 240. These embodiments are discussed in more detail below.
It is contemplated that the wound bed is an extremely heterogeneous environment. The compositions and methods of the present invention are designed to modify the wound bed to provide a homogenous environment that provides for uniform and predictable delivery or uniform incorporation of active agents into the wound bed. Surprisingly, it has been found that modification of wound beds in this manner greatly reduces the amount of active agent which is needed; i.e., the effective amount of active agent needed is reduced. Surface functionalization allows for precise control of the amount of active agent used or delivered and further allows for the formation of gradients of active agents on the wound bed. In some preferred embodiments, the priming agent is optimized to react with the wound bed. In some embodiments, the priming agent provides an optimized surface for enhanced or optimized delivery of an active agent. In some embodiments, a chemical parameter of the wound bed is changed. For example, the wound bed may be modified to be more or less acidic, basic, alkaline, reducing, or oxidizing or have a higher or lower ionic strength.
There is a wide array of candidate molecules for improving healing chronic wounds. For example, basement membrane constituents and growth factors promote wound healing. In some embodiments, the extracellular matrices deposited and immobilized are constituents of native basement membrane. Native ECMs comprise a mixture of glycoproteins, proteoglycans and hyaluronic acid. These glycoproteins and proteoglycans include, but are not limited to, fibrin, elastin, fibronectin, laminins, glycosaminoglycans, nidogens and collagens. Cytoactive factors such as growth factors are also part of ECMs. In some embodiments, extracellular matrix components, such as collagen, laminin, glycosaminoglycans, or hyaluronic acid are deposited and immobilized on a wound bed. In some embodiments, a synthetic matrix such as MATRIGEL™ is deposited on a wound bed. MATRIGEL™ is a commercially available basement membrane like complex that retains many characteristics of a native basement membrane, including a three-dimensional nanoscale topographic surface. The present invention is not limited to a particular mechanism. Indeed, an understanding of the mechanism is not necessary to practice the present invention. Nonetheless, it is contemplated that the nanoscale topographic features of a basement membrane modulate fundamental cell behaviors including migration, adhesion, proliferation and differentiation (Abrams et al., 2002, Biomimetic Materials and Design: Interactive Biointerfacial, Tissue Engineering, and Drug Delivery, Eds. Dillow and Lowman; Diehl et al., 2005, J. Biomed. Mater. Res. A 75:603; Foley et al., 2005, Biomaterials 26:3639; Karuri et al., 2004, J. Cell Sci. 117:3153; Liliensiek et al., 2006, J. Biomed. Mater. Res. A 79:185). In some embodiments, the present invention further provides methods, formulations, compositions and kits for altering the compliance of the wound surface. In some embodiments, the local compliance (the compliance that cells see) is altered by immobilizing a thin layer of extracellular matrix constituents such as MATRIGEL™ or an appropriate hydrogel or other synthetic matrix or by enzymatic treatment of the wound bed. In other embodiments, compliance is altered by the addition of cross-linking agents to the wound bed to cross-link components already presenting the wound bed, or components deliberately introduced into the wound bed. It has also been demonstrated by Picart and coworkers that it is possible to control the compliance of multilayer structures formed from polyelectrolytes by the addition of cross-linking agents.
In some embodiments, the cytoactive factors that are deposited and immobilized on a wound bed include, but are not limited to, those factors that are mitogenic for epithelial cells and vascular endothelial cells and other factors that are elements in wound closure. For example, in some embodiments, growth factors such as platelet derived growth factor (PDGF), and/or epidermal growth factor (EGF), known to be mitogenic for epithelial cells are deposited in a wound bed. In other embodiments, vascular endothelial growth factor (VEGF), known to be mitogenic for vascular endothelial cells, comprise the cytoactive factors immobilized on the wound bed. It is contemplated that the present invention is not limited by the ECM components or cytoactive factors immobilized on the wound bed, indeed any extracellular matrix components and/or cytoactive factor that improves wound healing is equally applicable. Additional cytoactive and wound active agents that can be incorporated are provided below.

I. Priming the Wound Bed

In some embodiments, the present invention provides compositions and methods for priming the wound bed to provide uniform reactive surface for later modification. Suitable compositions for priming a wound bed include, but are not limited to, polyelectrolytes and chemical crosslinking agents that react covalently with functional groups found in wound beds such as carboxy, thiol, amide and sugar groups.
A. Multilayer Deposition on Wound Bed
In some embodiments, the present invention provides compositions, formulations, methods and kits for depositing a multilayer structure on a wound bed. In some embodiments, the multilayer structures comprise layers of polymers that form polyelectrolytes, while in other embodiments, the multilayers comprise polymers that do not have a charge (i.e., non-ionic polymers) or a combination of charged and uncharged polymer layers. In some embodiments, it is contemplated that polyelectrolyte films built-up by the alternated adsorption of cationic and anionic polyelectrolyte layers constitute a novel and promising technique to modify wound surfaces in a controlled way [(Decher et al., 1992, Thin Solid Films 210/211:831; Decher, 1997, Science 277:1232). One of the most important properties of such multilayers is that they exhibit an excess of alternatively positive and negative charges (Caruso et al., 1999, J Am Chem Soc 121:6039; Ladam et al., 2000, Langmuir 16:1249). Not only can this constitute the motor of their buildup (Joanny, 1999, Eur. Phys. J. Biol. 9:117), but it allows, by simple contact, to adsorb a great variety of compounds such as dyes, particles (Cassagneau et al., 1998, J. Am. Chem. Soc. 120:7848; Caruso et al., 1999, Langmuir 15:8276; Lvov et al., 1997, Langmuir 13:6195), clay microplates (Ariga et al., 1999, Appl. Clay Sci. 15:137) and proteins (Keller et al., 1994, J. Am. Chem. Soc. 116:8817; Lvov et al., 1995, J. Am. Chem. Soc. 117:6117; Caruso et al., 1997, Langmuir 13:3427).
In some embodiments, the polymer multilayers, such as polyelectrolyte multilayers, are nanoscale in dimension. Accordingly, in some embodiments, the polymer multilayers are from about 1 nm to 1000 nm thick, from about 1 nm to 500 nm thick, from about 1 nm to 100 nm thick, from about 1 nm to about 25 nm thick, from about 1 nm to about 10 nm thick, or less than about 500 nm, 100 nm, 25 nm or 10 nm thick. It is contemplated that the nanoscale dimension of the polymer multilayers (i.e., the nanoscale thickness) allows for the loading of a lower total amount of an active agent while still allowing delivery of an effective amount (i.e., an amount of active agent that accelerates wound healing as compared to controls) of the active agent as compared to matrix structures with greater thickness. It is contemplated that the lower total loading levels result in reduced toxicity in the wound environment, especially when antimicrobial compounds are incorporated into the polymer multilayer.
In some embodiments, the compliance of the polymer multilayers is adjusted to facilitate cell migration in the wound. In some embodiments, the polymer multilayers exhibit a compliance, measured in kilopascals (kPa) of from about 3 to about 500 kPa, about 7 to about 250 kPa, about 10 to about 250 kPA or from about 10 to about 200 kPa.
1. Formation of Polyelectrolyte Layers
The cationic polyelectrolyte poly(L-lysine) (PLL) interacts with anionic sites on cell surfaces and in the extracellular matrix (Elbert and Hubbell, 1998, J. Biomed. Mater. Res. 42:55). In some embodiments, the present invention provides a method of treating a wound with the sequential application of a cationic polyelectrolyte, an anionic polyelectrolyte, and a wound active agent to the wound. In other embodiments, the treatment includes the sequential and repeated application of a cationic polyelectrolyte, an anionic polyelectrolyte, and a wound active agent to the wound.
Polyelectrolyte layers are formed by alternating applications of anionic polyelectrolytes and cationic polyelectrolytes to surfaces to form a polyelectrolyte layer. The layers can be used to deliver a wound active agent to a wound. Preferably, at least four layers, and, more preferably, at least six layers are used to form the polyelectrolyte multilayer.
The method of treatment of the present invention is not limited to use on a wound surface. The formation of a polyelectrolyte layer that includes a wound active agent may be formed on any surface to which delivery of a wound active agent is desirable.
In some embodiments, the cationic polyelectrolyte used is PLL and the anionic polyelectrolyte used is poly(L-glutamic acid) (PGA). Indeed, the use of a variety of polyelectrolytes is contemplated, including, but not limited to, poly(ethylene imine) (PEI), poly(allylamine hydrochloride) (PAH), poly(sodium 4-styrenesulfonate) (PSS), poly(acrylic acid) (PAC), poly(maleic acid-co-propylene) (PMA-P), poly(acrylic acid) (PAA), and poly(vinyl sulfate) (PVS). It is also possible to use naturally occurring polyelectrolytes, including hyaluronic acid and chondroitin sulfate.
In still further embodiments, the polymer is a dendrimer, grafted polymer, or star architecture polymer. In other embodiments, the multilayer responds to or is organized in the presence of an electric field, for example an electric field formed by placing electrodes on either side of a wound.
Referring to FIG. 1, in some embodiments, the polymer multilayer 130 can be comprised of polystyrene sulfonate, an amphiphillic polyelectrolyte with an affinity for hydrophobic regions of the wound bed, and an amphoteric polymer. The polymer multilayer is preferably functionalized with one or more crosslinking agents presenting an alkyne so that a uniform surface is presented (e.g., 140 in FIG. 1 where x represents an alkyne group). From this point, widely available click chemistries can be used to add desired wound active agents to the modified surface of the wound. In some embodiments, the wound modifying agent is an azide conjugate or otherwise comprises an azide group and is reacted with the alkyne groups displayed on the wound bed in a Huisgen Cycloaddition.
Other suitable methods for preparing polyelectrolyte multilayers include those described, for example, in Cho and Char, Langmuir 20:4011-4016, 2004; Okamura et al., Adv. Mater. 21, 4388-92 (2009), Cho et al., Adv. Mat. 13(14):1076-1078 (2001); and U.S. pat. Publ. 2010/0062258; the entire contents of each of which is incorporated herein by reference. Suitable methods include layer by layer deposition, formation on SAMs, and spin coating assisted assembly.
2. Cationic Polymers
Cationic polymers useful in the present invention can be any biocompatible water-soluble polycationic polymer, for example, any polymer having protonated heterocycles attached as pendant groups. As used herein, “water soluble” means that the entire polymer must be soluble in aqueous solutions, such as buffered saline or buffered saline with small amounts of added organic solvents as co-solvents, at a temperature between 20 and 37° Centigrade. In some embodiments, the material will not be sufficiently soluble (defined herein as soluble to the extent of at least one gram per liter) in aqueous solutions per se but can be brought into solution by grafting the polycationic polymer with water-soluble polynonionic materials such as polyethylene glycol.
Representative cationic polymers include natural and unnatural polyamino acids having net positive charge at neutral pH, positively charged polysaccharides, and positively charged synthetic polymers. Examples of suitable polycationic materials include polyamines having amine groups on either the polymer backbone or the polymer side chains, such as poly-L-lysine (PLL) and other positively charged polyamino acids of natural or synthetic amino acids or mixtures of amino acids, including, but not limited to, poly(D-lysine), poly(ornithine), poly(arginine), and poly(histidine), and nonpeptide polyamines such as poly(aminostyrene), poly(aminoacrylate), poly (N-methyl aminoacrylate), poly (N-ethylaminoacrylate), poly(N,N-dimethyl aminoacrylate), poly(N,N-diethylaminoacrylate), poly(aminomethacrylate), poly(N-methyl amino-methacrylate), poly(N-ethyl aminomethacrylate), poly(N,N-dimethyl aminomethacrylate), poly(N,N-diethyl aminomethacrylate), poly(ethyleneimine), polymers of quaternary amines, such as poly(N,N,N-trimethylaminoacrylate chloride), poly(methyacrylamidopropyltrimethyl ammonium chloride), and natural or synthetic polysaccharides such as chitosan. In some embodiments, PLL is a preferred material.
In general, the polymers must include at least five charges, and the molecular weight of the polycationic material must be sufficient to yield the desired degree of binding to a tissue or other surface, having a molecular weight of at least 1000 g/mole.
3. Anionic Polymers
Polyanionic materials useful in the present invention can be any biocompatible water-soluble polyanionic polymer, for example, any polymer having carboxylic acid groups attached as pendant groups. Suitable materials include alginate, carrageenan, furcellaran, pectin, xanthan, hyaluronic acid, heparin, heparan sulfate, chondroitin sulfate, dermatan sulfate, dextran sulfate, poly(meth)acrylic acid, oxidized cellulose, carboxymethyl cellulose and crosmarmelose, synthetic polymers and copolymers containing pendant carboxyl groups, such as those containing maleic acid or fumaric acid in the backbone. Polyaminoacids of predominantly negative charge are also suitable. Examples of these materials include polyaspartic acid, polyglutamic acid, and copolymers thereof with other natural and unnatural amino acids. Polyphenolic materials such as tannins and lignins can be used if they are sufficiently biocompatible. Preferred materials include alginate, pectin, carboxymethyl cellulose, heparin and hyaluronic acid.
4. Nonionic Polymers
In some embodiments, the multilayer structures are formed from uncharged polymers or from a combination of charged and uncharged polymers. Examples of uncharged polymers include, but are not limited to, dextran, dextran sulfate, diethylaminoethyl (DEAE)-dextran, hydroxyethyl cellulose, ethyl(hydroxyethyl) cellulose, acrylamide, polyethylene oxide, polypropylene oxide, polyethylene oxide-polypropylene oxide copolymers, PAAN_a, Ficoll, polyvinylpyrolidine, and polyacrylic acid.
5. Amphoteric Polymers
In some embodiments, the multilayer structures are formed from one or more amphoteric polymers, alone in combination with the other polymers described herein. In some embodiments, the amphoteric polymers comprise one or more of acrylic acid (AA), DMAEMA (dimethylaminoethyl methacrylate), APA (2-aminopropyl acrylate), MorphEMA (morpholinoethyl methacrylate), DEAEMA (diethylaminoethyl methacrylate), t-ButylAEMA (t-butylaminoethyl methacrylate), PipEMA (piperidinoethyl methacrylate), AEMA (aminoethyl methacrylate), HEMA (2-hydroxyethyl methacrylate), MA (methyl acrylate), MAA (methacrylic acid) APMA (2-aminopropyl methacrylate), AEA (aminoethyl acrylate). In some embodiments, the amphoteric polymer comprises (a) carboxylic acid, (b) primary amine, and (c) secondary and/or tertiary amine. The amphoteric polymers have an isoelectric point of 4 to 8, preferably 5 to 7 and have a number average molecular weight in the range of 10,000 to 150,000.
6. Application of Multilayers
The wound modifying agent, such as a polymer multilayer, can be applied to the wound by a variety of methods. In some embodiments, it is contemplated that the polymer or polymer multilayers, is applied, preferably sequentially, to the wound using either a pump (including syringes, ink jet printers, and electrojets) or aerosol spray. In other embodiments, particle bombardment is utilized. In other embodiments, the use of a brush including an air brush is contemplated. In other embodiments, a sponge is utilized. In other embodiments a solid support or stamp such as an elastomeric material, for example, PDMS (polydimethylsiloxane), silicone, hydrogel or latex, is used to support the wound modifying agents and mechanically transfer the agent into the wound bed. In these embodiments, the polymer multilayers are pre-formed on the stamp. In further embodiments, nano- or micro-particles are arranged on the stamp for delivery to the wound. In other approaches, electric fields or magnetic fields are used to facilitate transfer of the wound modifying agents into the wound bed.
In some embodiments, the polymers are applied to a wound by a spray, such as via a pump or aerosol device. In some embodiments, the polymer layers are applied sequentially. In one embodiment, a solution, dispersion, or suspension of the wound modifying agent and wound active agent is sprayed onto the wound to form the polyelectrolyte layer. In embodiments where the wound modifying agent and wound active agent are supplied as aerosols, a propellant is used to provide the force for expulsion from the container. In some embodiments, the wound modifying agent or the wound active agent and the propellant form a single liquid phase so that the composition is delivered consistently.
In general, for aerosol delivery, the ingredients of the composition are mixed to form a substantially homogenous solution, slurry, dispersion, or the like. For two-part systems, each part is mixed. The compositions are placed in an appropriate container and the propellant is added using conventional techniques, such as cold filling or pressure filling techniques. The composition can be delivered using a commercially available aerosol sprayer such as, for example, the Preval™ aerosol spray unit available from Precision Valve Corporation, NY, USA, which has a modular power unit and refillable container jar. The propellant is a mixture of propane, isobutane, and dimethyl ether.
The composition can also be delivered using a syringe outfitted with a spray head, or a dual spray device outfitted with a spray head and, optionally, a mixing chamber. The device may include a meter so that the quantity of applied composition can be controlled.
Any of a number of propellants known to those skilled in the art can be used, provided that it is chemically inert to the other ingredients of the composition. Suitable propellants include vinyl chloride and mixtures of vinyl chloride and dichlorodifluoromethane, other fluorochlorohydrocarbons known as the Freons and the Genetrons, and blends of fluorochlorohydrocarbons, chlorinated hydrocarbons, and hydrocarbons. Examples of fluorochlorohydrocarbons include trichloromonofluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, 2-tetrafluoroethane, 1,1-dichloro-1,2,2-tetraf-luoroethane, 1-chloro-1,1-difluoroethane, 1,1-difluoroethane, and octofluorocyclobutane, and mixtures thereof. Examples of hydrocarbons include liquefied petroleum gases like propane, isobutane, and N-butane and mixtures thereof. Dimethyl ether is another propellant. Compressed gas propellants that are preferably non-toxic, non-flammable, and inert can be used. Examples include carbon dioxide, nitrous oxide and N₂and the like. Mixtures of the above are often used.
The quantity of propellant used is critical only in that if an insufficient amount is used, the driving force to expel the entire composition from the container will be lacking Generally, the composition will comprise from 75% to 95% by weight propellant.
In some embodiments, the invention contemplates a kit comprising a container with a cationic polyelectrolyte, a second container containing an anionic polyelectrolyte, and a third container containing at least one wound active agent. In still other embodiments, in addition to a container with a cationic polyelectrolyte, a second container containing an anionic polyelectrolyte, and a third container containing at least one wound active agent, the kit provides an application device for administering the polyelectrolytes and at least one wound active agent to the wound. In some preferred embodiments, the containers comprise a propellant. In other embodiments, the containers comprise a pump.
In some embodiments, contacting comprises delivery of the polymer and the at least one wound active agent to the wound using a reaction chamber dressing (RCD). In some embodiments, it is contemplated that the RCD will comprise a solid barrier adhered to an area completely surrounding the wound. Within the solid barrier reside inflow and outflow orifices to which tubes from solution reservoirs can be connected. The use of a variety of solid barriers is contemplated, including, but not limited to, Gortex, latex, Teflon, PVDF, plastic and rubber.
In some embodiments, the wound modification agents are applied to the wound by microfluidics printing, microstamping (U.S. Pat. Nos. 5,512,131 and 5,731,152, both of which are incorporated by reference herein in their entirety), or microcontact printing (PCT Publication WO 96/29629, incorporated by reference herein in its entirety). In other embodiments, the wound modifying agents are applied to the wound via a pulse jet such as an inkjet printer. Examples of suitable inkjet printers for application of biological fluids include those described in U.S. Pat. No. 7,128,398, WO 95/25116 and WO 98/41531, each of which is incorporated by reference in its entirety. In other embodiments, the wound modifying agents are applied by a drop dispensers such as the tip of a pin or in an open capillary and, touch the pin or capillary to the surface of the substrate. Such a procedure is described in U.S. Pat. No. 5,807,522. When the fluid touches the surface, some of the fluid is transferred. In other embodiments, the wound modifying agents are applied be pipetting, micro-pipetting or positive displacement pumps such as the Biodot equipment (available from Bio-Dot Inc., Irvine Calif., USA).
One or more wound active agents are preferably applied to the wound along with the wound modification agent. In some embodiments, the wound active agent is covalently attached to the wound modification agent. In other embodiments, the wound active agent is incorporated into the wound modifying agent, for example, by application during sequential application of polymer layers in a polymer multilayer. In other embodiments, the wound active agents are delivered by a microarrayer, pipette, positive displacement pump, inkjet printer, microneedle array, elastomeric stamp, gene gun, electrojet, or air brush as described above in relation to the wound modifying agents.
B. Modification of Wound Beds with Biocompatible Particles
In some embodiments, the wound modifying agent is a nano- or micro-particle. In some embodiments, nanometer to submicrometer sized biocompatible particles, such as spherical (e.g., beads) and/or non-spherical (e.g., oblongs, needles, cubes, tetrahedral, mushroom-like structures, haybale-like structures) particles or electrospun polymers, are applied (e.g., either directly or indirectly) to the wound bed, thereby creating a three-dimensional topographic wound bed. For example, application of biocompatible particles to a wound bed results in the creation of knobs, ridges, spikes, undulations, and the like in the wound bed. Microbeads have a size generally ranging from about 1 to about 500 micrometers, while nanobeads have a size generally ranging from about 1 to about 1000 nanometers. Microbeads may further comprise micro- (i.e., from 1 to 100 micrometers) or nano-scale (0.1 to 1000 nanometer) features on the surface of the bead. Nanobeads may further comprise nanoscale features (i.e., 0.1 to 500 nanometer features) on the surface of the bead. In some embodiments, a wound active agent is present in the form of a bead or particle, such as silver nanoparticles.
In some embodiments, the biocompatible particles are biodegradable. In some embodiments, the biocompatible particles are not biodegradable. The biocompatible particles, for example, are modified with surface chemistry cross-linkers that allow attachment and immobilization of wound active agents, extracellular matrix compounds, polyelectrolytes, etc. as described further herein. It is contemplated that the incorporation of modified biocompatible particles, for example, facilitates the presentation of ECM constituents that support epithelial coverage of the wound, provides cytoactive factors for wound healing, and introduces topographic features that support cellular behaviors for promoting wound healing. In some embodiments, the biocompatible particles are functionalized with mesoscopic cross-linkers to, for example, broadly enable covalent chemistry in the wound bed. In some embodiments, cross-linkers are attached to negatively charged biocompatible particles. In some embodiments, the biocompatible particles comprise layers of multiple different constituents for wound healing, or a single constituent for wound healing. For example, spherical particles such as beads placed in a wound bed comprise, or upon which are layered, one or more intermixed species of polyelectrolytes, ECM agents, proteins with hydrolysable bonds, proteins with enzymatically cleavable bonds, and the like for wound healing as previously described. In some embodiments, antimicrobials, either alone or in combination with other wound healing compositions, are also applied to the biocompatible particles. Antimicrobials include, but are not limited to, antibiotics, metal based antimicrobial compositions comprising silver (e.g., ionic silver, elemental silver, silver nanoparticles), copper, selenium, triclosan-based antimicrobials, thiabendazole-based antimicrobials, isothiazolinone-based antimicrobials, zinc-pyrithione-based antimicrobials, and/or 10′-oxybisphenoxarsine-based antimicrobials (OBPA). The present invention is not limited by the type of antimicrobial used.
In some embodiments, the size of the biocompatible particles, such as beads, are at least 1 nm, at least 5 nm, at least 10 nm, at least 20 nm, at least 50 nm, at least 100 nm, at least 200 nm, at least 300 nm, at least 500 nm, or at least 800 nm in diameter. In some embodiments, beads and other spherical and non-spherical particles contain their own surface topography. For example, the bead surface may comprise undulations, indentations, tunnels, holes, knobs, ridges, etc. Spherical particles, such as beads, may or may not be inert and may, for example, be magnetic. Magnetic beads comprise, for example, a magnetic core or magnetic particles. Examples of different bead compositions are found at, for example, U.S. Pat. Nos. 5,268,178, 6,458,858, 6,869,858, and 5,834,121, each of which is incorporated herein by reference in its entirety.
In some embodiments, biocompatible particles of the present invention used for wound healing are coated with layers of polyelectrolytes, ECM components, antimicrobials, proteins with hydrolysable bonds, proteins with enzymatically cleavable bonds, etc. and other wound healing compositions wherein the surface compliance of the beads is maintained for optimal wound healing. For example, the compliance of the layers for wound healing as deposited on the biocompatible particles are contemplated to be of optimal stiffness (e.g., not too soft, not too hard) such that cells within the wound bed are capable of optimal anchorage and spreading. Engler et al. (2004, Biophys. J. 86:617-628) discusses substrate compliance for cell anchorage and spreading. In some embodiments, the biocompatible particles are layered with polyelectrolytes, ECM components, antimicrobials, etc. wherein substrate stiffness of at least 1 kPa, at least 5 kPa, at least 8 kPa, at least 10 kPa, at least 20 kPa, at least 40 kPa, at least 60 kPa, at least 80 kPa is realized as measured using the methods of Engler et al. (2004). In preferred embodiments, substrate compliance of the wound healing compositions as applied to biocompatible particles is at least 8 kPa to about 80 kPa or 100 kPa. It will be recognized that hardness within these limit are contemplated without specifically listing all such hardnesses, for example, 10, 20, 30, 40, 50, 60, or 70 kPa limits as upper or lower ranges are all contemplated by the present invention. In some embodiments, the ECM composition preferentially used in conjunction with polyelectrolytes, antimicrobials, and other wound healing compositions is collagen.
In some embodiments, the layers as applied to a wound bed or to a biocompatible particle comprise gradients of wound healing compositions, for example, wound active agents. For example, the concentrations of the compositions are layered in a wound bed or on a biocompatible particle in a gradient such that higher concentrations of a particular composition is greater proximal to the wound bed than distal to the wound bed in a vertical fashion. The converse, where concentrations of compositions is greater distal to the wound bed than proximal, is also contemplated. Concentration of compositions in a wound bed or on a biocompatible particle wherein a horizontal gradient is deposited is also contemplated. Topographical gradients are also contemplated, wherein compositions are deposited such that the concentrations of compositions in a wound bed or on a biocompatible particle follow the topography of the substrate, for example, a higher concentration of compositions is deposited in the valleys of undulations of an exemplary substrate compared to the peaks of the undulations. Likewise, the present invention contemplates that compliance gradients can be formed in the wound bed by controlled application of micro- or nano-beads of varying hardness. For example, beads having one, two, three, four or more different hardnesses are applied to form a vertical gradient (i.e., a depth gradient) on the wound or a horizontal gradient (i.e., a gradient along the length or width of the wound), or a combination of vertical and horizontal gradients. Horizontal and vertical gradients can also be formed with beads functionalized with 1, 2, 3, 4 or more different wound active agents. See Ichinose et al., Biomaterials. Volume 27, Issue 18, June 2006, Pages 3343-3350; Stefonek et al., Immobilized gradients of epidermal growth factor promote accelerated and directed keratinocyte migration. Wound Repair and Regeneration (OnlineEarly Articles). doi:10.1111/j.1524-475X.2007.00288.x; Kapur et al., Immobilized concentration gradients of nerve growth factor guide neurite outgrowth. Journal of Biomedical Materials Research Part A. Volume 68A, Issue 2, Pages 235-243; DeLong et al., Covalently immobilized gradients of bFGF on hydrogel scaffolds for directed cell migration. Biomaterials 26 (2005) 3227-3234; Liu, et al., 2007 Sep. 25; 17892312 Endothelial Cell Migration on Surface-Density Gradients of Fibronectin, VEGF, or Both Proteins.
In some embodiments, wound healing compositions applied to the wound bed or biocompatible particles (e.g., beads, needles, etc.) are time released, such that wound healing compositions that are applied to the wound bed or biocompatible particles are released over a period of time, for example 3 hours, 5 hours, 10 hours, 1 day, several days, one week, several weeks, etc. thereby providing short and/or long term treatment for the wound bed.
In some embodiments, biocompatible particles used in wound bed healing applications of the present invention are not, for example, spherical as previously described, but take on shapes such as oblongs, needles, mushroom-like structures, haybale-like structures, etc. In some embodiments, the biocompatible particle shape is preferably needles. The manufacture of needles useful in embodiments of the present invention can be accomplished through microfabrication techniques, such as those found in, for example, McAllister et al., 2003, Proc. Natl. Acad. Sci. 100:13755-13760. In some embodiments, biocompatible particles are coated and/or layered with wound healing compositions, anti-microbials, proteins that are hydrolyzably cleavable, proteins that are enzymatically cleavable, antimicrobials, etc. as described herein. In some embodiments, the coated and/or layered biocompatible particles are applied to a wound bed by stamping, spraying, or other methods as described herein.
In some embodiments, the layers of wound healing compositions as described herein are deposited on a wound bed or on biocompatible particles by electrostatic bonding. In other compositions, non-electrostatic interactions are utilized, such as van der Waals interactions, metal ion-ligand coordination or hydrogen bonding. In some embodiments, the layers of wound healing compositions as described herein are deposited by piezoelectric application, using methods and systems as described in, for example, U.S. Pat. No. 6,368,079 and Sumerel et al., 2006, Biotechnol. J. 1:976-987. In other embodiments, the wound healing compositions are directly or indirectly deposited into the wound bed by using electrojetting technologies, including electroextrusion, and electrospraying and electrospinning. In some embodiments, the layers deposited comprise one or more wound healing compositions. In some embodiments, the layers are biocompatible particles (e.g. spherical beads, needles, and the like) intermixed with wound healing compositions. In other embodiments, layered deposition is sequential. For example, sequential deposition of wound healing compositions alone, or sequential deposition of wound healing compositions followed by biocompatible particles, followed by wound healing compositions, etc. The present invention is not limited by the constituents that make up a layer of deposition on a biocompatible particle, and many permutations of wound healing compositions and biocompatible particle layering would be apparent to a skilled artisan.
In some embodiments, the deposition of layers in the wound bed or on a biocompatible particle or other substrate to be added to a wound bed is accomplished by “stamping”, also referred to as “contact printing”. A stamp substrate is any substrate that can be used to transfer one or more than one entity or composition (e.g., polyelectrolytes, ECM components, proteins with hydrolysable or enzymatically cleavable bonds, etc.) that is (are) covalently or non-covalently bound to the surface of the stamp substrate to another surface. Examples of suitable stamp substrates include, but are not limited to, polydimethylsiloxane (PDMS) and other elastomeric (e.g., pliable) materials. In some embodiments, different concentrations of the same wound healing composition are arrayed in different areas of the stamp substrate. In other embodiments, a variety of different compositions are arrayed on the stamp substrate surface. In some embodiments, multiple wound healing compositions in multiple concentrations are arrayed on the stamp substrate surface. The wound healing compositions are then introduced to the stamp substrate surface, which are in turn stamped into the wound bed or onto another substrate for introduction into the wound bed (e.g., biocompatible particles).
In other embodiments, the biocompatible particles, for example needles, are coated and/or layered with wound healing compositions, anti-microbials, proteins that are hydrolyzably cleavable, proteins that are enzymatically cleavable, etc., and applied to a pad which is subsequently applied to a wound. Pads include, but are not limited to, band-aids, gauze, surgical packings, and the like. In some embodiments, the pad is impregnated with wound healing compositions, anti-microbials, proteins that are hydrolyzably cleavable, proteins that are enzymatically cleavable, etc. In some embodiments, the biocompatible particles (e.g., covered and/or layered with wound healing compositions, anti-microbials, proteins that are hydrolyzably cleavable, proteins that are enzymatically cleavable, etc.) are affixed in a detachable or non-detachable manner to the pad prior to applying the pad to a wound. In some embodiments, when the pad is removed from the wound the biocompatible particles are retained (e.g., not detached) on the pad, whereas in other embodiments when the pad is removed from the wound the nanostructures are retained (e.g., detached) in the wound bed. For example, a pad is impregnated with compositions as described and further affixed with biocompatible particles that are themselves coated and/or layered with compositions as described for wound healing. The pad with biocompatible particles is applied to the wound and while the pad is superficial to the wound bed, the biocompatible particles thereon reach down in proximity with the wound bed as compared to the location of the pad. The pad releases (e.g., either over a short period of time or in a time-release manner) the impregnated wound healing compositions on or near the surface of the wound whereas the affixed biocompatible particles release the coated and/or layered wound healing compositions (e.g., either over a short period of time or in a time-release manner) more proximal to the wound bed. Alternatively, a pad with affixed biocompatible particles (both pad and nanostructures comprising wound healing compositions as previously described) is first applied to a wound bed. The pad is subsequently removed; however the detachable biocompatible particles remain in the wound bed. The pad serves not only to deliver wound healing compositions to a wound bed, but further serves a purpose of delivering biocompatible particles, such as needles, into a wound bed. The biocompatible particles left in the wound bed, for example, continue releasing wound healing compositions to the wound bed for further healing. In some embodiments, a new (e.g., second, third, fourth, etc.) pad comprising impregnated wound healing compositions as previously described is re-applied to the wound wherein resides the biocompatible particles retained by the original application of the first pad/nanostructure. The application of the new pad, for example, serves not only to impart fresh wound healing compositions to a wound but also serves to recoat the biocompatible particles with fresh would healing compositions that are released (e.g., either over a short period of time or in a time-release manner) proximal to the wound bed.
The present invention is not limited to a particular mechanism. Indeed, an understanding of the mechanism is not necessary to practice the present invention. Nonetheless, it is contemplated that the negatively charged macromolecular species and beads do not readily pass across cell membranes, and therefore serve as a non-toxic means of wound bed healing. As well, the size of the beads used determines the nanostructure of the wound bed, thereby allowing for personalized wound bed healing therapies. FIG. 6 provides an exemplary embodiment of the use of beads for wound bed healing. However, the present invention is not limited by the size of bead, the reactive groups found on the beads (e.g., carboxylic acid groups, thiol groups, amine groups, etc.), the cross-linkers used, or the cytoactive factors and other wound healing compositions that are associated with the beads. Indeed, a myriad of combinations of compounds (e.g., small molecule, peptides, proteins, drugs, etc) for wound healing is contemplated for use with beads applied to a wound bed.
In some embodiments, the particles modulate a wound response following an application of an electric or magnetic field to the wound bed. Accordingly, in some embodiments, the particles are charged or magnetized so that the particles migrate or reorganize in an electric or magnetic field. In other embodiments, the beads are dielectric so that the beads experience dielectrophoresis in an AC electrical field. In other embodiments, the beads are magnetic and migrate and/or transmit mechanical forces when exposed to a magnetic field. In other embodiments, the beads are charged so that mechanical forces are applied to the wound bed when an electric field is applied, for example, by placing electrodes on either side of a wound.
In some embodiments, the nano- or micro-beads are applied to the wound by microfluidics printing, microstamping (U.S. Pat. Nos. 5,512,131 and 5,731,152, both of which are incorporated by reference herein in their entirety), or microcontact printing (PCT Publication WO 96/29629, incorporated by reference herein in its entirety). In other embodiments, the nano- or micro-beads are applied to the wound via a pulse jet such as an inkjet printer. Examples of suitable inkjet printers for application of biological fluids include those described in U.S. Pat. No. 7,128,398, WO 95/25116 and WO 98/41531, each of which is incorporated by reference in its entirety. In other embodiments, the nano- or micro-beads are applied by drop dispensers such as the tip of a pin or in an open capillary tube and, touch the pin or capillary tube to the surface of the substrate. Such a procedure is described in U.S. Pat. No. 5,807,522. When the fluid touches the surface, some of the fluid is transferred. In other embodiments, the wound modifying agents are applied be pipetting, micro-pipetting or positive displacement pumps such as the Biodot equipment (available from Bio-Dot Inc., Irvine Calif., USA). In still other embodiments, the nano- or micro-beads are applied to the wound via a microneedle array.
C. Modification with Covalent Modifiers
In some embodiments, the present invention provides for the covalent immobilization of factors to the wound bed. In some preferred embodiments, the covalent modification occurs via homobifunctional or heterobifunctional linkers. In some embodiments, the covalent modifiers are used to directly modify the wound bed by covalently attaching the wound bed. In some embodiments, the covalent modifiers are used to covalently attach 1, 2, 3, 4 or more different wound active agents to the wound bed. In some embodiments, the covalent modifiers are used to establish gradients of the 1, 2, 3, 4 or more different wound active agents in a vertical or horizontal plane with respect to the wound. In some embodiments, the covalent modifiers are used in conjunction with the polymer layers or beads describes above. In some embodiments, the covalent modifies are used to attach wound active agents to the polymer layers or beads, while in other embodiments, the covalent modifies are used to cross link the polymers or beads.
In some embodiments, the present invention provides methods of treatment, comprising providing a subject having a wound, at least one covalent modification agent and at least one wound active agent, and contacting the wound with the at least one covalent modification agent and the at least one wound active agent under conditions such that the at least one wound active agent is covalently attached to the wound. In some embodiments, the subject is a human. In other embodiments, the subject is a non-human vertebrate. In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker. In other embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker. For example, in some embodiments, the homobifunctional cross-linker is an N-hydroxysuccinimidyl ester (e.g., including, but not limited to, disuccinimidyl ester, dithiobis(succinimidylpropionate), 3,3′-dithiobis(sulfosuccinimidylpropionate), disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, disuccinimidyl tartarate, disulfosuccinimidyl tartarate, bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone, bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone, ethylene glycolbis(succinimidylsuccinate), ethylene glycolbis(sulfosuccinimidylsuccinate), disuccinimidyl glutarate, and N,N′-disuccinimidylcarbonate). In some embodiments, the homobifunctional cross-linker is at a concentration between 1 nanomolar and 10 millimolar. In some preferred embodiments, the homobifunctional cross-linker is at a concentration between 10 micromolar and 1 millimolar. In other embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker (e.g., including, but not limited to, N-succinimidyl 3-(2-pyridyldithio)propionate, succinimidyl 6-(3-[2-pyridyldithio]-propionamido)hexanoate, sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido)hexanoate, succinimidyloxycarbonyl-α-methyl-α-(2-pyridyldithio)toluene, sulfosuccinimidyl-6-[α-methyl-α-(2-pyridyldithio)toluamido]hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, m-maleimidobenzoyl-N-hydroxysuccinimide ester, m-maleimidobenzoyl-N-hydroxy-sulfosuccinimide ester, N-succinimidyl(4-iodoacetyl)aminobenzoate, sulfo-succinimidyl(4-iodoacetyl)aminobenzoate, succinimidyl-4-(p-maleimidophenyl)butyrate, sulfosuccinimidyl-4-(p-maleimidophenyl)butyrate, N-(γ-maleimidobutyryloxy)succinimide ester, N-(γ-maleimidobutyryloxy)sulfosuccinimide ester, succinimidyl 6-((iodoacetyl)amino)hexanoate, succinimidyl 6-(6-(((4-iodoacetyl)amino)hexanoyl)amino)hexanoate, succinimidyl 4-(((iodoacetyl)amino)methyl)cyclohexane-1-carboxylate, succinimidyl 6-((((4-iodoacetyl)amino)methyl)cyclohexane-1-carbonyl)amino)-hexanoate, and p-nitrophenyl iodoacetate). In some embodiments, the heterobifunctional cross-linker is modified with functional groups, rendering it soluble in aqueous solvents for delivery as an aqueous solution. Furthermore, in some embodiments, the aqueous solution contains additives (e.g., including, but not limited to, surfactants and block copolymers). In other embodiments, a multiplicity of heterobifunctional cross-linkers can be attached to a molecule, polymer or particle to serve as the cross-linking agent. In other embodiments, the heterobifunctional cross-linker is dissolved in an organic solvent (e.g., including, but not limited to, dimethyl sulfoxide). In some embodiments, the at least one wound active agent includes, but is not limited to, trophic factors, extracellular matrices, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents (including but not limited to silver (e.g., ionic silver, elemental silver, silver nanoparticles)), buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents. In some embodiments, the at least one wound active agent contains one or more free —SH groups.
In some embodiments, the covalent modifier is a photoactivatable crosslinker. Suitable photoactivatable crosslinkers include, but are not limited to, aryl azide N-((2-pyridyldithio)ethyl)-4-azidosalicylamide, 4-azido-2,3,5,6-tetrafluorobenzoic acid, succinimidyl ester, 4-azido-2,3,5,6-tetrafluorobenzoic acid, STP ester, benzophenone maleimide, succinimidyl ester of 4-benzoylbenzoic acid, N-5-Azido-2-Nitrobenzoyloxysuccinimide, N-Hydroxysulfosuccinimidyl-4-azidobenzoate, N-Hydroxysuccinimidyl-4-azidosalicylic acid, and (4-[p-Azidosalicylamido]butylamine).
Referring again to FIG. 2, spatial heterogeneity is depicted in a wound by shapes 720 which depict different chemical moieties found in a wound beds such as amine groups and sulfhydryl groups. Typical areas in a wound will be amine and or sulfhydryl-rich. In some embodiments, a crosslinker (e.g., 230 in FIG. 2) comprising an activated acid is used to react with amine groups, for example nHS (n-hydroxysuccimydal) and a second crosslinker (e.g., 235 in FIG. 2) comprising a malemide is used to react with sulfhydryl groups. In some embodiments, the malimide and activated acid are conjugated to an alkyne so that a uniform surface is presented (e.g., 240 in FIG. 2 where x represents an alkyne group). From this point, widely available click chemistries can be used to add desired wound active agents to the modified surface of the wound. In some embodiments, the wound modifying agent is an azide conjugate or otherwise comprises an azide group and is reacted with the alkyne groups displayed on the wound bed in a Huisgen Cycloaddition.
The present invention also provides kits for treating a subject having a wound, comprising at least one covalent modification agent, at least one wound active agent, and instructions for using the kit to covalently link the at least one wound active agent to the wound. In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker, heterobifunctional crosslinker, or photoactivatable crosslinker as described above. In some embodiments, the at least one wound active agent includes, but is not limited to wound active agents described in detail below.
The present invention also provides a kit for treating a subject having a wound, comprising at least one covalent modification agent, at least one wound active agent, and instructions for using the kit to covalently link the at least one wound active agent to the wound. In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker. In some embodiments, the homobifunctional cross-linker is an N-hydroxysuccinimidyl ester (e.g., including, but not limited to, disuccinimidyl ester, dithiobis(succinimidylpropionate), 3,3′-dithiobis(sulfosuccinimidylpropionate), disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, disuccinimidyl tartarate, disulfosuccinimidyl tartarate, bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone, bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone, ethylene glycolbis(succinimidylsuccinate), ethylene glycolbis(sulfosuccinimidylsuccinate), disuccinimidyl glutarate, and N,N′-disuccinimidylcarbonate). In some embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker (e.g., including, but not limited to, N-succinimidyl 3-(2-pyridyldithio)propionate, succinimidyl 6-(3-[2-pyridyldithio]-propionamido)hexanoate, sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido)hexanoate, succinimidyloxycarbonyl-α-methyl-α-(2-pyridyldithio)toluene, sulfosuccinimidyl-6-[α-methyl-α-(2-pyridyldithio)toluamido]hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, m-maleimidobenzoyl-N-hydroxysuccinimide ester, m-maleimidobenzoyl-N-hydroxy-sulfosuccinimide ester, N-succinimidyl(4-iodoacetyl)aminobenzoate, sulfo-succinimidyl(4-iodoacetyl)aminobenzoate, succinimidyl-4-(p-maleimidophenyl)butyrate, sulfosuccinimidyl-4-(p-maleimidophenyl)butyrate, N-(γ-maleimidobutyryloxy)succinimide ester, N-(γ-maleimidobutyryloxy)sulfosuccinimide ester, succinimidyl 6-((iodoacetyl)amino)hexanoate, succinimidyl 6-(6-(((4-iodoacetyl)amino)hexanoyl)amino)hexanoate, succinimidyl 4-(((iodoacetyl)amino)methyl)cyclohexane-1-carboxylate, succinimidyl 6-((((4-iodoacetyl)amino)methyl)cyclohexane-1-carbonyl)amino)-hexanoate, and p-nitrophenyl iodoacetate). In some embodiments, the at least one wound active agent includes, but is not limited to, trophic factors (including polypetide growth factors, neuropeptides, neurotrophins, extracellular matrices and their individual native constituents (exemplified by but not limited to laminin, fibronectin, vitronectin, collagens, also select amino acid sequences found in these proteins known to promote cell behaviors favorable to wound healing e.g. integrin binding sequences exemplified by but not limited to RGD, EILDV, VCAM-1 and their recombined or synthetic analogs, enzymes, enzyme inhibitors, polypeptides, antimicrobial peptides (exemplified by but not limited to defensins, magaignins, cathelocidins, bactenicin) anti-infective agents (including but not limited to silver (e.g., ionic silver, elemental silver, silver nanoparticles)), buffering agents, vitamins and minerals, compounds that promote generation/stabilization of nitic oxide, energy sources for cells, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents. In other embodiments the kits include small interfering RNAs (siRNAs—also referred to as micro RNAs) that are capable of promoting cellular behaviors conducive to the wound healing process. In other embodiments, the kits include compounds that promote/stabilize a favorable pH, osmotic environment, surface energy, surface charge, surface functionalities that enhance galvano and magneto positive effects on wound healing, or balance of MMP/other peptidase/protease activity (i.e. inhibitors/promoters).
II. Wound Active Agents
In some embodiments, wound active agents are delivered to a wound bed or incorporated into a wound bed using the systems described above. In some embodiments, the wound active agent is bound covalently or non-covalently with the polyelectrolyte layer, bead, non-covalent modifier, etc. The present invention is not limited to a particular mechanism by which the wound active agent binds to the polyelectrolyte layer, bead, non-covalent modifier, etc.
In some embodiments, the polyelectrolyte layer, beads, or non-covalent modifier may function as a drug delivery scaffold to deliver one or more wound active agents to the wound. Wound active agents that may be desirable to deliver include, but are not limited to, trophic factors, extracellular matrices (ECMs), ECM fragments or synthetic constructs, enzymes, enzyme inhibitors, defensins, polypeptides, anti-infective agents (including antimicrobials, antivirals and antifungals), buffering agents, vitamins and minerals, analgesics, anticoagulants, coagulation factors, anti-inflammatory agents, vasoconstrictors, vasodilators, diuretics, and anti-cancer agents. In addition, would active agents include iodine based antimicrobials such as PVP-iodine; selenium based antimicrobials such as 7-azabenzisoselenazol-3(2H)-ones, selenium disulfide, and selenides; and silver based antimicrobials (e.g., silver sulfadiazine, ionic silver, elemental silver, silver nanoparticles)). With respect to selenides, with the use of standard and variations of typical protein and carbohydrate attachment chemistries, carboxyl and amino containing selenides may be routinely attached to many polymers, peptides, antibodies, steroids and drugs. Polymers and other molecules with attached selenides generate superoxide in a dose dependent manner in biological solutions, in cells or attached to insoluble matrixes such as silicones.
A wide variety of wound active agents can be incorporated into the polyelectrolyte layer, beads, or covalent or non-covalent modifier. The present invention is not limited to a particular mechanism by which one or more wound active agents are released from the polyelectrolyte layer, beads, or covalent or non-covalent modifier into the wound. Indeed, an understanding of the mechanism is not necessary to practice the present invention. Nonetheless, in some embodiments, the present invention contemplates release of the one or more incorporated agents from the polyelectrolyte layer, beads, or non-covalent modifier to the wound by diffusion from the polyelectrolyte layer. In other embodiments, the one or more wound active agents may be released from the polyelectrolyte layer, beads, or non-covalent modifier over time or in response to an environmental condition. The one or more wound active agents may be attached by a degradable linkage, such as a linkage susceptible to degradation via hydrolysis or enzymatic degradation. The linkage may be one that is susceptible to degradation at a certain pH, for example.
In some embodiments, the one or more wound active agents are applied to form a gradient with respect to the wound modifying agent. In general, the gradients present a higher contraction of wound active agent at one or more first desired locations in the wound following application of the wound modifying agent to the wound and a lower concentration of wound active agent at one or second location in the wound following application of the wound modifying agent to the wound. For example, the concentrations of the wound active agents are layered in a wound bed in a gradient such that higher concentrations of a particular composition is greater proximal to the wound bed than distal to the wound bed in a vertical fashion. The converse, where concentrations of compositions is greater distal to the wound bed than proximal, is also contemplated. Concentration of compositions in a wound bed wherein a horizontal gradient is deposited is also contemplated. Topographical gradients are also contemplated, wherein compositions are deposited such that the concentrations of compositions in a wound bed or on a biocompatible particle follow the topography of the substrate, for example, a higher concentration of compositions is deposited in the valleys of undulations of an exemplary substrate compared to the peaks of the undulations.
In some embodiments, the gradient comprises a higher concentration of the wound active agent in the center of the wound modifying agent which transitions to a lower concentration of the wound active agent away from the center of the wound modifying agent. Accordingly, when the wound modifying agent is applied to a wound, the gradient results in a higher concentration of wound active agent in the center of the wound and a lower concentration of wound active agent as one moves to the periphery of the wound. In some embodiments, the gradient comprises a lower concentration of the wound active agent in the center of the wound modifying agent which transitions to a higher concentration of the wound active agent away from the center of the wound modifying agent. Accordingly, the gradient results in a lower concentration of wound active agent in the center of the wound and a higher concentration of wound active agent as one moves to the periphery of the wound. If two or more wound active agents are utilized, they can be presented as similar gradients or the gradients can be varied so that the concentrations of the two or more wound active agents vary across the wound. The gradients of high or low concentration can be any shape, such as circular, square, rectangular, oval, oblong, etc. so that the matrix and gradient can conform to a variety of wound shapes. For example, for long, incision type wound, the gradient may be centered on a longitudinal axis that extends along the length of the wound and can be centered on the wound. As another example, the gradient can be circular or oval-shaped for application to open type wounds, burns, sores and ulcers that are roughly circular or oval. In other embodiments, the gradients comprise a series of features arranged in a pattern. For example, the gradients can form a series of stripes or high and low concentrations of one or more wound active agents along a longitudinal axis of the matrix. Alternatively, the gradients can form a checkerboard pattern, array, concentric circles, overlapping circles or oval, etc.
The present invention contemplates delivery of a wide variety of wound active agents to the wound. In some embodiments, the present invention provides the delivery of trophic factors, including, but not limited to, agrin, amphiregulin, artemin, cardiotrophin-1, epidermal growth factors including EGF; fibroblast growth factors (e.g., FGF-1, FGF-2, FGF-3, FGF-4, FGF-5, FGF-6, and FGF-7); LIF, CSF-1, CSF-2, CSF-3, erythropoietin, endothelial cell growth factors including ECGF; FGF- and ECGF-related growth factors (e.g., endothelial cell stimulating angiogenesis factor, tumor angiogenesis factor, retina-derived growth factor (RDGF), vascular endothelium growth factor (VEGF), brain-derived growth factors (BDGF-A and B), astroglial growth factors (AGF 1 and 2), omentum-derived growth factor, fibroblast-stimulating factor (FSF), and embryonal carcinoma-derived growth factor (ECDGF)); neurotrophic growth factors (e.g, nerve growth factors (NGFs), neurturin, brain-derived neurotrophic factor (BDNF), neurotrophin-3, neurotrophin-4, and ciliary neurotrophic factor (CNTF)); glial growth factors (e.g., GGF-I, GGF-II, GGF-III, glia maturation factor (GMF), and glial-derived neurotrophic factor (GDNF)); liver growth factors (e.g., hepatopoietin A, hepatopoietin B, and hepatocyte growth factors including HGF); prostate growth factors including prostate-derived growth factors (PGFs); mammary growth factors including mammary-derived growth factor 1 (MDGF-1) and mammary tumor-derived factor (MTGF); heart growth factors including nonmyocyte-derived growth factor (NMDGF); melanocyte growth factors including melanocyte-stimulating hormone (MSH) and melanoma growth-stimulating activity (MGSA); angiogenic factors (e.g., angiogenin, angiotropin, platelet-derived ECGF, VEGF, and pleiotrophin); transforming growth factors including TGF-α and TGF-β; TGF-like growth factors (e.g., TGF-beta₁, TGF-beta₂, TGF-beta₃, GDF-1, CDGF, tumor-derived TGF-like factors, ND-TGF, and human epithelial transforming factor); regulatory peptides with growth factor-like properties (e.g., bombesin and bombesin-like peptides ranatensin and litorin, angiotensin, endothelin, atrial natriuretic factor, vasoactive intestinal peptide, and bradykinin); platelet-derived growth factors including PDGF-A, PDGF-B, and PDGF-AB; neuropeptides (e.g., substance P, calcitonin gene-regulated peptide (CGRP), and neuropeptide Y); neurotransmitters and their analogs including norepinephrine, acetylcholine and carbachol; hedgehog, heregulin/neuregulin, IL-1, osteoclast-activating factor (OAF), lymphocyte-activating factor (LAF), hepatocyte-stimulating factor (HSF), B-cell-activating factor (BAF), tumor inhibitory factor 2 (TIF-2), keratinocyte-derived T-cell growth factor (KD-TCGF), IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, stromal cell-derived cytokine (SCDC), IL-12, IL-13, IL-14, IL-15, insulin, insulin-like growth factors including IGF-1, IGF-2, and IGF-BP; interferons including INF-alpha, INF-beta, and INF-gamma; leptin, midkine, tumor necrosis factors (TNF-alpha and beta), netrins, saposins, semaphorins, somatrem, somatropin, stem cell factor, VVGF, bone morphogenetic proteins (BMPs), adhesion molecules, other cytokines, heparin-binding growth factors, and tyrosine kinase receptor ligands. In some embodiments, the wound active agent is a peptide such as AcEEED, which is the N terminal peptide for alpha smooth muscle actin and has been shown to inhibit contractile properties of myofibroblasts.
In some embodiments, the present invention provides the delivery of ECMs, including, but not limited to native constructs, fragments of native constructs and synthetic analogs of: extracellular matrix proteins, reconstituted basement membrane-like complexes derived from eukaryotic cell lines, collagens, fibronectin, laminin, VCAM-1, vitronectin and gelatin, a bacterial extracellular matrix, a gel matrix, and polymeric matrices. In some embodiments, the wound active agents are integrin binding sequences exemplified by, but not limited to RGD, EILDV, VCAM-1 and their recombined or synthetic analogs, enzymes, enzyme inhibitors, and polypeptides.
In some embodiments, the present invention provides the delivery of enzymes, including, but not limited to, exopeptidases and endopeptidases (also known as proteases and proteinases), including but not limited to the serine proteinases chymotrypsin, trypsin, elastase, and kallikrein, bacterial enzymes, the cysteine proteases papain, actinin, bromelain, cathepsins, cytosolic calpains, parasitic proteases, aspartic proteinases, the pepsin family of proteases pepsin and chymosin, lysosomal cathepsins D, renin, fungal proteases, the viral proteases, AIDS virus retropepsin, and the metalloproteinases (MMPs), collagenases, Maggott enzyme, MMP1, MMP2, MMP8, MMP13, gelatinases, MMP2, MMP9, MMP3, MMP7, MMP10, MMP11, and MMP12.
In some embodiments, the present invention provides the delivery of enzyme inhibitors, including, but not limited to captopril, thiorphan, phosphoramidon, teprotide, protease and proteinase inhibitors, metalloproteinase inhibitors and exopeptidase inhibitors.
In some embodiments, the present invention provides the delivery of defensins, including, but not limited to, alpha- defensins HNP 1, 2, 3 and 4, and beta-defensins HBD-1 and HBD-2.
In some embodiments, the present invention provides the delivery of polypeptides, including, but not limited to, fibronectin, serotonin, PAF, PDEGF, TNFa, IL1, IL6, IGF, IGF-1, IGF-2, IL-1, PDGF, FGF, KGF, VEGF, bradykinin, prothymosin-alpha, and thymosin-alpha1.
In some embodiments, the present invention provides the delivery of antimicrobials, including, but not limited to, magainin (e.g., magainin I, magainin II, xenopsin, xenopsin precursor fragment, caerulein precursor fragment), magainin I and II analogs (e.g., PGLa, magainin A, magainin G, pexiganin, Z-12, pexigainin acetate, D35, MSI-78A, MGO (K10E, K11E, F12W-magainin 2), MG2+(K10E, F12W-magainin-2), MG4+(F12W-magainin 2), MG6+(f12W, E19Q-magainin 2 amide), MSI-238, reversed magainin II analogs (e.g., 53D, 87-ISM, and A87-ISM), Ala-magainin II amide, magainin II amide), cecropin P1, cecropin A, cecropin B, indolicidin, nisin, ranalexin, lactoferricin B, poly-L-lysine, cecropin A (1-8)-magainin II (1-12), cecropin A (1-8)-melittin (1-12), CA(1-13)-MA(1-13), CA(1-13)-ME(1-13), gramicidin, gramicidin A, gramicidin D, gramicidin S, alamethicin, protegrin, histatin, dermaseptin, lentivirus amphipathic peptide or analog, parasin I, lycotoxin I or II, globomycin, gramicidin S, surfactin, ralinomycin, valinomycin, polymyxin B, PM2 ((+/−) 1-(4-aminobutyl)-6-benzylindane), PM2c ((+/−)-6-benzyl-1-(3-carboxypropyl)indane), PM3 ((+/−)1-benzyl-6-(4-aminobutyl)indane), tachyplesin, buforin I or II, misgurin, melittin, PR-39, PR-26, 9-phenylnonylamine, (KLAKKLA)n, (KLAKLAK)n, where n=1, 2, or 3, (KALKALK)3, KLGKKLG)n, and KAAKKAA)n, wherein N=1, 2, or 3, paradaxin, Bac 5, Bac 7, ceratoxin, mdelin 1 and 5, bombin-like peptides, PGQ, cathelicidin, HD-5, Oabac5alpha, ChBac5, SMAP-29, Bac7.5, lactoferrin, granulysin, thionin, hevein and knottin-like peptides, MPG1, 1bAMP, snakin, lipid transfer proteins, and plant defensins. Exemplary sequences for the above compounds are provided in Table 1. In some embodiments, the antimicrobial peptides are synthesized from L-amino acids, while in other embodiments, the peptides are synthesized from, or comprise, D-amino acids. Additional antimicrobial polypeptides of use in the present invention are listed in FIG. 7.

TABLE 1

Antimicrobial Peptides

SEQ ID NO:	Name	Organism	Sequence

1	lingual antimicrobial	Bos taurus	mrlhhlllallflvlsagsgftqgvrnsqscrrnkgicvp
	peptide precursor		ircpgsmrqigtclgaqvkccrrk
	(Magainin)

2	antimicrobial	Xenopus laevis	gvlsnvigylkklgtgalnavlkq
	peptide PGQ

3	Xenopsin	Xenopus laevis	mykgiflcvllavicanslatpssdadedndeveryvrgw
			askigqtlgkiakvglkeliqpkreamlrsaeaqgkrpwil

4	magainin precursor	Xenopus laevis	mfkglficsliavicanalpqpeasadedmderevrgigk
			flhsagkfgkafvgeimkskrdaeavgpeafadedldere
			vrgigkflhsakkfgkafvgeimnskrdaeavgpeafade
			dlderevrgigkflhsakkfgkafvgeimnskrdaeavgp
			eafadedlderevrgigkflhsakkfgkafvgeimnskrd
			aeavgpeafadedfderevrgigkflhsakkfgkafvgei
			mnskrdaeavgpeafadedlderevrgigkflhsakkfgk
			afvgeimnskrdaeavddrrwve

5	tachyplesin I	Tachypleus	kwcfrvcyrgicyrrcr
		gigas

6	tachyplesin II	Tachypleus	rwcfrvcyrgicyrkcr
		gigas

7	buforin I	Bufo bufo	msgrgkqggkvrakaktrssraglqfpvgrvhrllrkgny
		gagarizans	aqrvgagapvylaavleyltaeilelagnaardnkktrii
			prhlqlavrndeelnkllggvtiaqggvlpniqavllpkt
			esskpaksk

8	buforin II	Bufo bufo	trssraglqfpvgrvhrllrk
		gagarizans

9	cecropin A	Bombyx mori	mnfvrilsfvfalvlalgavsaapeprwklfkkiekvgrn
			vrdglikagpaiavigqakslgk

10	cecropin B	Bombyx mori	mnfakilsfvfalvlalsmtsaapeprwkifkkiekmgrn
			irdgivkagpaievlgsakaigk

11	cecropin C	Drosophila	mnfykifvfvalilaisigqseagwlkklgkrierigqht
		melanogaster	rdatiqglgiaqqaanvaatarg

12	cecropin P1	Sus scrofa	swlsktakklensakkrisegiaiaiqggpr

13	indolicidin	Bos taurus	ilpwkwpwwpwrr

14	nisin	Lactococcus	itsislctpgcktgalmgcnmktatchcsihvsk
		lactis

15	ranalexin	Rana	flgglikivpamicavtkkc
		catesbeiana

16	lactoferricin B	Bos taurus	fkcrrwqwrmkklgapsitcvrraf

17	protegrin-1	Sus scrofa	rggrlcycrrrfcvcvgrx

18	protegrin-2	Sus scrofa	ggrlcycrrrfcicvg

19	histatin	Homo sapiens	mkffvfalilalmlsmtgadshakrhhgykrkfhekhhsh
	precursor		rgyrsnylydn

20	histatin 1	Macaca	dsheerhhgrhghhkygrkfhekhhshrgyrsnylydn
		fascicularis

21	dermaseptin	Phyllomedusa	alwktmlkklgtmalhagkaalgaaadtisqtq
		sauvagei

22	dermaseptin 2	Phyllomedusa	alwftmlkklgtmalhagkaalgaaantisqgtq
		sauvagei

23	dermaseptin 3	Phyllomedusa	alwknmlkgigklagkaalgavkklvgaes
		sauvagei

24	misgurin	Misgurnus	rqrveelskfskkgaaarrrk
		anguilli-
		caudatus

25	melittin	Apis mellifera	gigavlkvlttglpaliswisrkkrqq

26	pardaxin-1	Pardachirus	gffalipkiissplfktllsavgsalsssgeqe
		pavoninus

27	pardaxin-2	Pardachirus	gffalipkiisspifktllsavgsalsssggqe
		pavoninus

28	bactenecin 5	Bos taurus	metqraslslgrcslwllllglvlpsasaqalsyreavlr
	precursor		avdqfnersseanlyrlleldptpnddldpgtrkpvsfrv
			ketdcprtsqqpleqcdfkenglvkqcvgtvtldpsndqf
			dincnelqsvrfrppirrppirppfyppfrppirppifpp
			irppfrpplgpfpgrr

29	bactenecin precursor	Bos taurus	metpraslslgrwslwllllglalpsasaqalsyrealvr
			avdqlneqssepniyrlleldqppqddedpdspkrvsfrv
			ketvcsrttqqppeqcdfkenglarcegtvtldqvrgnf
			ditcnnhqsiritkqpwappqaarlcrivvirvcr

30	ceratotoxin A	Ceratitis	sigsalkkalpvakkigkialpiakaalp
		capitata

31	ceratotoxin B	Ceratitis	sigsafkkalpvakkigkaalpiakaalp
		capitata

32	cathelicidin	Homo sapiens	mktqrnghslgrwslvllllglvmplaiiaqvlsykeavl
	antimicrobial		raidginqrssdanlyrlldldprptmdgdpdtpkpvsft
	peptide		vketvcprttqqspedcdfkkdglvkrcmgtvtlnqargs
			fdiscdkdnkrfallgdffrkskekigkefkrivqrikdf
			lrnlvprtes

33	myeloid cathelicidin	Equus caballus	metqrntrclgrwsplllllglvippattqalsykeavlr
	3		avdglnqrssdenlyrlleldplpkgdkdsdtpkpvsfmv
			ketvcprimkqtpeqcdfkenglvkqcvgtvildpvkdyf
			dascdepqrvkrfhsvgsliqrhqqmirdkseatrhgiri
			itrpklllas

34	myeloid	Bos taurus	metqraslslgrwslwllllglalpsasaqalsyreavlr
	antimicrobial		avdqlneksseanlyrlleldpppkeddenpnipkpvsfr
	peptide BMAP-28		vketvcprtsqqspeqcdfkengllkecvgtvtldqvgsn
			fditcavpqsvgglrslgrkilrawkkygpiivpiirig

35	myeloid cathelicidin	Equus caballus	metqrntrclgrwsplllllglvippattqalsykeavlr
	1		avdglnqrssdenlyrlleldplpkgdkdsdtpkpvsfmv
			ketvcprimkqtpeqcdfkenglvkqcvgtvilgpvkdhf
			dvscgepqrvkrfgrlaksflrmrillprrkillas

36	SMAP 29	Ovis aries	metqraslslgrcslwllllglalpsasaqvlsyreavlr
			aadqlneksseanlyrlleldpppkqddensnipkpvsfr
			vketvcprtsqqpaeqcdfkengllkecvgtvtldqvrnn
			fditcaepqsvrglrrlgrkiahgvkkygptvlriiriag

37	BNP-1	Bos taurus	rlcrivvirvcr

38	HNP-1	Homo sapiens	acycripaciagerrygtciyqgrlwafcc

39	HNP-2	Homo sapiens	cycripaciagerrygtciyqgrlwafcc

40	HNP-3	Homo sapiens	dcycripaciagerrygtciyqgrlwafcc

41	HNP-4	Homo sapiens	vcscrlvfcrrtelrvgncliggvsftycctrv

42	NP -1	Oryctolagus	vvcacrralclprerragfcrirgrihplccrr
		cuniculus

43	NP-2	Oryctolagus	vvcacrralclplerragfcrirgrihplccrr
		cuniculus

44	NP-3A	Oryctolagus	gicacrrrfcpnserfsgycrvngaryvrccsrr
		cuniculus

45	NP-3B	Oryctolagus	grcvcrkqllcsyrerrigdckirgvrfpfccpr
		cuniculus

46	NP-4	Oryctolagus	vsctcrrfscgfgerasgsctvnggvrhtlccrr
		cuniculus

47	NP-5	Oryctolagus	vfctcrgflcgsgerasgsctingvrhtlccrr
		cuniculus

48	RatNP-1	Rattus	vtcycrrtrcgfrerlsgacgyrgriyrlccr
		norvegicus

49	Rat-NP-3	Rattus	cscrysscrfgerllsgacrlngriyrlcc
		norvegicus

50	Rat-NP-4	Rattus	actcrigacvsgerltgacglngriyrlccr
		norvegicus

51	GPNP	Guinea pig	rrcicttrtcrfpyrrlgtcifqnrvytfcc

52	beta defensin-3	Homo sapiens	mrihyllfallflflvpvpghggiintlqkyycrvrggrc
			avlsclpkeeqigkcstrgrkccrrkk

53	theta defensin-1	Macaca mulatta	rcictrgfcrclcrrgvc

54	defensin CUA1	Helianthus	mkssmkmfaalllvvmcllanemggplvveartcesqshk
		annuus	fkgtclsdtncanvchserfsggkcrgfrrcfctthc

55	defensin SD2	Helianthus	mkssmkmfaalllvvmcllanemggplvveartcesqshk
		annuus	fkgtclsdtncanvchserfsggkergfrrcfctthc

56	neutrophil defensin	Macaca mulatta	acycripaclagerrygtcfymgrvwafcc
	2

57	4 KDA defensin	Androctonus	gfgcpfnqgachrhcrsirrrggycaglfkqtctcyr
		australis
		hector

58	defensin	Mytilus	gfgcpnnyqchrhcksipgrcggycggxhrlrctcyrc
		gallop-
		rovincialis

59	defensin AMP1	Heuchera	dgvklcdvpsgtwsghcgssskcsqqckdrehfayggach
		sanguinea	yqfpsvkcfckrqc


60	defensin AMP1	Clitoria	nlcerasltwtgncgntghcdtqcrnwesakhgachkrgn
		ternatea	wkcfcyfnc

61	cysteine-rich	Mus musculus	mkklvllfalvllafqvqadsiqntdeetkteeqpgekdq
	cryptdin-1 homolog		avsvsfgdpqgsalqdaalgwgrrcpqcprcpscpscprc
			prcprckcnpk

62	beta-defensin-9	Bos taurus	qgvrnfvtcrinrgfcvpircpghrrqigtclgpqikccr

63	beta-defensin-7	Bos taurus	qgvrnfvtcrinrgfcvpircpghrrqigtclgprikccr

64	beta-defensin-6	Bos taurus	qgvrnhvtcriyggfcvpircpgrtrqigtcfgrpvkccrrw

65	beta-defensin-5	Bos taurus	qvvrnpqscrwnmgvcipiscpgnmrqigtcfgprvpccr

66	beta-defensin-4	Bos taurus	qrvrnpqscrwnmgvcipflcrvgmrqigtcfgprvpccrr

67	beta-defensin-3	Bos taurus	qgvrnhvtcrinrgfcvpircpgrtrqigtcfgprikccrsw

68	beta-defensin-10	Bos taurus	qgvrsylscwgrgicllnrcpgrmrqigtclaprvkccr

69	beta-defensin-13	Bos taurus	sgisgplscgrnggvcipircpvpmrqigtcfgrpvkccrsw

70	beta-defensin-1	Bos taurus	dfaschtnggiclprn-cpghmiqigicfrprvkccrsw

71	coleoptericin	Zophobas	slqggapnfpqpsqqnggwqvspdlgrddkgntrgqieiq
		atratus	nkgkdhdfnagwgkvirgpnkakptwhvggtyrr

72	beta defensin-3	Homo sapiens	mrihyllfallflflvpvpghggiintlqkyycrvrggrc
			avlsclpkeeqigkcstrgrkccrrkk

73	defensin C	Aedes aegypti	atcdllsgfgvgdsacaahciargnrggycnskkvcvcrn

74	defensin B	Mytilus edulis	gfgcpndypchrhcksipgryggycggxhrlrctc

75	sapecin C	Sarcophaga	atcdllsgigvqhsacalhcvfrgnrggyctgkgicvcrn
		peregrina

76	macrophage	Oryctolagus	mrtlallaaillvalqaqaehvsysidevvdqqppqaedq
	antibiotic	cuniculus	dvaiyvkehessalealgvkagvvcacrralclprerrag
	peptide MCP-1		fcrirgrihplccrr

77	cryptdin-2	Mus musculus	mkplvllsalvllsfqvqadpiqntdeetkteeqsgeedq
			avsvsfgdregaslqeeslrdlvcycrtrgckrrermngt
			crkghlmytlcc

78	cryptdin-5	Mus musculus	mktfvllsalvllafqvqadpihktdeetnteeqpgeedq
			avsisfggqegsalheelskklicycrirgckrrervfgt
			crnlfltfvfccs

79	cryptdin 12	Mus musculus	lrdlvcycrargckgrermngtcrkghllymlccr

80	defensin	Pyrrhocoris	atcdilsfqsqwvtpnhagcalhcvikgykggqckitvchcrr
		apterus

81	defensin R-5	Rattus	vtcycrstrcgfrerlsgacgyrgriyrlccr
		norvegicus

82	defensin R-2	Rattus	vtcscrtsscrfgerlsgacrlngriyrlcc
		norvegicus

83	defensin NP-6	Oryctolagus	gicacrrrfclnfeqfsgycrvngaryvrccsrr
		cuniculus

84	beta-defensin-2	Pan	mrvlyllfsflfiflmplpgvfggisdpvtclksgaichp
		troglodytes	vfcprrykqigtcglpgtkcckkp

85	beta-defensin-2	Homo sapiens	mrvlyllfsflfiflmplpgvfggigdpvtclksgaichp
			vfcprrykqigtcglpgtkcckkp

86	beta-defensin-1	Homo sapiens	mrtsylllftlclllsemasggnfltglghrsdhyncvss
			ggqclysacpiftkiqgtcyrgkakcck

87	beta-defensin-1	Capra hircus	mrlhhlllvlfflvlsagsgftqgirsrrschrnkgvcal
			trcprnmrqigtcfgppvkccrkk

88	beta defensin-2	Capra hircus	mrlhhlllalfflvlsagsgftqgiinhrscyrnkgvcap
			arcprnmrqigtchgppvkccrkk

89	defensin-3	Macaca	mrtlvilaaillvalqaqaeplqartdeataaqeqiptdn
		mulatta	pevvvslawdeslapkdsvpglrknmacycripaclager
			rygtcfylgrvwafcc

90	defensin-1	Macaca	mrtlvilaaillvalqaqaeplqartdeataaqeqiptdn
		mulatta	pevvvslawdeslapkdsvpglrknmacycripaclager
			rygtcfylgrvwafcc

91	neutrophil defensin	Mesocricetus	vtcfcrrrgcasrerhigycrfgntiyrlccrr
	1	auratus

92	neutrophil defensin	Mesocricetus	cfckrpvcdsgetqigycrlgntfyrlccrq
	1	auratus

93	Gallinacin 1-alpha	Gallus gallus	grksdcfrkngfcaflkcpyltlisgkcsrfhlcckriw

94	defensin	Allomyrina	vtcdllsfeakgfaanhslcaahclaigrrggscergvcicrr
		dichotoma

95	neutrophil cationic	Cavia	rrcicttrtcrfpyrrlgtcifqnrvytfcc
	peptide 1	porcellus

In some embodiments, the present invention provides the delivery of antimicrobials, including, but not limited to, loracarbef, cephalexin, cefadroxil, cefixime, ceftibuten, cefprozil, cefpodoxime, cephradine, cefuroxime, cefaclor, neomycin/polymyxin/bacitracin, dicloxacillin, nitrofurantoin, nitrofurantoin macrocrystal, nitrofurantoin/nitrofuran mac, dirithromycin, gemifloxacin, ampicillin, gatifloxacin, penicillin V potassium, ciprofloxacin, enoxacin, amoxicillin, amoxicillin/clavulanate potassium, clarithromycin, levofloxacin, moxifloxacin, azithromycin, sparfloxacin, cefdinir, ofloxacin, trovafloxacin, lomefloxacin, methenamine, erythromycin, norfloxacin, clindamycin/benzoyl peroxide, quinupristin/dalfopristin, doxycycline, amikacin sulfate, vancomycin, kanamycin, netilmicin, streptomycin, tobramycin sulfate, gentamicin sulfate, tetracyclines, framycetin, minocycline, nalidixic acid, demeclocycline, trimethoprim, miconazole, colistimethate, piperacillin sodium/tazobactam sodium, paromomycin, colistin/neomycin/hydrocortisone, amebicides, sulfisoxazole, pentamidine, sulfadiazine, clindamycin phosphate, metronidazole, oxacillin sodium, nafcillin sodium, vancomycin hydrochloride, clindamycin, cefotaxime sodium, co-trimoxazole, ticarcillin disodium, piperacillin sodium, ticarcillin disodium/clavulanate potassium, neomycin, daptomycin, cefazolin sodium, cefoxitin sodium, ceftizoxime sodium, penicillin G potassium and sodium, ceftriaxone sodium, ceftazidime, imipenem/cilastatin sodium, aztreonam, cinoxacin, erythromycin/sulfisoxazole, cefotetan disodium, ampicillin sodium/sulbactam sodium, cefoperazone sodium, cefamandole nafate, gentamicin, sulfisoxazole/phenazopyridine, tobramycin, lincomycin, neomycin/polymyxin B/gramicidin, clindamycin hydrochloride, lansoprazole/clarithromycin/amoxicillin, alatrofloxacin, linezolid, bismuth subsalicylate/metronidazole/tetracycline, erythromycin/benzoyl peroxide, mupirocin, fosfomycin, pentamidine isethionate, imipenem/cilastatin, troleandomycin, gatifloxacin, chloramphenicol, cycloserine, neomycin/polymyxin B/hydrocortisone, ertapenem, meropenem, cephalosporins, fluconazole, cefepime, sulfamethoxazole, sulfamethoxazole/trimethoprim, neomycin/polymyxin B, penicillins, rifampin/isoniazid, erythromycin estolate, erythromycin ethylsuccinate, erythromycin stearate, ampicillin trihydrate, ampicillin/probenecid, sulfasalazine, sulfanilamide, sodium sulfacetamide, dapsone, doxycycline hyclate, trimenthoprim/sulfa, methenamine mandelate, plasmodicides, pyrimethamine, hydroxychloroquine, chloroquine phosphate, trichomonocides, anthelmintics, atovaquone, bacitracin, bacitracin/polymyxin b, gentamycin, neomycin/polymyxin/dexameth, neomycin sulf/dexameth, sulfacetamide/prednisolone, sulfacetamide/phenylephrine, tobramycin sulfate/dexameth, bismuth tribromophenate, silver ion compounds, silver nanoparticles, zerovalent silver, multivalent silver, elemental silver, and silver containing compounds such as silver sulfadiazine and related compounds.
In some embodiments, the present invention provides the delivery of antivirals, including, but not limited to, amantadine, acyclovir, foscarnet, indinavir, ribavirin, enfuvirtide, emtricitabine, lamivudine, abacavir sulfate, fomivirsen, valacyclovir, tenofovir, cidofovir, atazanavir, amprenavir, delavirdine mesylate, famciclovir, adefovir, didanosine, efavirenz, trifluridine, inidinavir, lamivudine, vidarabine, lopinavir/ritonavir, ganciclovir, zanamivir, abacavir/lamivudine/zidovudine, lamivudine/zidovudine, nelfinavir, nelfinavir mesylate, nevirapine, ritonavir, saquinavir, saquinavir mesylate, rimantadine, stavudine, docosanol, zalcitabine, idoxuridine, zidovudine, zidovudine/didanosine, valganciclovir, penciclovir, lamivudine, and oseltamivir.
In some embodiments, the present invention provides the delivery of antifungals, including, but not limited to, amphotericin B, nystatin, nystatin/triamcinolone, itraconazole, ketoconazole, miconazole, sulconazole, clotrimazole, clotrimazole/betamethasone, enilconazole, econazole, oxiconazole, tioconazole, terconazole, butoconazole, thiabendazole, flucytosine, butenafine, ciclopirox, haloprogin, naftifine, tolnaftate, natamycin, undecylenic acid, mafenide, dapsone, clioquinol, clioquinol/hydrocortisone, potassium iodide, silver sulfadiazine, gentian violet, carbol-fuchsin, cilofungin, sertaconazole, voriconazole, fluconazole, terbinafine, caspofungin, other topical azole drugs, and griseofulvin.
In some embodiments, the present invention provides the use and delivery of buffering agents, including, but not limited to, Maleic acid, Phosphoric acid, Glycine, Chloroacetic acid, Formic acid, Benzoic acid, Acetic acid, Pyridine, Piperazine, MES, Bis-tris, Carbonate, ACES, ADA MOPSO, PIPES, Phosphoric acid, BES, MOPS, TES, HEPES, DIPSO, TAPSO, Triethanolamine, HEPSO, Tris, Tricine, Bicine, TAPS, Borate, Ammonia, CHES, Ethanolamine, CAPSO, Glycine, Carbonate, CAPS, Methylamine, Piperidine, and Phosphoric acid.
In some embodiments, the present invention provides the delivery of vitamins and minerals, including, but not limited to, Vitamin A, Carotenoids, Vitamin D, Vitamin E, Vitamin K, Vitamin C/ascorbic acid, B1/thiamin, B2/riboflavin, B3/niacin, B5/pantothenic acid, B6/pyridoxine, B12/cobalamin, Biotin, Calcium, Magnesium, Phosphorus, Sodium, Chloride, Potassium, Boron, Chromium, Copper, Iodine, Iron, Manganese, Selenium, and Zinc.
In some embodiments, the present invention provides the delivery of analgesics, including, but not limited to, acetaminophen, anileridine, acetylsalicylic acid, buprenorphine, butorphanol, fentanyl, fentanyl citrate, codeine, rofecoxib, hydrocodone, hydromorphone, hydromorphone hydrochloride, levorphanol, alfentanil hydrochloride, meperidine, meperidine hydrochloride, methadone, morphine, nalbuphine, opium, levomethadyl, hyaluronate sodium, sufentanil citrate, capsaicin, tramadol, leflunomide, oxycodone, oxymorphone, celecoxib, pentazocine, propoxyphene, benzocaine, lidocaine, dezocine, clonidine, butalbital, phenobarbital, tetracaine, phenazopyridine, sulfamethoxazole/phenazopyridine, and sulfisoxazole/phenazopyridine.
In some embodiments, the present invention provides the delivery of anticoagulants, including, but not limited to, coumarins, 1,3-indandione, anisindione, fondaparinux, heparin, lepirudin, antithrombin, warfarin, enoxaparin, dipyridamole, dalteparin, ardeparin, nadroparin, and tinzaparin.
In some embodiments, the present invention provides the delivery of coagulation factors, including, but not limited to, Factor I (fibrinogen), Factor II (prothrombin), Factor III (thromboplastin, tissue factor), Factor IV (calcium), Factor V (labile factor), Factor VII (stable factor), Factor VIII (antihemophilic globulin, antihemophilic globulin, antihemophilic factor A), Factor IX (plasma thromboplastin component, Christmas factor, antihemophilic factor B), Factor X (Stuart factor, Prower factor, Stuart-Prower factor), Factor XI (plasma thromboplastin antecedent, antihemophilic factor C), Factor XII (Hageman factor, surface factor, contact factor), and Factor XIII (fibrin stabilizing factor, fibrin stabilizing enzyme, fibri-nase).
In some embodiments, the present invention provides the delivery of anti-inflammatory agents, including, but not limited to, non steroidal anti-inflammatory drugs (NSAIDs) including diclofenac (also known as Voltaren, Abitren, Allvoran, Almiral, Alonpin, Anfenax, Artrites, Betaren, Blesin, Bolabomin, Cataflam, Clofec, Clofen, Cordralan, Curinflam, Diclomax, Diclosian, Dicsnal, Difenac, Ecofenac, Hizemin, Inflamac, Inflanac, Klotaren, Lidonin, Monoflam, Naboal, Oritaren, Remethan, Savismin, Silino, Staren, Tsudohmin, Voltarol, Voren, Voveran, and Vurdon), diflunisal (also known as Dolobid, Adomal, Diflonid, Diflunil, Dolisal, Dolobis, Dolocid, Donobid, Dopanone, Dorbid, Dugodol, Flovacil, Fluniget, Fluodonil, Flustar, Ilacen, Noaldol, Reuflos, and Unisal), etodolac (also known as Lodine), fenoprofen (also known as Nalfon, Fenoprex, Fenopron, Fepron, Nalgesic, and Progesic), flurbiprofen (also known as Ansaid and Ocuflur), ibuprofen (also known as Rufen, Motrin, Aches-N-Pain, Advil, Nuprin, Dolgesic, Genpril, Haltran, Ibifon, Ibren, Ibumed, Ibuprin, Ibupro-600, Ibuprohm, Ibu-Tab, Ibutex, Ifen, Medipren, Midol 200, Motrin-IB, Cramp End, Profen, Ro-Profen, Trendar, Alaxan, Brofen, Alfam, Brufen, Algofen, Brufort, Amersol, Bruzon, Andran, Buburone, Anflagen, Butacortelone, Apsifen, Deflem, Artofen, Dolgit, Artril, Dolocyl, Bloom, Donjust, Bluton, Easifon, Ebufac, Emflam, Emodin, Fenbid, Fenspan, Focus, Ibosure, Ibufen, Ibufug, Ibugen, Ibumetin, Ibupirac, Imbun, Inabrin, Inflam, Irfen, Librofen, Limidon, Lopane, Mynosedin, Napacetin, Nobafon, Nobgen, Novogent, Novoprofen, Nurofen, Optifen, Paduden, Paxofen, Perofen, Proartinal, Prontalgin, Q-Profen, Relcofen, Remofen, Roidenin, Seclodin, Tarein, and Zofen), indomethacin (also known as Indameth, Indocin, Amuno, Antalgin, Areumatin, Argilex, Artherexin, Arthrexin, Artrinovo, Bavilon, Bonidon, Boutycin, Chrono-Indocid, Cidalgon, Confortid, Confortind, Domecid, Durametacin, Elemetacin, Idicin, Imbrilon, Inacid, Indacin, Indecin, Indocap, Indocen, Indocid, Indoflex, Indolag, Indolar, Indomed, Indomee, Indometacinum, Indometicina, Indometin, Indovis, Indox, Indozu, Indrenin, Indylon, Inflazon, Inpan, Lauzit, Liometace, Metacen, Metindon, Metocid, Mezolin, Mobilan, Novomethacin, Peralgon, Reflox, Rheumacid, Rheumacin, Salinac, Servindomet, Toshisan, and Vonum), ketoprofen (also known as Orudis, Alrheumat, Alrheumun, Alrhumat, Aneol, Arcental, Dexal, Epatec, Fastum, Keduril, Kefenid, Keprofen, Ketofen, Ketonal, Ketosolan, Kevadon, Mero, Naxal, Oruvail, Profenid, Salient, Tofen, and Treosin), ketorolac (also known as Toradol), meclofenamate (also known as Meclofen, Meclomen, and Movens), mefenamic acid (also known as Ponstel, Alpain, Aprostal, Benostan, Bonabol, Coslan, Dysman, Dyspen, Ecopan, Lysalgo, Manic, Mefac, Mefic, Mefix, Parkemed, Pondex, Ponsfen, Ponstan, Ponstyl, Pontal, Ralgec, and Youfenam), nabumetone (also known as Relafen), naproxen (also known as Naprosyn, Anaprox, Aleve, Apranax, Apronax, Arthrisil, Artrixen, Artroxen, Bonyl, Congex, Danaprox, Diocodal, Dysmenalgit, Femex, Flanax, Flexipen, Floginax, Gibixen, Headlon, Laraflex, Laser, Leniartil, Nafasol, Naixan, Nalyxan, Napoton, Napren, Naprelan, Naprium, Naprius, Naprontag, Naprux, Napxen, Narma, Naxen, Naxid, Novonaprox, Nycopren, Patxen, Prexan, Prodexin, Rahsen, Roxen, Saritilron, Sinartrin, Sinton, Sutony, Synflex, Tohexen, Veradol, Vinsen, and Xenar), oxaprozin (also known as Daypro), piroxicam (also known as Feldene, Algidol, Antiflog, Arpyrox, Atidem, Bestocam, Butacinon, Desinflam, Dixonal, Doblexan, Dolonex, Feline, Felrox, Fuldin, Indene, Infeld, Inflamene, Lampoflex, Larapam, Medoptil, Novopirocam, Osteral, Pilox, Piraldene, Piram, Pirax, Piricam, Pirocam, Pirocaps, Piroxan, Piroxedol, Piroxim, Piton, Posidene, Pyroxy, Reucam, Rexicam, Riacen, Rosic, Sinalgico, Sotilen, Stopen, and Zunden), sulindac (also known as Clinoril, Aflodac, Algocetil, Antribid, Arthridex, Arthrocine, Biflace, Citireuma, Clisundac, Imbaral, Lindak, Lyndak, Mobilin, Reumofil, Sudac, Sulene, Sulic, Sulindal, Suloril, and Sulreuma), tolmetin (also known as Tolectin, Donison, Midocil, Reutol, and Safitex), celecoxib (also known as Celebrex), meloxicam (also known as Mobic), rofecoxib (also known as Vioxx), valdecoxib (also known as Bextra), aspirin (also known as Anacin, Ascriptin, Bayer, Bufferin, Ecotrin, and Excedrin) and steroidal anti-inflammatory drugs including cortisone, prednisone and dexamethasone.
In some embodiments, the present invention provides the delivery of vasoconstrictors, including, but not limited to, epinephrine (adrenaline, Susphrine), phenylephrine hydrochloride (Neo-Synephrine), oxymetazoline hydrochloride (Afrin), norepinephrine (Levophed), and caffeine.
In some embodiments, the present invention provides the delivery of vasodilators, including, but not limited to, bosentan (Tracleer), epoprostenol (Flolan), treprostinil (Remodulin), sitaxsentan, nifedipine (Adalat, Procardia), nicardipine (Cardene), verapamil (Calan, Covera-HS, Isoptin, Verelan), diltiazem (Dilacor XR, Diltia XT, Tiamate, Tiazac, Cardizem), isradipine (DynaCirc), nimodipine (Nimotop), amlodipine (Norvasc), felodipine (Plendil), nisoldipine (Sular), bepridil (Vascor), hydralazine (Apresoline), minoxidil (Loniten), isosorbide dinitrate (Dilatrate-SR, Iso-Bid, Isonate, Isorbid, Isordil, Isotrate, Sorbitrate), isorbide mononitrate (IMDUR), prazosin (Minipress), cilostazol (Pletal), treprostinil (Remodulin), cyclandelate, isoxsuprine (Vasodilan), nylidrin (Arlidin), nitrates (Deponit, Minitran, Nitro-Bid, Nitrodisc, Nitro-Dur, Nitrol, Transderm-Nitro), benazepril (Lotensin), benazepril and hydrochlorothiazide (Lotensin HCT), captopril (Capoten), captopril and hydrochlorothiazide (Capozide), enalapril (Vasotec), enalapril and hydrochlorothiazide (Vaseretic), fosinopril (Monopril), lisinopril (Prinivil, Zestril), lisinopril and hydrochlorothiazide (Prinzide, Zestoretic), moexipril (Univasc), moexipril and hydrochlorothiazide (Uniretic), perindopril (Aceon), quinapril (Accupril), quinapril and hydrochlorothiazide (Accuretic), ramipril (Altace), trandolapril (Mavik), papaverine (Cerespan, Genabid, Pavabid, Pavabid HP, Pavacels, Pavacot, Pavagen, Pavarine, Pavased, Pavatine, Pavatym, Paverolan).
In some embodiments, the present invention provides the delivery of diuretics, including, but not limited to, acetazolamide (Diamox), dichlorphenamide (Daranide), methazolamide (Neptazane), bendroflumethiazide (Naturetin), benzthiazide (Exna), chlorothiazide (Diuril), chlorthalidone (Hygroton), hydrochlorothiazide (Esidrix, HydroDiuril, Microzide), hydroflumethiazide (Diucardin), indapamide (Lozol), methyclothiazide (Enduron), metolazone (Zaroxolyn, Mykrox), polythiazide (Renese), quinethazone (Hydromox), trichlormethiazide (Naqua), bumetanide (Bumex), ethacrynic acid (Edecrin), furosemide (Lasix), torsemide (Demadex), amiloride (Midamor), amiloride and hydrochlorothiazide (Moduretic), spironolactone (Aldactone), spironolactone and hydrochlorothiazide (Aldactazide), triamterene (Dyrenium), triamterene and hydrochlorothiazide (Dyazide, Maxzide).
In some embodiments, the present invention provides the delivery of anti-cancer agents, including, but not limited to, aldesleukin, alemtuzumab, alitretinoin, allopurinol, altretamine, amifostine, anagrelide, anastrozole, arsenic trioxide, asparaginase, bexarotene, bicalutamide, bleomycin, busulfan, calusterone, capecitabine, carboplatin, carmustine, celecoxib, chlorambucil, cisplatin, cladribine, cyclophosphamide, cytarabine, dacarbazine, dactinomycin, darbepoetin alpha, daunorubicin, daunomycin, dexrazoxane, docetaxel, doxorubicin, epoetin alpha, estramustine, etoposide, etoposide phosphate, exemestane, filgrastim, floxuridine, fludarabine, flutamide, fulvestrant, gemcitabine, gemtuzumab ozogamicin, goserelin acetate, hydroxyurea, ibritumomab tiuxetan, idarubicin, ifosfamide, imatinib mesylate, interferon alpha-2a, interferon alpha-2b, irinotecan, leflunomide, letrozole, leucovorin, levamisole, lomustine, meclorethamine (nitrogen mustard), megestrol acetate, melphalan, mercaptopurine, mesna, methotrexate, methoxsalen, mitomycin C, mitotane, mitoxantrone, mycophenolate mofetil, nandrolone phenpropionate, nilutamide, nofetumomab, oprelvekin, oxaliplatin, paclitaxel, pamidronate, pegademase, pegaspargase, pegfilgrastim, pentostatin, pipobroman, plicamycin, porfimer sodium, procarbazine, quinacrine, rasburicase rituximab, sargramostim, streptozocin, tacrolimus, tamoxifen, temozolomide, teniposide, testolactone, thioguanine, thiotepa, topotecan, toremifene, tositumomab, trastuzumab, tretinoin, uracil mustard, valrubicin, vinblastine, vincristine, vinorelbine, and zoledronate.
In other embodiments, the wound active agent is an siRNA. The RNAi constructs of the present invention are gene(s) that express RNAs that base pair to form a dsRNA RNA region. The RNAs may be a part of the same molecule or different molecules. In preferred embodiments, the RNAi construct comprises a promoter operably linked to a nucleic acid sequence encoding two complementary sequences separated by a loop sequence. The complementary regions correspond to a target RNA sequence separated by a loop sequence. When the RNAi construct is expressed, the complementary regions of the resulting RNA molecule pair with one another to form a double stranded RNA region. The present invention is not limited to loop sequences of any particular length. In some preferred embodiments, the loop sequences range from about 4 to about 20 nucleotides in length. In more preferred embodiments, the loop sequences are from about 6 to about 12 nucleotides in length. In other preferred embodiments, the dsRNA regions are from about 19 to about 23 in length.
In other embodiments, the dsRNA is formed from RNA transcribed from a vector as two separate stands. In other embodiments, the two strands of DNA used to form the dsRNA may belong to the same or two different duplexes in which they each form with a DNA strand of at least partially complementary sequence. When the dsRNA is thus-produced, the DNA sequence to be transcribed is flanked by two promoters, one controlling the transcription of one of the strands, and the other that of the complementary strand. These two promoters may be identical or different. In some embodiments, a DNA duplex provided at each end with a promoter sequence can directly generate RNAs of defined length, and which can join in pairs to form a dsRNA. See, e.g., U.S. Pat. No. 5,795,715, incorporated herein by reference. RNA duplex formation may be initiated either inside or outside the cell.
It will be recognized that after processing the resulting siRNA can comprise two blunt ends, one blunt end and one end with an overhang, or two ends with overhangs. In some embodiments, the end or ends with overhangs comprise an overhang of either one or two nucleotides. As a non-limiting example, a siRNA of 23 nucleotides in length comprises two 19mers with a two nucleotide overhang at each end. As another non-limiting example, a siRNA of 21 nucleotides in length comprises two 19mers with a single nucleotide overhang at each end. As still another non-limiting example, a siRNA of 22 nucleotides in length comprises two 22mers with no overhangs at either end.
Inhibition is sequence-specific in that nucleotide sequences corresponding to the duplex region of the RNA are targeted for genetic inhibition. RNA molecules containing a nucleotide sequence identical to a portion of the target gene are preferred for inhibition. RNA sequences with insertions, deletions, and single point mutations relative to the target sequence have also been found to be effective for inhibition. Thus, sequence identity may optimized by sequence comparison and alignment algorithms known in the art (see Gribskov and Devereux, Sequence Analysis Primer, Stockton Press, 1991, and references cited therein) and calculating the percent difference between the nucleotide sequences by, for example, the Smith-Waterman algorithm as implemented in the BESTFIT software program using default parameters (e.g., University of Wisconsin Genetic Computing Group). Greater than 90% sequence identity, or even 100% sequence identity, between the inhibitory RNA and the portion of the target gene is preferred. Alternatively, the duplex region of the RNA may be defined functionally as a nucleotide sequence that is capable of hybridizing with a portion of the target gene transcript.
There is no upper limit on the length of the dsRNA that can be used. For example, the dsRNA can range from about 21 base pairs (bp) of the gene to the full length of the gene or more. In one embodiment, the dsRNA used in the methods of the present invention is about 1000 bp in length. In another embodiment, the dsRNA is about 500 bp in length. In yet another embodiment, the dsRNA is about 22 bp in length. In some preferred embodiments, the sequences that mediate RNAi are from about 21 to about 23 nucleotides. The isolated iRNAs of the present invention mediate degradation of the target RNA.
The double stranded RNA of the present invention need only be sufficiently similar to natural RNA that it has the ability to mediate RNAi for the target RNA. In one embodiment, the present invention relates to RNA molecules of varying lengths that direct cleavage of specific mRNA to which their sequence corresponds. It is not necessary that there be perfect correspondence of the sequences, but the correspondence must be sufficient to enable the RNA to direct RNAi cleavage of the target mRNA. In a particular embodiment, the RNA molecules of the present invention comprise a 3′ hydroxyl group.

III. Matrix Compositions

In some embodiments, the present invention provides compositions comprising a matrix that can be applied to a wound. In some embodiments, the matrix is functionalized. In some embodiments, the matrix comprises one or more polymers, preferably biocompatible, or is formed from one more proteins, or is a combination of polymers and proteins. The matrix is preferably functionalized to allow for covalent interaction and/or binding to the wound bed, or to allow application of wound active agents to the matrix. In some embodiments, a wound active agent, for example an antimicrobial agent such as a solver compound, is incorporated into the matrix. In some embodiments, the matrix is formed or provided on a solid support. The solid support can form an outer permeable, semi-permeable, or impermeable barrier after application of the matrix to a wound or can serve as a removed support for transfer and application of the matrix to the wound followed by removal of the support. The present invention is not limited to any particular solid support. Indeed, a variety of solid supports are contemplated, including, but not limited to, solid supports formed from elastomeric materials such PDMS, nylon, Teflon®, Gortex®, silk, polyurethane, silicon, preferably medical grade silicon, PVDF, and solids supports formed from polyvinyl alcohol and polyethylene oxide. In some embodiments, the solid support is a wound dressing that is compatible with functionalization by addition of a matrix material. Examples of commercially available wound dressings that can be modified by addition of a matrix as described below include, but are not limited to, Biobrane™, gauze, adhesive tape, bandages such as Band-Aids®, and other commercially available wound dressings including but not limited to COMPEEL®, DUODERM™, TAGADERM™ and OPSITE®.
In some embodiments, the matrices, such as polymer multilayers, are nanoscale to microscale in dimension. Accordingly, in some embodiments, the matrices are from about 1 nm to 1000 nm thick, from about 1 nm to 500 nm thick, from about 1 nm to 100 nm thick, from about 1 nm to about 25 nm thick, from about 1 nm to about 10 nm thick, or less than about 500 nm, 100 nm, 25 nm or 10 nm thick. It is contemplated that the nanoscale dimension of the matrices (i.e., the nanoscale thickness) allows for the loading of a lower total amount of an active agent while still allowing delivery of an effective amount (i.e., an amount of active agent that accelerates wound healing as compared to controls) of the active agent as compared to matrix structures with greater thickness. It is contemplated that the lower total loading levels result in reduced toxicity in the wound environment, especially when antimicrobial compounds are incorporated into the polymer multilayer.
In some embodiments, the compliance of the matrices, such as polymer multilayers, is adjusted to facilitate cell migration in the wound. In some embodiments, the matrices have a compliance, measured in kilopascals (kPa) of from about 3 to about 500 kPa, about 7 to about 250 kPa, about 10 to about 250 kPA or from about 10 to about 200 kPa. In some embodiments, the matrices, e.g., polymer multilayers, have a compliance of from about 3 kPa to 5, 4, 3, 2, 1, 0.5, 0.1 and 0.05 GPa (gigapascals).
A. Polymer Matrix Materials
In some embodiments, the matrix is a polymer multilayer. In some embodiments, the multilayer structures comprise layers of polyelectrolytes (i.e., forming a polyelectrolyte multilayer), while in other embodiments, the multilayers comprise polymers that do not have a charge (i.e., non-ionic polymers) or a combination of charged and uncharged polymer layers. In some embodiments, it is contemplated that polyelectrolyte films built-up by the alternated adsorption of cationic and anionic polyelectrolyte layers constitute a novel and promising technique to modify wound surfaces in a controlled way [(Decher et al., 1992, Thin Solid Films 210/211:831; Decher, 1997, Science 277:1232). One of the most important properties of such multilayers is that they exhibit an excess of alternatively positive and negative charges (Caruso et al., 1999, J Am Chem Soc 121:6039; Ladam et al., 2000, Langmuir 16:1249). Not only can this constitute the motor of their buildup (Joanny, 1999, Eur. Phys. J. Biol. 9:117), but it allows, by simple contact, to adsorb a great variety of compounds such as dyes, particles (Cassagneau et al., 1998, J. Am. Chem. Soc. 120:7848; Caruso et al., 1999, Langmuir 15:8276; Lvov et al., 1997, Langmuir 13:6195), clay microplates (Ariga et al., 1999, Appl. Clay Sci. 15:137) and proteins (Keller et al., 1994, J. Am. Chem. Soc. 116:8817; Lvov et al., 1995, J. Am. Chem. Soc. 117:6117; Caruso et al., 1997, Langmuir 13:3427).
Polyelectrolyte layers are formed by alternating applications of anionic polyelectrolytes and cationic polyelectrolytes to surfaces to form a polyelectrolyte multilayer. In some embodiments, one or more wound active agents, such as those described above, are incorporated into the multilayer. Preferably, at least four layers, and, more preferably, at least six layers are used to form the polyelectrolyte multilayer.
Cationic polyelectrolytes useful in the present invention can be any biocompatible water-soluble polycationic polymer, for example, any polymer having protonated heterocycles attached as pendant groups. As used herein, “water soluble” means that the entire polymer must be soluble in aqueous solutions, such as buffered saline or buffered saline with small amounts of added organic solvents as co-solvents, at a temperature between 20 and 37° Centigrade. In some embodiments, the material will not be sufficiently soluble (defined herein as soluble to the extent of at least one gram per liter) in aqueous solutions per se but can be brought into solution by grafting the polycationic polymer with water-soluble polynonionic materials such as polyethylene glycol.
Representative cationic polyelectrolytes include natural and unnatural polyamino acids having net positive charge at neutral pH, positively charged polysaccharides, and positively charged synthetic polymers. Examples of suitable polycationic materials include polyamines having amine groups on either the polymer backbone or the polymer side chains, such as poly-L-lysine (PLL) and other positively charged polyamino acids of natural or synthetic amino acids or mixtures of amino acids, including, but not limited to, poly(D-lysine), poly(ornithine), poly(arginine), and poly(histidine), and nonpeptide polyamines such as poly(aminostyrene), poly(aminoacrylate), poly (N-methyl aminoacrylate), poly (N-ethylaminoacrylate), poly(N,N-dimethyl aminoacrylate), poly(N,N-diethylaminoacrylate), poly(aminomethacrylate), poly(N-methyl amino-methacrylate), poly(N-ethyl aminomethacrylate), poly(N,N-dimethyl aminomethacrylate), poly(N,N-diethyl aminomethacrylate), poly(ethyleneimine), polymers of quaternary amines, such as poly(N,N,N-trimethylaminoacrylate chloride), poly(methyacrylamidopropyltrimethyl ammonium chloride), and natural or synthetic polysaccharides such as chitosan.
In general, the polymers must include at least five charges, and the molecular weight of the polycationic material must be sufficient to yield the desired degree of binding to a tissue or other surface, having a molecular weight of at least 1000 g/mole.
Polyanionic materials useful in the present invention can be any biocompatible water-soluble polyanionic polymer, for example, any polymer having carboxylic acid groups attached as pendant groups. Suitable materials include alginate, carrageenan, furcellaran, pectin, xanthan, hyaluronic acid, heparin, heparan sulfate, chondroitin sulfate, dermatan sulfate, dextran sulfate, poly(meth)acrylic acid, oxidized cellulose, carboxymethyl cellulose and crosmarmelose, synthetic polymers and copolymers containing pendant carboxyl groups, such as those containing maleic acid or fumaric acid in the backbone. Polyaminoacids of predominantly negative charge are also suitable. Examples of these materials include polyaspartic acid, polyglutamic acid, and copolymers thereof with other natural and unnatural amino acids. Polyphenolic materials such as tannins and lignins can be used if they are sufficiently biocompatible. Preferred materials include alginate, pectin, carboxymethyl cellulose, heparin and hyaluronic acid.
In some embodiments, the cationic polyelectrolyte used is PLL and the anionic polyelectrolyte used is poly(L-glutamic acid) (PGA). Indeed, the use of a variety of polyelectrolytes is contemplated, including, but not limited to, poly(ethylene imine) (PEI), poly(allylamine hydrochloride) (PAH), poly(sodium 4-styrenesulfonate) (PSS), poly(acrylic acid) (PAC), poly(maleic acid-co-propylene) (PMA-P), and poly(vinyl sulfate) (PVS). It is also possible to use naturally occurring polyelectrolytes, including hyaluronic acid and chondroitin sulfate. In still further embodiments, the polymer is a dendrimer, grafted polymer, or star architecture polymer.
In some embodiments, the multilayer structures are formed from uncharged polymers or from a combination of charged and uncharged polymers. Examples of uncharged polymers include, but are not limited to, dextran, dextran sulfate, diethylaminoethyl (DEAE)-dextran, hydroxyethyl cellulose, ethyl(hydroxyethyl) cellulose, acrylamide, polyethylene oxide, polypropylene oxide, polyethylene oxide-polypropylene oxide copolymers, PAAN_a, Ficoll, polyvinylpyrolidine, and polyacrylic acid.
In some embodiments, the multilayer structures are formed from one or more amphoteric polymers, alone in combination with the other polymers described herein. In some embodiments, the amphoteric polymers comprise one or more of acrylic acid (AA), DMAEMA (dimethylaminoethyl methacrylate), APA (2-aminopropyl acrylate), MorphEMA (morpholinoethyl methacrylate), DEAEMA (diethylaminoethyl methacrylate), t-ButylAEMA (t-butylaminoethyl methacrylate), PipEMA (piperidinoethyl methacrylate), AEMA (aminoethyl methacrylate), HEMA (2-hydroxyethyl methacrylate), MA (methyl acrylate), MAA (methacrylic acid) APMA (2-aminopropyl methacrylate), AEA (aminoethyl acrylate). In some embodiments, the amphoteric polymer comprises (a) carboxylic acid, (b) primary amine, and (c) secondary and/or tertiary amine. The amphoteric polymers have an isoelectric point of 4 to 8, preferably 5 to 7 and have a number average molecular weight in the range of 10,000 to 150,000.
Polymer layers may be formed by a variety of methods. In some embodiments, the polymer layers are formed on solid supports as described in detail below. In some embodiments, it is contemplated that the polymer or polymer multilayers is formed by sequential application of polymers using either a pump (including syringes, ink jet printers, and electrojets) or spray, such as an aerosol spray. In other embodiments, particle bombardment is utilized. In other embodiments, the use of a brush including an air brush is contemplated. In other embodiments, a sponge is utilized. In other embodiments a solid support or stamp such as an elastomeric material, for example, PDMS (polydimethylsiloxane), silicone, hydrogel or latex, is used to support the polymer layer and mechanically transfer the polymer layer into or onto the wound bed.
In some embodiments, the matrix comprises one or more proteins. In preferred embodiments, the proteins form a hydrogel. In some preferred embodiments, the matrix comprises one or more extracellular matrix proteins. In some embodiments, the matrix comprises at least one of collagen, laminin, vitronectin, fibronectin, keratin, and combinations thereof. As described above, the protein matrix may preferably be formed by a variety of methods. In some embodiments, the protein matrix is formed on solid supports as described in detail below. In some embodiments, it is contemplated that the protein matrix is formed by application of proteins or solutions or gels of proteins using either a pump (including syringes, ink jet printers, and electrojets) or spray, such as an aerosol spray. In other embodiments, the use of a brush including an air brush is contemplated. In other embodiments, a sponge is utilized. In other embodiments a solid support or stamp such as an elastomeric material, for example, PDMS (polydimethylsiloxane), silicone, hydrogel or latex, is used to support the protein matrix and mechanically transfer the protein matrix into or onto the wound bed.
In some embodiments, the matrix is further modified to include cells, including, but not limited to, stem cells, keratinocytes, 3-D skin constructs, corneal epithelial cells, conjunctival cells, corneal limbal stem cell, human embryonic stem cells, pluripotential stem cells, adult induced stem cells, hematopoietic stem cells, hepatocytes, pancreatic cells and the like. In some embodiments, the compositions and methods described herein are used to functionalize harvested and processed (frozen, freeze dried, fixed and stored dry or wet, fresh tissue for direct transplant) animal and human tissue (pig/human aortic valve, harvested human amniotic membrane, human cadaver skin, harvested sclera and cornea, harvested cadaver bone, harvested blood vessels and the like. In some embodiments, the compositions and methods described herein are used to functionalize skin constructs, including, but not limited to, autograft skin (i e, skin is harvested from a patient, functionalized as described herein, and returned to the patient), organotypically cultured human skin equivalents, and other keratinocyte products such as Dermagraft™.
B. Polymer Multilayers Associated with Microscale or Nanoscale Beads
In some embodiments, the present invention provides polymer multilayers that comprise nano- or microscale particles. In some embodiments, the particles are dispersed in the polymer multilayer, for example, in between the polymer layers. In other embodiments, the particles are displayed on a surface, such as a top or a bottom surface, of the polymer multilayer. In some embodiments, the particles are associated with said polymer multilayer in a manner selected from the group consisting of interspersed or dispersed in said polymer multilayer; displayed on a surface of said polymer multilayer; and underneath the polymer multilayer.
In some embodiments, the polymer multilayers are formed as described above. In some preferred embodiments, the particles have diameter or other linear measurement of a feature, such as a length or width, which is greater than the thickness of polymer multilayer. In some embodiments, the diameter or other linear measurement is from about 1, 1.5, 2, 3, or 4 times greater than the thickness of the polymer multilayer up to about 5, 10 or 20 times greater than thickness of the polymer multilayer.
In some embodiments, nanometer to micrometer sized biocompatible particles, such as spherical (e.g., beads) and/or non-spherical (e.g., oblongs, needles, cubes, tetrahedral, mushroom-like structures, haybale-like structures) particles or electrospun polymers, are utilized in or on the polymer multilayer. Microbeads have a size generally ranging from about 1 to about 500 micrometers, while nanobeads have a size generally ranging from about 1 to about 1000 nanometers. Microbeads may further comprise micro- (i.e., from 1 to 100 micrometers) or nano-scale (0.1 to 1000 nanometer) features on the surface of the bead. Nanobeads may further comprise nanoscale features (i.e., 0.1 to 500 nanometer features) on the surface of the bead. In some embodiments, a wound active agent is present in the form of a bead or particle, such as silver nanoparticles. In some embodiments, the biocompatible particles are biodegradable. In some embodiments, the biocompatible particles, for example, are modified with surface chemistry cross-linkers that allow attachment and immobilization of wound active agents, extracellular matrix compounds, etc. as described elsewhere herein. In some embodiments, the size of the biocompatible particles, such as beads, are at least 1 nm, at least 5 nm, at least 10 nm, at least 20 nm, at least 50 nm, at least 100 nm, at least 200 nm, at least 300 nm, at least 500 nm, or at least 800 nm in diameter. In some embodiments, beads and other spherical and non-spherical particles contain their own surface topography. For example, the bead surface may comprise undulations, indentations, tunnels, holes, knobs, ridges, etc. Spherical particles, such as beads, may or may not be inert and may, for example, be magnetic. Magnetic beads comprise, for example, a magnetic core or magnetic particles. Examples of different bead compositions are found at, for example, U.S. Pat. Nos. 5,268,178, 6,458,858, 6,869,858, and 5,834,121, each of which is incorporated herein by reference in its entirety. In some embodiments, the particles comprise or are impregnated with a wound active agent.
It is contemplated that polymer multilayers such as those described above offer the opportunity to chemically and topographically engineer the surface of substrates. Using existing technologies, one has to construct nanostructures or organic films (like polymer-multilayers) onto those surfaces, and dope them with active agents. Since these procedures are laborious (it can take 6 hrs to fabricate a multilayer films containing 20 layers, which is prohibitively long for say treatment of a wound), can involve harsh chemicals, solutions having non-physiological pHs, and possible mechanical shear forces, they may damage or compromise the substrates on which they are formed (particularly biological tissues and sensitive biomedical devices). To overcome these limitations, in some embodiments, the polymer multilayers of the present invention are pre-fabricated on elastomeric stamps (such as PDMS stamps) and then mechanically transferred to a substrate of interest by stamping onto the substrates of interest. Although the concept of contact printing pre-fabricated nano and microstructures on hard substrates (microscope slides, silicon wafers) has been employed for microfabrication of electromechanical systems; those methods fail when used on soft substrates, particularly substrates with mechanical properties typically of a range of biological tissues.
The present invention provides methods and compositions of matter that make possible the transfer of organic and inorganic thin films, including polymer multilayers, onto compliant substrates, including soft-substrates with mechanical properties equivalent to those of biological tissues (elastic modulus, E′, of about 1-500 kPa, preferably about 10-100 kPa). Existing methods described in literature which allow transfer of organic thin films onto rigid substrates like glass (E′˜65 GPa) with various surface chemistries, fail when used on soft-surfaces (E′˜100 kPa). FIG. 11 demonstrates these observations. The method demonstrated in Example 14 and FIG. 12 facilitates transfer of polymer-multilayers onto soft-surfaces, including biological tissues, including skin-grafts and mouse pelts. Incorporation of polymer-microspheres (E′˜3 GPa) within an assembly of polymer-multilayers on an elastomeric stamp, when stamped onto a human skin-graft or a biomedical grade soft silicone elastomer (E′˜100 kPa), leads to a substantially complete transfer of rigid-microspheres and polymer-multilayers in contact with the microspheres.
This method allows engineering the surface of soft-substrates (E′˜100 kPa) by contact printing pre-fabricated functionalized polymer-multilayers onto their surface. This opens up a vast area of opportunities to chemically and topographically modify surfaces of biological tissues and soft implantable biomedical devices, like biomedical grade silicone, and generate surfaces with tailored functionality, chemistry and topography at nanometer scale. This is a versatile solution to engineer or pattern, for example, a wound-bed, from two perspectives. First, from a product development view-point, fabrication and functionalization of polymer multilayers used in this approach can be easily automated in a manufacturing environment using robots. Second, from application view-point, an end-user would simply have to contact-print materials from the stamps onto the substrates, instead of preparing multilayers on the substrates.
Accordingly, the present invention provides methods to tailor the surface chemistry and nanostructured topography of soft-substrates by mechanical transfer of pre-fabricated, nanometer-thick organic films, impregnated with active agents, onto the substrates. This technology provides unprecedented advantages over several competing existing technologies. First, technology described in past literature for stamping pre-fabricated polymer-multilayer films onto substrates relevant for the microfabrication of electromechanical systems does not allow their transfer onto soft-substrates with mechanical strength relevant to biological tissues. Thus, the present invention opens up the possibilities of engineering surfaces of a whole new vast arena of soft substrates by contact-printing pre-fabricated functionalized polymer-films. Some of such soft-substrates relevant for immediate commercialization of this technology include biological tissues, wound-beds, and implantable biomedical devices like biomedical grade silicone. Furthermore, the study performed during this invention leads to the new observation that mechanical properties of the substrates influence the mechanical transfer of organic films onto them—these new principles of mechanical transfer can be used to selective transfer organic films on substrates with, for example, patterned soft and hard regions.
Second, to chemically or topographically modify the surface of soft-substrates (E′˜100 kPa) using existing technologies, one has to construct nanostructures or organic films (like polymer-multilayers) onto those surfaces, and dope them with active agents. Since these procedures mostly involve harsh chemicals, solutions at non-physiological pHs, and possible mechanical shear forces, they may disrupt the sensitive-substrates, particularly biological tissues and sensitive biomedical devices. The invention described here allows to contact-print pre-fabricated polymer-multilayers impregnated with active agents onto the soft-substrates, instead of assembling them on those substrates. Furthermore, the direct stamping of pre-fabricated polymer-multilayers onto the substrates provide precise control over the two and three-dimensional placement of the polymer-multilayers. By sequential stamping of multiple, pre-fabricated polymer-multilayers using the methodology, multilevel and multi-component pattern structures can be conveniently introduced onto device surfaces. Thus, this invention provides unprecedented control at nanometers-level over the surface-modification of soft-substrates.
Third, in the context of wound-healing, current clinical wound-management approaches involve delivering active agents to the wounds in ointments or dressings. The wound-dressings are reservoirs of active agents and require high loading concentrations for the active agents to diffuse through the wound-fluid and reach the wound-bed where activity is required. High concentrations of active agents are cytotoxic, causing tissue toxicity and impaired wound-healing.
The present invention allows immobilizing active agents onto the surface of the wound-beds by stamping pre-fabricated nanostructured polymer-multilayers impregnated with active agents. Such immobilization of active agents in polymer-multilayers over wound-bed permits: 1) Precise delivery and minimal loading of active molecules onto the wound-bed, thereby providing efficacious wound treatment without cytotoxic effects and at reduced costs. 2) Prolong bioavailability of the active agents in the wound-bed, circumventing frequent dressings and thus reducing patient pain and overall costs of wound-management. This is particularly significant in the treatment of chronic wounds that take several months to heal. 3) Controlled delivery of bioactive molecules, both spatially and temporally. This allows regulating the distribution of active molecules across the wound-bed and creating their gradients. For example, in vitro studies have shown that gradients of growth-factors promote the migration of cells involved in wound-healing to the wound-bed and can expedite wound-closure. 4) Putting active molecules directly into the cellular microenvironment, increasing their local concentration and avoiding problems of mass transfer limitations or complex aggregation encountered in release systems. 5) Maintaining the active molecules locally in the matrix, limiting any systemic loss or potential undesirable diffusion to distant sites.
This approach to wound-healing using current invention is fundamentally new in the sense that it attempts to ‘engineer the wound-bed’. The wound-bed surface is modified chemically and topographically using nanometer-thick organic films impregnated with minimal concentrations of active agents. This contrasts to currently practiced approaches which attempt to treat the wound by drizzling high concentrations of bioactive agents over the wound.
Accordingly, in some embodiments, the present invention provides a polymer multilayer comprising at least one polymer, the polymer multilayer having associated therewith particles selected from the group consisting of nanoscale and microscale particles. In some embodiments, the polymer multilayer is from 1 nm to 1000 nm thick and in preferred embodiments, from about 1 to about 250 nm thick. In some embodiments, the polymer multilayer has a compliance of from 3 to 500 kPa. In some embodiments, the polymer multilayer is disposed on a support. In some embodiments, the polymer multilayer is formed on a support. In some preferred embodiments, the support is an elastomeric support.
In some embodiments, the present invention provides methods for modifying a surface comprising contacting a surface with a polymer multilayer as described above under conditions such that said polymer multilayer is transferred to said surface. In some embodiments, the surface is a soft surface. In some embodiments, the surface has an elastic modulus of from about 1 to about 500 kPa, preferably about 10 to about 100 kPa. In some embodiments, the surface is a biological surface. In some embodiments, the biological surface comprises proteins, lipids and/or carbohydrates. In some embodiments, the biological surface is selected from the group consisting of skin, a wound bed, hair, a tissue surface, and an organ surface. In some embodiments, the surface is a biologically compatible surface, or the surface of a biomedical device. In some embodiments, the surface is a silicone surface.
C. Functionalization Agents
In some embodiments, the matrices described above are functionalized. In preferred embodiments, the matrices are functionalized with one or more covalent modification agents. In some preferred embodiments, the crosslinkers comprise either an azide group or an alkyne group so that suitable click chemistries can be utilized. In some embodiments, the at least one covalent modification agent is a homobifunctional cross-linker. In other embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker. For example, in some embodiments, the homobifunctional cross-linker is an N-hydroxysuccinimidyl ester (e.g., including, but not limited to, disuccinimidyl ester, dithiobis(succinimidylpropionate), 3,3′-dithiobis(sulfosuccinimidylpropionate), disuccinimidyl suberate, bis(sulfosuccinimidyl)suberate, disuccinimidyl tartarate, disulfosuccinimidyl tartarate, bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone, bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl]sulfone, ethylene glycolbis(succinimidylsuccinate), ethylene glycolbis(sulfosuccinimidylsuccinate), disuccinimidyl glutarate, and N,N′-disuccinimidylcarbonate). In some embodiments, the homobifunctional cross-linker is at a concentration between 1 nanomolar and 10 millimolar. In some preferred embodiments, the homobifunctional cross-linker is at a concentration between 10 micromolar and 1 millimolar. In other embodiments, the at least one covalent modification agent is a heterobifunctional cross-linker (e.g., including, but not limited to, N-succinimidyl 3-(2-pyridyldithio)propionate, succinimidyl 6-(3-[2-pyridyldithio]-propionamido)hexanoate, sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido)hexanoate, succinimidyloxycarbonyl-α-methyl-α-(2-pyridyldithio)toluene, sulfosuccinimidyl-6-[α-methyl-α-(2-pyridyldithio)toluamido]hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, m-maleimidobenzoyl-N-hydroxysuccinimide ester, m-maleimidobenzoyl-N-hydroxy-sulfosuccinimide ester, N-succinimidyl(4-iodoacetyl)aminobenzoate, sulfo-succinimidyl(4-iodoacetyl)aminobenzoate, succinimidyl-4-(p-maleimidophenyl)butyrate, sulfosuccinimidyl-4-(p-maleimidophenyl)butyrate, N-(γ-maleimidobutyryloxy)succinimide ester, N-(γ-maleimidobutyryloxy)sulfosuccinimide ester, succinimidyl 6-((iodoacetyl)amino)hexanoate, succinimidyl 6-(6-(((4-iodoacetyl)amino)hexanoyl)amino)hexanoate, succinimidyl 4-(((iodoacetyl)amino)methyl)cyclohexane-1-carboxylate, succinimidyl 6-((((4-iodoacetyl)amino)methyl)cyclohexane-1-carbonyl)amino)-hexanoate, and p-nitrophenyl iodoacetate). In some embodiments, the heterobifunctional cross-linker is modified with functional groups, rendering it soluble in aqueous solvents for delivery as an aqueous solution. Furthermore, in some embodiments, the aqueous solution contains additives (e.g., including, but not limited to, surfactants and block copolymers). In other embodiments, a multiplicity of heterobifunctional cross-linkers can be attached to a molecule, polymer or particle to serve as the cross-linking agent. In other embodiments, the heterobifunctional cross-linker is dissolved in an organic solvent (e.g., including, but not limited to, dimethyl sulfoxide).
In some embodiments, the covalent modifier is a photoactivatable crosslinker. Suitable photoactivatable crosslinkers include, but are not limited to, aryl azide N-((2-pyridyldithio)ethyl)-4-azidosalicylamide, 4-azido-2,3,5,6-tetrafluorobenzoic acid, succinimidyl ester, 4-azido-2,3,5,6-tetrafluorobenzoic acid, STP ester, benzophenone maleimide, succinimidyl ester of 4-benzoylbenzoic acid, N-5-Azido-2-Nitrobenzoyloxysuccinimide, N-Hydroxysulfosuccinimidyl-4-azidobenzoate, N-Hydroxysuccinimidyl-4-azidosalicylic acid, and (4-[p-Azidosalicylamido]butylamine).
The covalent modification agent may be applied to the matrix by any suitable method. In some embodiments, it is contemplated that the covalent modification agent is applied using either a pump (including syringes, ink jet printers, and electrojets) or spray, such as an aerosol spray. In other embodiments, the use of a brush including an air brush is contemplated. In other embodiments, a sponge is utilized.
Following application of the covalent modification agent to the matrix, a functionalized matrix is formed. In some embodiments, the functionalized matrix displays one or more reactive moieties, for example, azide moieties, succinimidyl moieties, alkyne moieties or any of the other reactive groups of the compounds described above.
In some embodiments, the matrix is modified by PEGylation with polyethylene glycol. It is contemplated that PEGylation can be used to control interaction of the matrix with the wound bed and to prevent nonspecific adsorption as desired. PEGylation can also be used to control delivery of the wound active agent from the matrix.
D. Wound Active Agents
In some embodiments, the matrices comprise one or more wound active agents as described in detail above. In some embodiments, the wound active agent or agents are noncovalently incorporated into the matrix. In some preferred embodiments, silver containing antimicrobials are incorporated into the functionalized matrix, for example, a polyelectrolyte multilayer as described above. In some embodiments, the wound active agent or agents are covalently immobilized on the matrix, for example, via a covalent modification agent.
In some embodiments, the one or more wound active agents are applied to form a gradient with respect to the wound modifying agent. In general, the gradients present a higher contraction of wound active agent at one or more first desired locations in the wound following application of the wound modifying agent to the wound and a lower concentration of wound active agent at one or second location in the wound following application of the matrix to the wound. For example, the concentrations of the wound active agents are layered in a wound bed in a gradient such that higher concentrations of a particular composition is greater proximal to the wound bed than distal to the wound bed in a vertical fashion. The converse, where concentrations of compositions is greater distal to the wound bed than proximal, is also contemplated. Concentration of compositions in a wound bed wherein a horizontal gradient is deposited is also contemplated. Topographical gradients are also contemplated, wherein compositions are deposited such that the concentrations of compositions in a wound bed or on a biocompatible particle follow the topography of the substrate, for example, a higher concentration of compositions is deposited in the valleys of undulations of an exemplary substrate compared to the peaks of the undulations.
In some embodiments, the gradient comprises a higher concentration of the wound active agent in the center of the matrix which transitions to a lower concentration of the wound active agent away from the center of the matrix. Accordingly, when the matrix is applied to a wound, the gradient results in a higher concentration of wound active agent in the center of the wound and a lower concentration of wound active agent as one moves to the periphery of the wound. In some embodiments, the gradient comprises a lower concentration of the wound active agent in the center of the matrix which transitions to a higher concentration of the wound active agent away from the center of the matrix. Accordingly, the gradient results in a lower concentration of wound active agent in the center of the wound and a higher concentration of wound active agent as one moves to the periphery of the wound. If two or more wound active agents are utilized, they can be presented as similar gradients or the gradients can be varied so that the concentrations of the two or more wound active agents vary across the wound. The gradients of high or low concentration can be any shape, such as circular, square, rectangular, oval, oblong, etc. so that the matrix and gradient can conform to a variety of wound shapes. For example, for long, incision type wound, the gradient may be centered on a longitudinal axis that extends along the length of the wound and can be centered on the wound. As another example, the gradient can be circular or oval-shaped for application to open type wounds, burns, sores and ulcers that are roughly circular or oval. In other embodiments, the gradients comprise a series of features arranged in a pattern. For example, the gradients can form a series of stripes or high and low concentrations of one or more wound active agents along a longitudinal axis of the matrix. Alternatively, the gradients can form a checkerboard pattern, array, concentric circles, overlapping circles or oval, etc.
E. Support Materials
In some embodiments, the matrices are formed on a support material. Suitable support materials include, but not limited to, solid supports formed from polymeric materials, elastomeric materials such PDMS, nylon, Teflon®, Gortex®, silk, polyurethane, and silicon, preferably medical grade silicon, PVDF, polyethylene oxide, and water soluble materials and polymers such as polyvinyl alcohol. In some embodiments, the polymer(s) used to form the polymer multilayer are different than the polymer(s) forming the support. In some embodiments, an additional layer of material, such as a water soluble material or polymer, is disposed between the polymer multilayer and the support. In some embodiments, the solid support is a wound dressing or biologic wound dressing that is compatible with functionalization by addition of a matrix material. Examples of commercially available wound dressings that can be modified by addition of a matrix as described below include, but are not limited to, Biobrane™, gauze, adhesive tape, bandages such as BandAids®, and other commercially available wound dressings including but not limited to COMPEEL®, DUODERM™, TAGADERM™ and OPSITE®. In some embodiments, the support is a silicon wafer, surfaces, such as glass or silicon wafers, that are coated with hydrophobic self assembled monolayer, fabrics, such as nylon fabrics, absorbent material, foam, a transparent thin film, a hydrogel, hydrofibers, hydrocolloids, alginate fibers, silica gel, sodium polyacrylate, potassium polyacrylamides and combinations thereof. In some embodiments, the supports comprise (e.g., is coated with or displays) a biological molecule selected from the group consisting of collagen, hyaluronic acid, glycosaminoglycans, keratin, fibronectin, vitronectin, laminin, and combinations or fragments thereof.
The matrices described above can be synthesized directly on the support material or transferred to the support material following synthesis, for example by transfer or stamping from a suitable support, such as an elastomeric support. There are several different methods that can be used to deposit polymer multilayers on a support. In some embodiments, the polymer multilayers are deposited onto a support by adsorption from solution, spraying, or spin coating. As described above, the matrices are preferably polymer multilayers, for example, polyelectrolyte multilayers. In some embodiments, the matrices preferably comprise one more wound active agents as described above and/or or nanoscale or microscale beads as described above. In some preferred embodiments, the wound active agent is one or more of silver nanoparticles, elemental silver, and silver containing compounds such as silver sulfadiazine and related compounds, preferably included in the concentration ranges described above.
In some embodiments, the present invention provides methods for transferring a polymer multilayer to a desired surface, such as soft surface. Such soft surfaces include, but are not limited to, skin, a wound bed, a tissue, artificial tissues including artificial skin tissues such as organotypically cultured skin tissues, Apligraf®, Dermagraft®, Oasis®, Transcyte®, Cryoskin® and Myskin®, artificial tissue matrices, gels comprising biomolecules, a wound dressing, and a biologic wound dressing. In some embodiments, the desired surface is contacted with a polymer multilayer, e.g., a polymer multilayer supported on a support and pressure is applied to effect transfer of the polymer multilayer from the support to the desired surface. In some embodiments, the pressure is from about 10 to about 500 kPa. In some embodiments, the transfer is performed in the substantial, or complete, absence of solution. Such dry transfer processes do not involve exposure of biological components of the desired surface to aqueous solutions containing species that may influence the activity of the biological components. In some embodiments, the transfer is performed through a gas phase. In some embodiments, the transfer is performed in an environment where the humidity is less than 100% of saturation. In some embodiments, the transfer is performed in the absence of liquid water.
Accordingly, in some embodiments, the present invention provides wound dressings comprising a support material having a surface oriented to a wound, wherein the surface oriented to the wound is modified with a matrix material of the present invention. When applied to a wound, the surface of the support material modified with the matrix material is put into contact with the wound bed.
In some embodiments, the support is a biologic wound dressing. In some embodiments, the biologic wound dressing is a type of wound dressing that comprises, e.g., is coated with or incorporates, cells (e.g., keratinocytes or fibroblasts and combinations thereof) and/or one or more biomolecules or fragments of biomolecules that can be placed in contact with the wound surface. The biomolecules may be provided in the form of an artificial tissue matrix comprising one or more biomolecules. Examples of such biomolecules include, but are not limited, to collagen, glycosaminoglycans, hyaluronic acid, laminin, vitronectin, fibronectin, keratin, antimicrobial polypeptides and combinations thereof. Examples of suitable biologic wound dressings include, but are not limited to, BIOBRANE™, Integra™, Apligraf®, Dermagraft®, Oasis®, Transcyte®, Cryoskin® and Myskin®.
In some embodiments, the support material is a biosynthetic wound dressing constructed of an elastomeric film (e.g., a silicone film) supported on support material, such as a fabric, preferably a polymeric fabric such as a nylon fabric. In some embodiments, the fabric is at least partially imbedded into the film (e.g., BioBrane™). In some embodiments, the elastomeric film is coated with one or more biomaterials, for example collagen, keratin, fibronectin, vitronectin, laminin and combinations thereof. Accordingly, the fabric presents to the wound bed a complex 3-D structure to which a biomaterial (e.g., collagen) has been bound, preferably chemically bound. In some preferred embodiments, the surface presented to the wound is further modified with a matrix material as described above. In some preferred embodiments, the matrix material is a polyelectrolyte membrane comprising a wound active agent, preferably selected from one or more of silver nanoparticles, elemental silver, and silver containing compounds such as silver sulfadiazine and related compounds, and preferably included in the concentration ranges described above. In some embodiments, the matrix further comprises nanoscale or microscale particles. The matrix can be synthesized directly on the collagen modified surface or transferred to the collagen modified surface by stamping as described above.
In some embodiments, the support material is an adhesive bandage comprising an adhesive portion (such as an adhesive strip) and an absorbent material, preferably treated or coated with a material (i.e., a non-adherent material) to prevent adhesion to the wound or comprising a layer of non-adherent material, such as Teflon®, on the surface of the absorbent pad that will contact the wound. In some embodiments, the support material is an absorbent pad (e.g., a gauze pad or polymer foam) preferably treated or coated with a material (i.e., a non-adherent material) to prevent adhesion to the wound or comprising a layer of non-adherent material, such as Teflon® or other suitable material, on the surface of the absorbent pad that will contact the wound. In some embodiments, the non-adhesive material or layer is breathable. In some embodiments, the wound dressing comprises a gel-forming agent, for example, a hydrocolloid such as sodium carboxymethylcellulose. In some embodiments, the absorbent pads or gel-forming agents are affixed to a material that is waterproof and/or breathable. Examples include, but are not limited, semipermeable polyurethane films. The waterproof and/or breathable material may further comprise an adhesive material for securing the bandage to the skin of a subject. The waterproof and/or breathable material preferably forms the outer surface of the adhesive bandage or pad, i.e., is the surface opposite of the surface comprising the matrix which contacts the wound. Examples of such adhesive bandages and absorbent pads include, but are not limited to, to adhesive bandages and pads from the Band-Aid® line of wound dressings, adhesive bandages and pads from the Nexcare® line of wound dressings, adhesive bandages and non-adhesive pads from the Kendall Curity Tefla® line of wound dressings, adhesive bandages and pads from the Tegaderm® line of wound dressings, adhesive bandages and pads from the Steri-Strip® line of wound dressings, the COMFEEL® line of wound dressings, adhesive bandages and pads, the Duoderm® line of wound dressings, adhesive bandages and pads, the TEGADERM™ line of wound dressings, adhesive bandages and pads, the OPSITE® line of wound dressings, adhesive bandages and pads, adhesive bandages and pads from the Allevyn™ line of wound dressings, adhesive bandages and pads from the Duoderm® line of wound dressings, and adhesive bandages and pads from the Xeroform® line of wound dressings. In some embodiments, the present invention provides methods and systems for producing the articles described above. In some embodiments, the polyelectrolyte multilayers are directly deposited on the solid support by any of the methods described in detail above. In some embodiments, the polyelectrolyte multilayers are deposited onto a stamp material, such as PDMS, and then transferred to the solid support by a stamping process as described in detail above.
F. Use of Matrices
In some embodiments, a matrix as described above is applied to a wound under conditions such that wound healing, as measured by wound contraction, is accelerated. In some embodiments, the matrix is functionalized just prior to application to a wound, while in other embodiments, the matrix is provided in a sterile package and is functionalized so that it is ready for application following removal from the sterile packaging. In some embodiments, the wound is pretreated or primed with a covalent modification agent that is reactive with the functionalization agent displayed by the functionalized matrix. For example, the wound may be modified as described in detail above with a covalent modification agent displaying a reactive azide group, while the matrix may be modified with a covalent modification agent displaying an alkyne group. In general, the wound may be modified with covalent modification agent A which displays reactive group X and the matrix displays covalent modification agent B which displays reactive group Y, wherein X and Y react with each other to form a covalent bond.
In some embodiments, the matrices are provided as kits, preferably with the matrix in a sterile package. In some embodiments, the matrix in the kit is pre-functionalized, while in other embodiments, the matrix is not functionalized and the kit comprises at least one functionalization agent along with instructions on how to functionalize the matrix. In some embodiments, the kits comprise a functionalization agent for functionalizing the wound bed prior to application of the matrix. In some embodiments the matrix providing in the kit comprises at least one wound active agent. In other embodiments, the kits comprise a wound active agent and instructions from applying the wound active agent to the matrix prior to application to a wound.

IV. Methods of Treating Wounds

A wound modifying agent with one or more wound active agents or matrix, as described above can be applied to all types of wounds. Furthermore, the compositions of the present invention can be applied to all types of wounds. Furthermore, a wound modifying agent with one or more wound active agents can be applied to skin, mucous membranes, body cavities, and to internal surfaces of bones, tissues, etc. that have been damaged. A wound modifying agent with one or more wound active agents can be used on wounds such as cuts, abrasions, ulcers, surgical incision sites, burns, and to treat other types of tissue damage. In some embodiments of the present invention, the compositions and methods described above enhance wound healing. The present invention contemplates that wound healing may be enhanced in a variety of ways. In some embodiments, the compositions and methods minimize contracture of the wound as to best favor function and cosmesis. In some embodiments, compositions and methods promote wound contracture to best favor function and cosmesis. In some embodiments, the compositions and methods promote vascularization. In some embodiments, the compositions and methods inhibit vascularization. In some embodiments, the compositions and methods promote fibrosis. In some embodiments, the compositions and methods inhibit fibrosis. In some embodiments, the compositions and methods promote epithelial coverage. In some embodiments, the compositions and methods inhibit epithelial coverage. In some embodiments, the compositions and methods of the present invention modulates one or properties of cells in the wound environment or in the immediate vicinity of the wound. The properties that are modulated, e.g., are increased or decreased, include, but are not limited to adhesion, migration, proliferation, differentiation, extracellular matrix secretion, phagocytosis, MMP activity, contraction, and combinations thereof.
The compositions of the present invention can be covered with a secondary dressing, or bandage, if desired to protect the layer or to provide additional moisture absorption, for example.
If desirable, the wound modifying agent with one or more wound active agents can be reapplied at a later time. It may be desirable to wound modifying agents having different formulations of wound active agents at different stages of wound healing.
In some embodiments, the immobilization of cytoactive factors and matrices immobilized on a wound bed using, for example, polyelectrolytes are evaluated in vitro and in vivo. In some embodiments, in vitro analysis comprising studying the ability of cytoactive factors to proliferate cell growth is evaluated in corneal epithelial cells and human vascular endothelial cells. In some embodiments, in vitro analysis comprises the construction of synthetic surfaces that mimic a wound bed, wherein said surfaces are created to comprise surface chemistries such as primary amine groups, carboxylic acids and thiol groups that are representative of the diversity of chemical functionality present in a wound bed. For example, ECM constituents and cytoactive factors are applied to the synthetic surfaces, and immobilization is confirmed by, for example, fluorescently labeled antibodies to the ECMs and cytoactive factors thereby immobilized. Further in vitro analysis includes, but is not limited to, proliferation dose response of the cytoactive factors and EMCs on the synthetic surfaces. In some embodiments, the in vitro assays are used to evaluate cytoactive factors that inhibit specific cell growth in a wound bed, thereby allowing for preferential recruitment and growth of those cell types optimal for wound healing and rapid return of tissue function and non-recruitment of antagonistic cell species.
In one embodiment, assays to evaluate immobilization strategies are performed ex vivo. In some embodiments, cutaneous wounds are harvested from mice. For example, a 6 mm surgical skin punch is used to create a cutaneous defect post-mortem, followed by removal of the entire wound bed (e.g., with underlying stromal muscular elements). Similar to the model in vitro system as previously described, the ex vivo model system includes linker chemistries and the like, and the immobilization strategies are evaluated, for example, using fluorescently labelled proteins. In some embodiments, the ex vivo model system comprises the immobilization of biotinylated BSA. In some embodiments, the surface of the wound bed is activated with a NHS ester by exposure to, for example, 1 mM BS₃. Biotinylated BSA (at, for example, 2 mg/ml) is subsequently added to the activated wound bed and allowed to attach for 2 hours. The biotinylated BSA immobilization is determined by FITC-labeled anti-biotin antibody. As such, once immobilization is verified (via fluorescence detection), evaluation of optimal chemical functionalities is determined for wound bed immobilization. For example, chemical functionalities are determined by replacing BS₃in the ex vivo model system with heterobifunctional cross-linkers as described herein that react with, for example, carboxylic acids, amines, and thiol groups found in the wound bed. Further, upon determination of optimal cross-linkers, the immobilization of cytoactive agents and extracellular matrix compounds as described herein are evaluated (e.g., using fluorescently labeled antibodies to immobilized compounds). It is contemplated that key parameters to a successful ex vivo evaluation include, but are not limited to, concentration of all immobilization compositions, buffer systems, and incubation times. Ex vivo evaluations constitute additional validation of in vivo wound bed healing systems.
In one embodiment, in vivo experiments further validate the wound bed healing methods as described herein. In some embodiments, the diabetic transgenic mouse db/db are used, as a phenotype of the diabetic mice is impaired wound healing. Polyelectrolytes, cytoactive agents, and extracellular matrices as described herein are applied to the db/db mice for optimization of wound healing. The present invention is not limited to a particular mechanism. Indeed, an understanding of the mechanism is not necessary to practice the present invention. Nonetheless, it is contemplated that optimized wound healing in diabetic mice provides a model system that correlates to wound healing for normal, cutaneous wounds. In one example, skin wounds are created in tandem on diabetic mice using a surgical skin punch. After wounding, test compounds are immobilized in one of the wounds, leaving the other as a control (e.g., BSA only). The test compounds are evaluated, for example as described in Example 3, thereby providing further information for useful in vivo compositions for wound bed healing. Information on the impact of the test compounds on wound healing is also obtained by, for example, evaluation of the wound bed for epithelial coverage, extent of formation of granulation tissue, collagen content, inflammation, fibroblast population and vascularization. Test compounds include, but are not limited to, the polyelectrolytes as described herein, extracellular matrix components (e.g., collagen, laminin, MATRIGEL, fibronectin, etc.) and cytoactive agents (e.g., EGF, VEGF, PDGF). To further characterize the wound bed, confocal microscopy is used to visualize cellular components in a three-dimensional space, thereby allowing for the visualization of the wound bed treatments in a native state.
In some embodiments, the present invention provides for the development of personalized therapeutic protocols for wound healing. For example, the compositions as described herein for wound healing are adapted for each individual wound, taking into account, for example, environmental factors, incubation times, application dynamics, wound bed structure, associated disease state (e.g., diabetes, etc.) and the like that make each wound bed unique. As such, the present invention provides for the alteration of surface chemistry/structure for each unique wound bed, using the compositions and methods as described herein.

EXPERIMENTAL

The examples below serve to further illustrate the invention, to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and/or methods claimed herein are made and evaluated, and are not intended to limit the scope of the invention. The examples are not intended to restrict the scope of the invention.

Example 1

Covalent Immobilization of a Protein to a Surface

To demonstrate that proteins can be covalently immobilized on model surfaces, bovine serum albumin (BSA) was used as the protein in the model system. Bovine serum albumin was biotinylated (BSA used as control) and covalently attached to gamma-amino propyl silanes (GAPS)-treated glass surfaces using the homobifunctional bifunctional cross-linker BS₃(1 mM for 15 min.). BS₃contains an amine-reactive N-hydroxysulfosuccinimide (NHS) ester at each end of an 8-carbon spacer arm. The NHS esters react with primary amines at pH 7-9 to form stable amide bonds, along with release of the N-hydroxysulfosuccinimide leaving group. For detection purposes, the biotinylated BSA was labeled with FITC-labeled anti-biotin antibodies and the BSA control was probed using FITC-antigoat antibodies.
The large fluorescent signal seen in FIG. 3 from the surfaces treated with biotinylated BSA and FITC-antibiotin antibody (diamonds) relative to controls (vertical lines, diagonal lines, bricks) confirms covalent attachment of the biotinylated BSA to the surface.

Example 2

Layer by Layer Deposition of Polyelectrolytes in Ex Vivo Wound Beds

Experiments depositing polyelectrolytes in wound bed explants from mice were performed. Cutaneous wounds from euthanized mice were harvested. The excised wounds were sequentially treated with aqueous solutions (0.5M NaCl, PBS at pH 7.0) containing polystyrene sulfonate (PSS, 1 mg/ml) and FITC-labeled poly allylamine hydrochloride (FITC-PAH, 1 mg/ml). Between adsorption steps, the wounds were treated rinsed with PBS. After each treatment with FITC-PAH, the intensity of fluorescence was recorded. As seen in FIG. 4, the growth in fluorescence after each treatment cycle with PSS and FITC-PAH demonstrates growth of a multilayered polyelectrolyte film on the wound bed, relative to control treatments.

Example 3

Use of Mesoscopic Cross-Linkers in Ex Vivo Wound Beds

Skin wounds are created in tandem on diabetic mice using a surgical skin punch. After wounding, one of the wounds is treated by contact with activated 10-micrometer diameter polystyrene beads with surfaces terminated in carboxylic acid groups. The activation of the carboxylic acid groups is achieved by incubation in EDC/NHS solution (200 mM/50 mM) in phosphate buffered saline (PBS) (10 mM phosphate, 120 mM NaCl, 2.7 mM KCl; pH 7.6) for 1 h at room temperature. Following activation, the beads were pipetted into the wound beads and allowed to incubate within the wound beds for 1 hr. After incubation, the wound beds are washed exhaustively with PBS, and then incubated with collagen (10 micromolar in PBS). The remaining wound is used as a control and treated as described above, but without activation of the beads with NHS/EDC. The size of the wound is measured after 2, 4, 6, 8 and 10 days. It is observed that the treated wound decreases in size faster than the control wound.

Example 4

Delivery of the Wound Modifying Agents Using Aerosol Sprays

Experiments depositing polyelectrolytes in wound bed explants from mice are performed using aerosol sprays. Cutaneous wounds from euthanized mice are harvested. The excised wounds are sequentially treated by the spraying (using aerosol spray cans) of aqueous solutions (0.5M NaCl, PBS at pH 7.0) containing polystyrene sulfonate (PSS, 1 mg/ml) or FITC-labeled poly allylamine hydrochloride (FITC-PAH, 1 mg/ml). Between spraying steps, the wounds are treated rinsed with PBS. After each treatment with FITC-PAH, the intensity of fluorescence is recorded. A measurement of the growth in fluorescence after each treatment cycle with PSS and FITC-PAH demonstrates growth of a multilayered polyelectrolyte film on the wound bed, relative to control treatments.

Example 5

Delivery of the Wound Modifying Agents Using Pumps

Experiments depositing polyelectrolytes in wound bed explants from mice are performed by sequentially delivering the wound healing agent to the wound beds using pumps. Cutaneous wounds from euthanized mice are harvested. A peristaltic pump (Fischer Scientific) is used to pump the liquid. The excised wounds are sequentially treated by pumping of aqueous solutions (0.5M NaCl, PBS at pH 7.0) containing polystyrene sulfonate (PSS, 1 mg/ml) or FITC-labeled poly allylamine hydrochloride (FITC-PAH, 1 mg/ml). Between pumping steps involving the polyelectrolytes, the wounds are treated rinsed with PBS using pumps. After each treatment with FITC-PAH, the intensity of fluorescence is recorded. A measurement of the growth in fluorescence after each treatment cycle with PSS and FITC-PAH demonstrates growth of a multilayered polyelectrolyte film on the wound bed, relative to control treatments.

Example 6

Delivery of the Wound Modifying Agents Using Stamps

Experiments depositing polyelectrolytes in wound bed explants from mice are performed by stamping of polyelectrolytes into the wound bed from elastomeric stamps. Elastomeric stamps are prepared from PDMS using parts A and B of a kit purchased from Dow-Corning. After curing the stamps in an oven at 100° C. for 12 hrs, the surface of the PDMS stamp is incubated with aqueous solutions (0.5M NaCl, PBS at pH 7.0) containing polystyrene sulfonate (PSS, 1 mg/ml) or FITC-labeled poly allylamine hydrochloride (FITC-PAH, 1 mg/ml). Between incubation steps involving the polyelectrolytes, the PDMS stamp is rinsed with PBS. After 10 layers each of PSS and PAH are deposited onto the stamp, the stamp is mechanically contacted with the cutaneous wounds harvested from euthanized mice. After removal of the stamp from the wound bed, the intensity of fluorescence of the wound bed is recorded. A measurement of the fluorescence relative to control treatments (PBS free of polyelectrolytes is incubated with the stamps) verifies the deposition of the wound modifying agent into the wound bed.

Example 7

Delivery of the Wound Modifying Agents to Surfaces Using Inkjet Technology

To demonstrate that inkjet technology can be used to deliver wound modifying agents to surfaces, aqueous solutions (in PBS) of FITC-labelled collagen are inkjet printed onto gamma-amino propyl silanes (GAPS)-treated glass surfaces that are activated using the homobifunctional bifunctional cross-linker BS₃(1 mM for 15 min.). BS₃contains an amine-reactive N-hydroxysulfosuccinimide (NHS) ester at each end of an 8-carbon spacer arm. The NHS esters react with primary amines at pH 7-9 to form stable amide bonds, along with release of the N-hydroxysulfosuccinimide leaving group. The surfaces are exhaustively washed with PBS. The fluorescence intensity of the surface is measurements to indicate attachment of the FITC-labelled collagen to the surface relative to a control experiment in which the activated surface is pre-exposed to BSA (1 mg/ml in PBS for 2 hrs), prior to inject printing of the FITC-labelled collagen.

Example 8

Delivery of the Wound Modifying Agents Using Air Brushes

Experiments depositing polyelectrolytes in wound bed explants from mice are performed using airbrushes. Cutaneous wounds from euthanized mice are harvested. The excised wounds are sequentially treated by the airbrushing of aqueous solutions (0.5M NaCl, PBS at pH 7.0) containing polystyrene sulfonate (PSS, 1 mg/ml) or FITC-labeled poly allylamine hydrochloride (FITC-PAH, 1 mg/ml). The airbrushes are prepared by pouring the aqueous polyelectrolyte solutions into the air brushes. Between brushing steps, the wounds are rinsed with PBS. After each treatment with FITC-PAH, the intensity of fluorescence is recorded. A measurement of the growth in fluorescence after each treatment cycle with PSS and FITC-PAH demonstrates growth of a multilayered polyelectrolyte film on the wound bed, relative to control treatments in which PBS solutions free of polyelectrolytes are air brushed onto the surfaces.

Example 9

Method to Modify the Topography of the Wound Bed

Skin wounds are created in tandem on diabetic mice using a surgical skin punch. After wounding, one of the wounds is treated by contact with a 1:1 mixture of activated 100-nanometer and 1 micrometer diameter polystyrene beads with surfaces terminated in carboxylic acid groups. The activation of the carboxylic acid groups is achieved by incubation in EDC/NHS solution (200 mM/50 mM) in phosphate buffered saline (PBS) (10 mM phosphate, 120 mM NaCl, 2.7 mM KCl; pH 7.6) for 1 hour at room temperature. Following activation, the mixture of beads are pipetted into the wound beads and allowed to incubate within the wound beds for 1 hr. After incubation, the wound beds are washed exhaustively with PBS, and then incubated in albumin (10 micromolar in PBS). The remaining wound is used as a control and treated as described above, but without activation of the beads with NHS/EDC. The size of the wound is measured after 2, 4, 6, 8 and 10 days. It is observed that the treated wound decreases in size faster than the control wound.

Example 10

Method to Covalently Modify the Wound Bed Using a Combination of Polyelectrolytes and Covalent Cross-Linking Agents

Skin wounds are created in tandem on diabetic mice using a surgical skin punch. After wounding, one of the wounds is treated by contact with activated 1-micrometer diameter polystyrene beads with surfaces terminated in carboxylic acid groups. The activation of the carboxylic acid groups is achieved by incubation in EDC/NHS solution (200 mM/50 mM) in phosphate buffered saline (PBS) (10 mM phosphate, 120 mM NaCl, 2.7 mM KCl; pH 7.6) for 1 hour at room temperature. Following activation, the beads are pipetted into the wound beds and allowed to incubate within the wound beds for 1 hr. After incubation, the wound beds are washed exhaustively with PBS, and then incubated with PAH, and then washed again in PBS. After PAH, the wound bed is sequentially treated with PSS and FITC-labelled PAH (as described above). Between each adsorption step, the wound bed is rinsed with PBS. Fluorescence measurements of the wound bed after each FITC-PAH adsorption step confirm immobilization of the PSS and PAH to the wound bed.

Example 11

Method to Modify the Mechanical Compliance of the Wound Bed

The mechanical compliance of the wound bed is modified by depositing polyelectrolytes into the wound bed and cross-linking the polyelectrolyte films. Experiments depositing polyelectrolytes in wound bed explants from mice are performed. Cutaneous wounds from euthanized mice are harvested. The excised wounds are sequentially treated with aqueous solutions (0.5M NaCl, PBS at pH 7.0) containing polystyrene sulfonate (PSS, 1 mg/ml) and FITC-labeled poly allylamine hydrochloride (FITC-PAH, 1 mg/ml). Between adsorption steps, the wounds are treated and rinsed with PBS. After treatment with the polyelectrolytes, BS3 (1 mM in PBS) is added to the wound bed and incubated for 1 hr. Upon poking with the end of a spatula, the rigidity of the wound bed is noticeably greater than a wound bed treated with polyelectrolytes without the final cross-linking step. The increase in ridigidity (decreased compliance) is confirmed by Atomic Force Microscopy.

Example 12

Method to Alter Intrinsic Compliance of Wound Bed

The mechanical compliance of the wound bed is altered by controlled application of enzyme(s) capable of degrading constituents of the extracellular matrix. Cutaneous wounds from euthanized mice are harvested. 10 μM concentration of collagenase is applied to the wound and allowed to incubate at room temperature for times ranging from 0 min-1 hour. The wound beds are then rinsed copiously with PBS. Wet Field force microscopy of the wound beds confirms that application of degradative enzymes increases the compliance (decreases rigidity) of the wound beds in a time dependent fashion.

Example 13

Nanometer-Thick Silver-Impregnated Polymeric Films Showing Selective Toxicity Towards Bacterial Growth and that Support Mammalian Cell Growth

Polyelectrolyte multilayers electrostatically assembled alternately from such weak polyacids as poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) were tuned to impregnate post-assembly with silver nanoparticles to levels where they kill bacteria effectively yet allow adhesion of mammalian cells on the films without measurable cytotoxicity. Silver ions (Ag⁺) were incorporated in the films by incubating them with bulk solution of a silver salt (e.g., silver nitrate). While the present invention is not limited to any particular mechanism, and an understanding of the mechanism is not necessary to practice the present invention, it is contemplated that Ag⁺ ions bound to the free carboxylic acid groups of PAA in the films by ion exchange with the acidic protons. Post binding, Ag⁺ in the films were reduced to zerovalent Ag nanoparticles by using an aqueous solution of a reducing agent. By changing the pH of the polyelectrolyte assembly solutions, the number of non-ionized carboxylic acid groups (and hence the amount of silver incorporated) in the PEMs post-assembly was effectively controlled. These silver-impregnated nanometer-thick films were then investigated for their interactions with NIH-3T3 cells, a highly adhesive murine fibroblast cell line, and Staphylococcus epidermidis, a gram-positive bacterium that occurs frequently on skin and in mucous membranes.
Silver loading in the PEMs could be varied from ˜24.2 μg/cm²to 0.4 μg/cm². Cytotoxicity to NIH-3T3 cells seeded on these films was correlated with the concentration of soluble silver in the PEMs, with augmented toxicity at higher silver concentrations, as shown in FIG. 8. PEMs prepared with relatively more ionized PAA entrapped lower amounts of silver and demonstrated reduced cytotoxicity. Further, their strongly ionically crosslinked architecture allowed better attachment and spreading of fibroblasts than PEMs prepared using weakly ionized PAA, as shown in FIG. 10. Bacteria killing efficiency of PEMs correlated to the amount of silver entrapped in the films (FIG. 9), with PEMs containing as little as ˜0.4 μg/cm²of silver providing up to 99.9999% kill in a water-borne assay. Furthermore, PEMs with this silver-loading did not exhibit measurable cytotoxicity to NIH-3T3 cells.

Example 14

Transfer to a Soft Surface with Microscale Beads

Introducing rigid microspheres in the polymer multilayers facilitates their transfer onto the dermis layer of a commercially available human skin graft—GammaGraft®. A PAH(PAA/PAH)10 multilayer, with fluorescent PAH and a PAH(PAA/PAH)5(PS μ-spheres)(PAH/PAA)5PAH multilayer, with fluorescent PS microspheres were stamped onto skin grafts. The portion of the multilayers that adhered to the grafts were accessed by fluorescence microscopy and imaging. The results (FIG. 12) showed that the polymer multilayers with microscale beads showed much better transfer to the skin graft than did the polymer multilayer without microscale beads.
All publications and patents mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described method and system of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention that are obvious to those skilled in relevant fields are intended to be within the scope of the following claims.

Claims

1.-29. (canceled)

30. A method for synthesizing a device for treatment of a wound, comprising:

a) assembling alternating layers of polyelectrolytes on a polymeric support to form a nanoscale polyelectrolyte multilayer on said support;

b) incubating said multilayer in bulk solution of a silver salt;

c) exposing said multilayer to a reducing agent to produce zerovalent silver ions.

31. The method of claim 30, wherein at least one of said polyelectrolytes comprises a solution containing poly(allylamine hydrochloride).

32. The method of claim 30, wherein at least one of said polyelectrolytes comprises a solution containing poly(acrylic acid).

33. The method of claim 30, wherein said bulk solution of a silver salt comprises silver nitrate.

34. The method of claim 30, wherein the concentration of Ag⁺ in said silver nitrate solution is about 5 mM.

35. The method of claim 32, wherein the pH of said poly(acrylic acid) solution is about 2.5 to 7.5.

36. A method for synthesizing a device for treatment of a wound, comprising:

a) assembling alternating layers of polyelectrolytes to form a nanoscale polyelectrolyte multilayer;

b) incubating said multilayer in bulk solution of a silver salt;

37. The method of claim 36, wherein at least one of said polyelectrolytes comprises a solution containing poly(allylamine hydrochloride).

38. The method of claim 36, wherein at least one of said polyelectrolytes comprises a solution containing poly(acrylic acid).

39. The method of claim 36, wherein said bulk solution of a silver salt comprises silver nitrate.

40. The method of claim 36, wherein the concentration of Ag⁺ in said silver nitrate solution is about 5 mM.

41. The method of claim 38, wherein the pH of said poly(acrylic acid) solution is about 2.5 to 7.5.