Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
  • A61L27/52—Hydrogels or hydrocolloids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/56—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule
  • A61K47/58—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. poly[meth]acrylate, polyacrylamide, polystyrene, polyvinylpyrrolidone, polyvinylalcohol or polystyrene sulfonic acid resin
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/0012—Galenical forms characterised by the site of application
  • A61K9/0019—Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner
  • A61K9/0024—Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
  • A61L15/24—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/42—Use of materials characterised by their function or physical properties
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L24/00—Surgical adhesives or cements; Adhesives for colostomy devices
  • A61L24/001—Use of materials characterised by their function or physical properties
  • A61L24/0031—Hydrogels or hydrocolloids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L24/00—Surgical adhesives or cements; Adhesives for colostomy devices
  • A61L24/04—Surgical adhesives or cements; Adhesives for colostomy devices containing macromolecular materials
  • A61L24/046—Surgical adhesives or cements; Adhesives for colostomy devices containing macromolecular materials obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/14—Macromolecular materials
  • A61L27/16—Macromolecular materials obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/36—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix
  • A61L27/38—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells
  • A61L27/3804—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
  • A61L31/04—Macromolecular materials
  • A61L31/06—Macromolecular materials obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
  • A61L31/08—Materials for coatings
  • A61L31/10—Macromolecular materials
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
  • A61L31/14—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
  • A61L31/145—Hydrogels or hydrocolloids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/34—Esters containing nitrogen, e.g. N,N-dimethylaminoethyl (meth)acrylate
  • C08F220/36—Esters containing nitrogen, e.g. N,N-dimethylaminoethyl (meth)acrylate containing oxygen in addition to the carboxy oxygen, e.g. 2-N-morpholinoethyl (meth)acrylate or 2-isocyanatoethyl (meth)acrylate
  • C08F220/365—Esters containing nitrogen, e.g. N,N-dimethylaminoethyl (meth)acrylate containing oxygen in addition to the carboxy oxygen, e.g. 2-N-morpholinoethyl (meth)acrylate or 2-isocyanatoethyl (meth)acrylate containing further carboxylic moieties
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G81/00—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers
  • C08G81/02—Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers at least one of the polymers being obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C08G81/021—Block or graft polymers containing only sequences of polymers of C08C or C08F
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N5/00—Undifferentiated human, animal or plant cells, e.g. cell lines; Tissues; Cultivation or maintenance thereof; Culture media therefor
  • C12N5/0018—Culture media for cell or tissue culture
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N2533/00—Supports or coatings for cell culture, characterised by material
  • C12N2533/30—Synthetic polymers
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N2539/00—Supports and/or coatings for cell culture characterised by properties

Definitions

• Hydrogels have long been of interest for biological and biomaterial applications due to their high water content that mimics the interstitial tissue environment, ensures high diffusive permeability, and provides biomimetic mechanical strengths. Particular interest has been given to PEG hydrogels and poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels because, in addition to the general properties of hydrogels, they are also commonly considered to be low fouling, bioinert, and versatile.
• PEG hydrogels and poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels because, in addition to the general properties of hydrogels, they are also commonly considered to be low fouling, bioinert, and versatile.
• pHEMA hydrogels have found use in and been studied for applications such as contact lenses, artificial cornea, drug delivery vehicles, cartilage substitutes, and tissue scaffolds, among others.
• the hydration of pHEMA is lower than that of native tissue, and its fouling, while low, is higher than other nonfouling materials.
• pHEMA functionalization via the hydroxyl group is generally difficult.
• PEG hydrogels are routinely used, and can only be modified for applications that require a bioinert background with specific added bioactive functionalities for controlled in vitro and in vivo uses when additional functional groups are introduced into PEG hydrogels.
• PEG is susceptible to oxidation.
• the susceptibility of PEG to oxidative damage reduces its utility for applications that require long-term material stability. For applications in which maximal biological stability and nonfouling are required, however, PEG-based materials are insufficient.
• zwitterionic compounds including poly(carboxybetaine methacrylate), have been demonstrated to be ultra-low-fouling, meaning that surfaces coated with these polymers allow less than 5ng/cm 2 protein adsorption. Because of the high hydration and ultralow fouling properties of zwitterionic materials, zwitterionic hydrogels are of interest as hydrogels with superior suitability for biomedical applications. The zwitterionic hydrogels studied so far, however, have shown low mechanical strength, which limits their potential biological uses.
• the present invention seeks to fulfill this need and provides further related advantages.
• the present invention provides functionalized zwitterionic and mixed charge polymers and copolymers, methods for making the polymers and copolymers, hydrogels prepared from the functionalized zwitterionic and mixed charge polymers and copolymers, methods for making the hydrogels, methods for using the hydrogels for in vitro and in vivo cell culture, and zwitterionic and mixed charge polymers and copolymers for administration for therapeutic agents.
• the invention provides functionalized zwitterionic polymers and copolymers and functionalized mixed charge copolymers.
• the invention provides a functionalized polymer, comprising a core having two or more polymeric branches covalently coupled to and extending from the core, wherein the polymeric branches comprises constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more functional groups effective for covalently coupling the polymer to a material capable of forming a covalent bond with the one or more functionalize groups.
• the polymer comprises three, four, five, or six polymeric branches.
• the number of branches can be varied and depends in the nature of the core and the branches themselves.
• the branches are branched.
• the constitutional units are zwitterionic constitutional units.
• the constitutional units are mixed charge constitutional units.
• the zwitterionic polymers and mixed charge copolymers may further include other constitutional units (e.g., the zwitterionic polymers can be copolymers).
• Suitable other constitutional units include constitutional units that include functional groups for imparting reactivity to the copolymers, or other groups to impart desired properties to the copolymer (e.g., anionic groups, cationic groups, neutral groups, hydrophobic groups, hydrophilic groups).
• the functional group is positioned at the terminus of the polymeric branch. In other embodiments, the functional group is positioned along the backbone of the polymeric branch. In some embodiments, one or more of the constitutional units comprise the functional group.
• the number of functional groups in the polymer or the polymer branch can be controlled to achieve the desired overall functionality of the polymer or branch and will depend on the polymers ultimate use.
• the functional group is a thiol. In other embodiments, the functional group is one of a reactive pair. In these embodiments, the functional group is one of a reactive pair selected from an azide and an alkyne, an azide and an alkene, a thiol and a maleimide, or a thiol and a dissulfide.
• zwitterionic and mixed charge hydrogels are provided.
• the hydrogel comprises a first polymer covalently coupled to a second polymer, wherein the first polymer comprises a first core having two or more polymeric branches covalently coupled to and extending from the first core, wherein the polymeric branches comprise first constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more first functional groups effective for covalently coupling the first polymer to the second polymer, wherein the second polymer comprises a second core having two or more polymeric branches covalently coupled to and extending from the second core, wherein the polymeric branches comprise second constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more second functional groups effective for covalently coupling the second polymer to the first polymer; and wherein the hydrogel comprises covalent bonds linking the first and second polymers formed by reaction of the first and second functional groups.
• the hydrogel comprises a first polymer covalently coupled to a second polymer, wherein the first polymer comprises a first core having two or more polymeric branches covalently coupled to and extending from the first core, wherein the polymeric branches comprise first constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more first functional groups effective for covalently coupling the first polymer to the second polymer, wherein the second polymer comprises a second core having two or more polymeric branches covalently coupled to and extending from the second core, wherein the polymeric branches comprise second constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more second functional groups effective for covalently coupling the second polymer to the first polymer; and wherein the hydrogel comprises covalent bonds linking the first and second polymers via a crosslinking agent having two or more third functional groups, wherein the covalent bonds linking
• the nature of crosslinking can be varied.
• the first and second polymers are different, have different functional groups, and are crosslinked by the crosslinking agent with suitably reactive functional groups.
• the first and second polymers are the same, have the same functional groups, and are crosslinked by the crosslinking agent with suitably reactive functional groups.
• the first and second functional groups are the same.
• the first functional group is a thiol
• the second functional group is a thiol
• the third functional group is a thiol or a dissulfide.
• the first and third functional groups and the second and third functional groups are click chemistry reactive pairs.
• the first and third functional groups are selected from an azide and an alkyne, an azide and an alkene, a thiol and a maleimide, or a thiol and a dissulfide.
• the second and third functional groups are selected from an azide and an alkyne, an azide and an alkene, a thiol and a maleimide, or a thiol and a dissulfide.
• the first polymer comprises three, four, five, or six polymeric branches.
• the first constitutional units are zwitterionic constitutional units. In other embodiments, the first constitutional units are mixed charge constitutional units.
• the first functional groups are positioned at the terminus of the polymeric branch. In other embodiments, the first functional groups are positioned along the backbone of the polymeric branch. In certain embodiments, the first constitutional units comprise the first functional group.
• the second polymer comprises three, four, five, or six polymeric branches.
• the second constitutional units are zwitterionic constitutional units.
• the second constitutional units are mixed charge constitutional units.
• the second functional groups are positioned at the terminus of the polymeric branch. In other embodiments, the second functional groups are positioned along the backbone of the polymeric branch. In certain embodiments, the second constitutional units comprise the second functional group.
• the first and second functional groups are the same. In certain embodiments, the first functional group is a thiol and second functional group is a thiol. In other embodiments, the first and second functional groups are different. In certain embodiments, the first and second functional groups are a click chemistry reactive pair. Representative pairs include an azide and an alkyne, an azide and an alkene, a thiol and a maleimide, or a thiol and a dissulfide.
• the hydrogel of the invention may advantageously include additional components.
• the hydrogels further include cells, viruses, bacteria, and components thereof, or their genetically altered variants.
• Representative cells include natural cells and their genetically modified counterparts, such as exocrine secretory epithelial cells, hormone secreting cells, keratinizing epithelial cells, wet stratified barrier epithelial cells, sensory transducer cells, autonomic neuron cells, sense organ and peripheral neuron supporting cells, neurons and glial cells, lens cells, hepatocytes, adipocytes, lipocytes, barrier function cells, kidney cells, heart cells, extracellular matrix cells, contractile cells, blood and immune system cells such as erythrocytes, monocytes, neutrophils, mast cells, T cells, stem cells, germ cells, nurse cells, interstitial cells, progenitor cells, hematopoietic stem cells.
• Representative viruses include DNA viruses, RNA viruses, reverse transcriptase viruses, retroviruses, and adenoviruses.
• Representative bacteria include pathogenic bacteria, Gram-positive bacteria, Gram-negative bacteria, cyanobacteria.
• Representative bacteria species include clostridial species, S. typhimurium, and E. coli.
• the hydrogels of the invention include oligonucleotides (DNAs and RNAs), lipoplexes, polymersomes, polyplexes, dendrimers, inorganic particles.
• the hydrogels of the invention include proteins, peptides, polysaccharides, or small molecules.
• the hydrogels of the invention include a therapeutic or diagnostic agent.
• the hydrogels of the invention include a nanomaterial. Surfaces Treated and Devices Made with Zwitterionic and Mixed Charge Polymeric Hydrogels
• the invention provides substrates treated a hydrogel of the invention.
• the invention provides a substrate having a surface, wherein at least a portion of the surface is coated with the hydrogel. In certain embodiments, the surface is entirely coated with the hydrogel.
• the invention provides devices (e.g., medical devices) formed at least in part from the hydrogels of the invention or devices (e.g., medical devices) that incorporate the hydrogels of the invention.
• the devices are made entirely or partially from the hydrogels of the invention.
• Representative substrates and devices include the following: implantable biosensor, wound care device, sealant, contact lens, dental implant, orthopedic device (artificial joint, artificial bone, artificial ligament, artificial tendon), cardiovascular device (cathether, artificial valve, artificial vessel, artificial stent, LVAD, rhythm management device), gastroenterology device (feeding tube, alimentary canal clip, gastro-intestinal sleeve, gastric balloon), OB/Gyn device (implantable birth control device, vaginal sling), nephrology device (anastomotic connector, subdermal port), neurosurgery device (nerve guidance tube, cerebrospinal fluid drain or shunt), dermatology device (skin repair device), ophthalmic device (shunt), otorhinolaryngology device (stent, cochlear implant, tube, shunt, spreader), intra-ocular lens, aesthetic implant (breast implant, nasal implant, cheek implant), neurologic implant (nerve stimulation device), cochlear implant, nerve conduit, hormone control implant
• the invention provides uses for the zwitterionic and mixed charge polymeric hydrogels.
• the invention provides a medium for protection, preservation, or growth of cells comprising the hydrogel.
• the medium can further include one or more nutrients or growth factors.
• the medium can be used in vitro or in vivo.
• the invention provides a surgical sealant comprising the hydrogel.
• the invention provides a surgical anti-adherence coating comprising the hydrogel.
• the invention provides a surgical filler comprising the hydrogel.
• the invention provides a wound dressing comprising the hydrogel.
• the invention provides an aesthetic filler comprising the hydrogel.
• the invention provides an aesthetic filler pre-formed to a specific shape comprising the hydrogel.
• the invention provides an orthopedic soft tissue replacement (e.g., for cartilage or spinal discs) comprising the hydrogel.
• the invention provides a tissue growth scaffold, comprising the hydrogel.
• the scaffold can be used in vitro or in vivo.
• the invention provides a medical device formed at least in part from a hydrogel.
• the invention provides a medical device incorporating a hydrogel.
• the invention provides methods for making zwitterionic and mixed charge polymeric hydrogels.
• the invention provides a method for forming a hydrogel, comprising reacting a first polymer with a second polymer to provide a hydrogel, wherein the first polymer comprises a first core having two or more polymeric branches covalently coupled to and extending from the first core, wherein the polymeric branches comprise first constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more first functional groups effective for covalently coupling the first polymer to the second polymer, wherein the second polymer comprises a second core having two or more polymeric branches covalently coupled to and extending from the second core, wherein the polymeric branches comprise second constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more second functional groups effective for covalently coupling the second polymer to the first polymer; and wherein the hydrogel is formed by covalent bond formation between the first and second functional groups.
• the hydrogel is formed in situ (e.g., in vivo). In other embodiments, the hydrogel is formed in a vessel. In either embodiment, the hydrogel can be used for cell culture.
• the invention provides a method for forming a hydrogel in vivo, comprising:
• the first polymer comprises a first core having two or more polymeric branches covalently coupled to and extending from the first core, wherein the polymeric branches comprise first constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more first functional groups effective for covalently coupling the first polymer to the second polymer, wherein the second polymer comprises a second core having two or more polymeric branches covalently coupled to and extending from the second core, wherein the polymeric branches comprise second constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more second functional groups effective for covalently coupling the second polymer to the first polymer; and
• hydrogel is formed by covalent bond formation between the first and second functional groups.
• the first polymer and second polymer are disposed at the site by injection, spray, pouring, and dipping.
• the invention provides a method for forming a hydrogel, comprising reacting a first polymer, a second polymer, and a crosslinking agent to provide a hydrogel
• the first polymer comprises a first core having two or more polymeric branches covalently coupled to and extending from the first core, wherein the polymeric branches comprise first constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more first functional groups effective for covalently coupling the first polymer to the crosslinking agent
• the second polymer comprises a second core having two or more polymeric branches covalently coupled to and extending from the second core, wherein the polymeric branches comprise second constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the two or more polymeric branches each comprise one or more second functional groups effective for covalently coupling the second polymer to the crosslinking agent
• the crosslinking agent comprises two or more
• the first and second functional groups are the same; the first functional group is a thiol, the second functional group is a thiol, and the third functional group is a thiol or a disulfide; and the first and third functional groups and the second and third functional groups are click chemistry reactive pairs.
• the first and third functional groups are selected from an azide and an alkyne, an azide and an alkene, a thiol and a maleimide, or a thiol and a dissulfide.
• the second and third functional groups are selected from an azide and an alkyne, an azide and an alkene, a thiol and a maleimide, or a thiol and a dissulfide.
• the first polymer comprises three, four, five, or six polymeric branches.
• the first constitutional units are zwitterionic constitutional units. In others of these embodiments, the first constitutional units are mixed charge constitutional units.
• the first functional groups are positioned at the terminus of the polymeric branch. In other embodiments, the first functional groups are positioned along the backbone of the polymeric branch. In certain embodiments, one or more of the first constitutional units comprise the first functional group.
• the second polymer comprises three, four, five, or six polymeric branches.
• the second constitutional units are zwitterionic constitutional units. In others of these embodiments, the second constitutional units are mixed charge constitutional units.
• the second functional groups are positioned at the terminus of the polymeric branch. In other embodiments, the second functional groups are positioned along the backbone of the polymeric branch. In certain embodiments, one or more of the second constitutional units comprise the second functional group.
• the first and second functional groups are the same. In certain embodiments, the first functional group is a thiol and second functional group is a thiol.
• the first and second functional groups are different.
• the first and second functional groups are a click chemistry reactive pair.
• the first and second functional groups are selected from an azide and an alkyne, an azide and an alkene, a thiol and a maleimide, or a thiol and a dissulfide. Zwitterionic and Mixed Charge Star Polymer Therapeutic Agent Conjugates
• the invention provides zwitterionic and mixed charge star polymer therapeutic agent conjugates.
• the invention provides a polymer, comprising a core having two or more polymeric branches covalently coupled to and extending from the core, wherein the polymeric branches comprises constitutional units selected from the group consisting of zwitterionic constitutional units and mixed charge constitutional units, and wherein the zwitterionic constitutional units and the mixed charge constitutional units comprise a therapeutic agent covalently coupled thereto.
• the therapeutic agent is covalently coupled to the constitutional unit by a hydrolyzable bond.
• the polymer comprises three, four, five, or six polymeric branches.
• the constitutional units are zwitterionic constitutional units. In other embodiments, the constitutional units are mixed charge constitutional units.
• a method for administering a therapeutic agent to a subject is provided.
• a therapeutically effective amount of a polymer of the invention having a therapeutic agent covalently coupled thereto is administered to a subject (e.g., a warm-blooded animal, such as a human) in need thereof.
• administering the polymer comprises systemic, topical, or local administration. In certain embodiments, administering the polymer comprises inhalation, oral, and transdermal administration. In certain embodiments, administering the polymer comprises intravenous injection, intramuscular injection, subcutaneous injection, intraperitoneal injection, or local injection.
• FIGURE 1 is a schematic illustration of the synthesis of a representative star polymer of the invention having zwitterionic (polycarboxybetaine) branches.
• the branches are shown terminating with a bromomethyl group, which is the radical initiator group for continued polymerization (e.g., atom transfer radical polymerization, ATRP).
• a bromomethyl group which is the radical initiator group for continued polymerization (e.g., atom transfer radical polymerization, ATRP).
• FIGURE 2 is a schematic illustration of the synthesis of a representative star polymer of the invention having zwitterionic (polycarboxybetaine) branches terminated with a thiol group (-CH 2 -SH).
• This star polymer was prepared from the star polymer illustrated in FIGURE 1 by click chemistry (reaction of the star polymer with sodium azide and 3-thioacetylene).
• FIGURES 3 A and 3B schematically illustrate the preparation of a representative hydrogel of the invention prepared from suitably functionalized star polymers of the invention.
• FIGURE 3A illustrates the syntheses of two representative star polymers of the invention: (a) a star polymer having zwitterionic (polycarboxybetaine) branches terminated with a thiol group (-CH 2 -SH) denoted pCB-A; and (b) a star polymer having zwitterionic (polycarboxybetaine) branches terminated with a pyridyl disulfide group (-CH 2 -S-S-C 5 H 4 N) denoted pCB-B.
• FIGURE 3B illustrates the preparation of representative hydrogels of the invention prepared from reaction of the star polymers (pCB-A and pCB-B) illustrated in FIGURE 3A.
• the hydrogels can be formed by simply mixing pCB-A with pCB-B in the presence of cells.
• FIGURES 4A-4D present data for encapsulated islets cells cultured in a representative hydrogel (pCB hydrogel) of the invention.
• FIGURE 4A is an image showing the results of a LIVE/DEAD assay performed on encapsulated islets within pCB hydrogels after 18-day in vitro culture. Scale bar: 300 ⁇ . Effects of hydrogel encapsulation of islet cells is shown in FIGURES 4B-4D.
• * indicates significant difference from control islets (without hydrogel, p ⁇ 0.05). Mean ⁇ SEM.
• FIGURES 5A and 5B present data for encapsulated peripheral blood stem cell (PBSC) cells cultured in a representative hydrogel (pCB hydrogel) of the invention.
• FIGURE 5A illustrates hydrogel modulus over time (hydrogel degradation).
• FIGURE 5B is an image showing the results of a LIVE/DEAD assay performed on encapsulated PBSC cells within the pCB hydrogels after 7-day in vitro culture.
• FIGURE 6 is a schematic illustration of the release of a representative therapeutic agent from a representative star polymer of the invention having zwitterionic (polycarboxybetaine) branches.
• the branches are further extended by extension polymerization with CBMA to provide branches having constitutional units that are zwitterionic in addition to constitutional units bearing the therapeutic agent.
• the star polymer illustrated in FIGURE 6 is a block copolymer.
• the star polymer is a random copolymer prepared by copolymerization of zwitterionic monomers (e.g., CBMA) and zwitterionic- therapeutic agent monomers (e.g., CBMA-therapeutic agent).
• zwitterionic monomers e.g., CBMA
• CBMA-therapeutic agent e.g., CBMA-therapeutic agent
• the therapeutic agent is released. Hydrolysis of the star polymer and release of the therapeutic agent regenerates a zwitterionic constitutional unit in the star polymer.
• the therapeutic agent is ibuprophen
• the monomer for synthesizing the star polymer capable of releasing ibuprophen is prepared by condensation of CBMA with ibuprofen.
• FIGURE 7 is a schematic illustration of the preparation of a representative star pCB of the invention useful for making hydrogels for cell encapsulation.
• FIGURE 8 is compares viability of T cells encapsulated within representative pCB hydrogels of the invention.
• the present invention provides zwitterionic and mixed charge star polymers and copolymers, functionalized zwitterionic and mixed charge star polymers and copolymers useful for therapeutic agent delivery and hydrogel formations, zwitterionic and mixed charge star polymers and copolymers having therapeutic agents covalently coupled thereto for therapeutic agent delivery, and hydrogels prepared from the functionalized zwitterionic and mixed charge star polymers.
• zwitterionic polymer or copolymer refers to a polymer or copolymer having zwitterionic constitutional units. Zwitterionic constitutional units have pendant groups (i.e., groups pendant from the polymer backbone) that include zwitterionic groups.
• Representative zwitterionic pendant groups include carboxybetaine groups (e.g., -R a -N + (R b )(R c )-R d -C0 2 ⁇ , where R a is a linker group that covalently couples the polymer backbone to the cationic nitrogen center of the carboxybetaine groups, R b and R c are nitrogen substituents, Rj is a linker group that covalently couples the cationic nitrogen center to the carboxy group of the carboxybetaine group).
• carboxybetaine groups e.g., -R a -N + (R b )(R c )-R d -C0 2 ⁇
• R a is a linker group that covalently couples the polymer backbone to the cationic nitrogen center of the carboxybetaine groups
• R b and R c are nitrogen substituents
• Rj is a linker group that covalently couples the cationic nitrogen center to the carboxy group
• mixed charge copolymer refers to a copolymer having substantially equal numbers of positively charged constitutional units and negatively charged constitutional units to provide a copolymer that is substantially electronically neutral.
• the mixed charge copolymer are random copolymers that do not have extensive regions along the polymer backbone that are positively charged or negatively charged (i.e., the positively and negatively charged constitutional units are relatively uniformly distributed along the polymer backbone).
• Representative mixed charge pendant groups include carboxy groups (e.g., -R a -C0 2 " , where R a is a linker group that covalently couples the carboxy group to the polymer backbone) and amino groups (e.g., -R a -N + (R b )(R c )(R d ), where R a is a linker group that covalently couples the cationic nitrogen center to the polymer backbone, and R b , R c , and Rj are nitrogen substituents).
• carboxy groups e.g., -R a -C0 2 "
• R a is a linker group that covalently couples the carboxy group to the polymer backbone
• amino groups e.g., -R a -N + (R b )(R c )(R d )
• R a is a linker group that covalently couples the cationic nitrogen center to the polymer backbone
• star polymer or copolymer refers to a branched polymer or copolymer in which two or more polymer or copolymer branches extend from a core.
• Representative star polymers and copolymers of the invention include two, three, four, five, six, or more branches extending from the core.
• the core is a group of atoms having two or more functional groups from which the branches can be extended by polymerization.
• Representative cores have two, three, four, five, six, or more functional groups from which the branches can be extended.
• the branches are zwitterionic polymeric or copolymeric branches.
• the branches are mixed charge copolymeric branches
• the term "functionalized polymer or copolymer” refers to a polymer of copolymer that includes a functional group that renders to polymer or copolymer reactive to covalent coupling to another polymer of copolymer that is also a functionalized polymer or copolymer.
• functionalized star polymers and copolymers of the invention react through their functional groups to form covalent bonds that covalently couple the polymers and copolymers (e.g., crosslink the polymer and copolymers).
• the functional groups of the first and second polymers or copolymers (i.e., the first and second functional groups, respectively) have complimentary reactivity.
• the first and second functional groups are reactive pairs.
• the first and second functional groups react on mixing at a temperature between room temperature and physiological temperature to form a bond (e.g., without external stimulus). Suitable such reactive pairs are known in the art. Representative useful reactive pairs include thiol/maleimide and click chemistry reactive pairs (e.g., azides/alkynes and azides/alkenes).
• constitutional unit refers to an atom or group of atoms in a polymer that includes a part of the polymer chain together with its pendant atoms or groups of atoms, if any.
• the constitutional unit can refer to a repeat unit.
• the constitutional unit can also refer to an end group on a polymer chain.
• the constitutional unit of polyethylene glycol can be -CH 2 CH 2 0- corresponding to a repeat unit, or -CH2CH2OH corresponding to an end group.
• repeat unit corresponds to the smallest constitutional unit, the repetition of which constitutes a regular macromolecule (or oligomer molecule or block).
• end group refers to a constitutional unit with only one attachment to a polymer chain, located at the end of a polymer.
• the end group can be derived from a monomer unit at the end of the polymer, once the monomer unit has been polymerized.
• the end group can be a part of a chain transfer agent or initiating agent that was used to synthesize the polymer.
• the term "monomer” is a polymerizable compound that, on polymerization, contributes one or more constitutional units in the structure of the polymer.
• polymer refers to the product that is the result of polymerization of a single monomer.
• copolymer refers to a polymer that is the result of polymerization of two or more different monomers.
• the number and the nature of each constitutional unit can be separately controlled in a copolymer.
• the constitutional units can be disposed in a purely random, an alternating random, a regular alternating, a regular block, or a random block configuration unless expressly stated to be otherwise.
• a purely random configuration can, for example, be: x-x-y-z-x-y-y-z-y-z-z... or y-z-x-y-z-y-z-x-x....
• An alternating random configuration can be: x-y-x-z-y-x-y-z-y-x-z..., and a regular alternating configuration can be: x-y-z-x-y-z-x-y-z ....
• the invention provides functionalized zwitterionic and mixed charge polymers and copolymers.
• the functionalized zwitterionic and mixed charge polymers and copolymers of the invention are functionalized zwitterionic star and mixed charge star polymers and copolymers.
• the branches can be any zwitterionic or mixed charge polymers and their precursors that can be converted to zwitterionic or mixed charge polymers via hydrolysis, ultraviolet irradiation, or heat.
• the zwitterionic or mixed charge polymers can be obtained by any polymerization method effective for polymerization of unsaturated monomers, including atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain- transfer polymerization (RAFT), photo-polymerization, ring-opening polymerization (ROP), condensation, Michael addition, branch generation/propagation reaction, or other reactions.
• ATRP atom transfer radical polymerization
• RAFT reversible addition-fragmentation chain- transfer polymerization
• ROP ring-opening polymerization
• the polymers having terminal functional groups are able to specifically bind to a binding partner and at the same time avoid nonspecific biofouling, which is imparted to the polymers by their zwitterionic or mixed charge structures.
• the polymers of the invention can be converted to further functionalized polymers useful for making hydrogels of the invention, by complimentary coupling chemistries (e.g., click chemistries, thiol exchange reactions, reductive reactions, and other chemistries known in the art).
• These functional end groups can be pre- and post-modified after the branches are created.
• the functionalized polymers, and copolymers of the invention are polymers prepared from polymerization of suitable polymerizable zwitterionic monomers.
• the polymer or copolymer has repeating units having formula (I): (I)
• R4 is selected from hydrogen, fluorine, trifluoromethyl, C1-C6 alkyl, and C6-C12 aryl groups;
• R 5 and R 6 are independently selected from alkyl and aryl, or taken together with the nitrogen to which they are attached form a cationic center;
• L 4 is a linker that covalently couples the cationic center [N + (R 5 )(R6)] to the polymer backbone [-(CH 2 -CR4) n -];
• a 2 is C, SO, S0 2 , P, or PO;
• n is an integer from 5 to about 10,000;
• * represents the point at which the repeating unit is covalently linked to an adjacent repeating unit or a functional group useful for forming hydrogels.
• the pendant zwitterionic groups are internal salts and M + and X " are absent.
• R 4 is C1-C3 alkyl.
• R5 and R 6 are independently selected from alkyl and aryl, or taken together with the nitrogen to which they are attached form a cationic center.
• R 5 and Re are C1-C3 alkyl.
• L5 is -(CH 2 ) n -, where n is an integer from 1 to 20.
• a 2 is C or SO.
• n is an integer from 5 to about 5,000.
• the zwitterionic polymers and copolymers of the invention can be prepared by polymerization of monomers having formula (II):
• the invention provides mixed charge copolymers prepared from copolymerization of ion pair comonomers.
• the mixed charge copolymers having a polymer backbone, a plurality of positively charged repeating units, and a plurality of negatively charged repeating units.
• these copolymers may be prepared by polymerization of ion-pair comonomers.
• the mixed charge copolymer includes a plurality of positively charged repeating units, and a plurality of negatively charged repeating units.
• the mixed charge copolymer is substantially electronically neutral.
• substantially electronically neutral refers to a copolymer that imparts advantageous nonfouling properties to the copolymer.
• a substantially electronically neutral copolymer is a copolymer having a net charge of substantially zero (i.e., a copolymer about the same number of positively charged repeating units and negatively charged repeating units).
• the ratio of the number of positively charged repeating units to the number of the negatively charged repeating units is from about 1 : 1.1 to about 1 :0.5.
• the ratio of the number of positively charged repeating units to the number of the negatively charged repeating units is from about 1 : 1.1 to about 1 :0.7. In one embodiment, the ratio of the number of positively charged repeating units to the number of the negatively charged repeating units is from about 1 : 1.1 to about 1 :0.9. In one embodiment, the mixed charge copolymers are prepared from copolymerization of suitable polymerizable ion pair comonomers.
• the mixed charge copolymer has repeating units having formula (VI):
• R 7 and Rg are independently selected from hydrogen, fluorine, trifluoromethyl, C1-C6 alkyl, and C6-C12 aryl groups;
• R9, Rio, and Rn are independently selected from alkyl and aryl, or taken together with the nitrogen to which they are attached form a cationic center;
• L 6 is a linker that covalently couples the cationic center [N (R 9 )(Rio)(Rn)] to the polymer backbone;
• X " is the counter ion associated with the cationic center
• n is an integer from 5 to about 10,000;
• p is an integer from 5 to about 10,000.
• * represents the point at which the repeating units is covalently linked to either and adjacent repeating unit or a functional group useful for forming hydrogels.
• R 7 and Rs are C1-C3 alkyl.
• R 9 , Rio, and Rn are independently selected from alkyl and aryl, or taken together with the nitrogen to which they are attached form a cationic center. In one embodiment, R 9 , Rio, and Rn are C1-C3 alkyl.
• L 7 is a C1-C20 alkylene chain.
• Representative L 7 groups include -(CH 2 ) n -, where n is 1-20 (e.g., 1, 3, or 5)
• a 3 is C, S, SO, P, or PO.
• n is an integer from 5 to about 5,000.
• crosslinking agent monomers, comonomers, polymers, copolymers, and crosslinks of formulas (I)-(VI) described above.
• PB is the polymer backbone.
• Representative polymer backbones include vinyl backbones (e.g., -C(R)(R")-C(R")(R"")-, where R, R", R", and R" are independently selected from hydrogen, alkyl, and aryl) derived from vinyl monomers (e.g., acrylate, methacrylate, acrylamide, methacrylamide, styrene).
• Other suitable backbones include polymer backbones that provide for pendant groups.
• Other representative polymer backbones include peptide (polypeptide), urethane (polyurethane), and epoxy backbones.
• CH 2 C(R)- is the polymerizable group. It will be appreciated that other polymerizable groups, including those noted above, can be used to provide the monomers and polymers of the invention.
• N + is the cationic center.
• the cationic center is a quaternary ammonium (e.g., N bonded to L 4 , R 5 , 5, and L 5 ).
• other useful cationic centers include imidazolium, triazaolium, pyridinium, morpholinium, oxazolidinium, pyrazinium, pyridazinium, pyrimidinium, piperazinium, and pyrrolidinium.
• R4, R 5 , Re, R 9 , Rio, and Rn are independently selected from hydrogen, alkyl, and aryl groups.
• Representative alkyl groups include CI -CIO straight chain and branched alkyl groups.
• the alkyl group is further substituted with one of more substituents including, for example, an aryl group (e.g., -CH 2 C 6 H 5 , benzyl).
• Representative aryl groups include C6-C12 aryl groups including, for example, phenyl.
• R 5 and R 6 , or R 9 , Rio, and Rn are taken together with N + form the cationic center.
• L 4 (or L 6 ) is a linker that covalently couples the cationic center to the polymer backbone.
• L 4 includes a functional group (e.g., ester or amide) that couples the remainder of L 4 to the polymer backbone (or polymerizable moiety for the monomers).
• L5 can be a C1-C20 alkylene chain.
• Representative L5 groups include -(CH 2 ) n -, where n is 1-20 (e.g., 1, 3, or 5).
• L 7 is a linker that covalently couples the polymer backbone to the anionic group.
• L 7 can be a C1-C20 alkylene chain.
• Representative L 7 groups include -(CH 2 ) n -, where n is 1-20 (e.g., 1, 3, or 5).
• the anionic center can be a carboxylic acid ester (A is C), a sulfuric acid (A is SO), a sulfonic acid (A is SO2), a phosphinic acid (A is P), or a phosphonic acid (A is PO).
• representative alkyl groups include C1-C30 straight chain and branched alkyl groups.
• the alkyl group is further substituted with one of more substituents including, for example, an aryl group (e.g., -CH 2 C 6 H 5 , benzyl).
• aryl groups include C6-C12 aryl groups including, for example, phenyl including substituted phenyl groups (e.g., benzoic acid).
• X " is the counter ion associated with the cationic center.
• the counter ion can be the counter ion that results from the synthesis of the cationic polymers or the monomers (e.g., CI " , Br " , T).
• the counter ion that is initially produced from the synthesis of the cationic center can also be exchanged with other suitable counter ions to provide polymers having controllable hydrolysis properties and other biological properties.
• counter ions also can be chosen from chloride, bromide, iodide, sulfate; nitrate; perchlorate (CIO 4 ); tetrafluoroborate (BF 4 ); hexafluorophosphate (PF 6 ); trifluoromethylsulfonate (S0 3 CF 3 ); and derivatives thereof.
• suitable counter ions include hydrophobic counter ions and counter ions having therapeutic activity (e.g., an antimicrobial agent, such as salicylic acid (2-hydroxybenzoic acid), benzoate, lactate.
• Ri and R 2 is selected from hydrogen, fluoride, trifluoromethyl, and C1-C6 alkyl (e.g., methyl, ethyl, propyl, butyl).
• R ls R 2 , and R4 are hydrogen.
• R ls R 2 , and R 4 are methyl.
• FIGURE 1 is a schematic illustration of the synthesis of a representative star polymer of the invention having zwitterionic (polycarboxybetame) branches.
• the branches are shown terminating with a bromomethyl group, which is the radical initiator group for continued polymerization (e.g., atom transfer radical polymerization, ATRP).
• FIGURE 2 is a schematic illustration of the synthesis of a representative star polymer of the invention having zwitterionic (polycarboxybetame) branches terminated with a thiol group (-CH 2 -SH).
• This star polymer was prepared from the star polymer illustrated in FIGURE 1 by click chemistry (reaction of the star polymer with sodium azide and 3-thioacetylene).
• the functionalized zwitterionic polymer has formula (A):
• (C) is a core (e.g., C1-C50 alkylene, arylene, acrylate, amine, amide, or or other macromolecular cores);
• Ri, R4, R 5 , R8, and M are independently selected from the group consisting of
• K is a cationic center selected from the group consisting of ammonium, imidazolium, triazolium, pyridinium, morpholinium, and other nitrogen-, sulfide-, phosphate-based cations, such as ammoniophosphinates, ammonio(alkoxy)dicyanoethenolates, ammonioboronates, sulfoniocarboxylates, and oxypyridinebetaines;
• R 5 and R 7 are independently selected from the group consisting of hydrogen and
• C1-C6 alkyl or taken together with K form a cationic center selected from the group consisting of ammonium, imidazolium, triazolium, pyridinium, morpholinium, and other nitrogen-, sulfide-, phosphate-based cations, such as ammoniophosphinates, ammonio(alkoxy)dicyanoethenolates, ammonioboronates, sulfoniocarboxylates, and oxypyridinebetaines;
• n is an integer from 5 to about 10,000;
• N c is core multiplicity and is an integer from 1 to 1000;
• Core multiplicity (N c ) is the total number of branches in the polymer. In certain embodiments, the number of branches is from 2 to 500, 3 to 100, 3 to 10, 3 to 6.
• X is a thiol, a disulfide, a maleimide, or one of a click chemistry reactive pair.
• the functionalized zwitterionic polymer has formula (B):
• Q " is a counter ion selected from CI “ , Br “ , ⁇ , S0 4 2” , NO 3 " , C10 4 “ , BF 4 “ , PF 6 “ ,
• imidoester haloacetyl, hydrazide, alkoxyamine, aryl azide, diazirine, maleimide, carbodiimide, N-hydroxysuccinimide (NHS), thiazolidine-2-thione, pyridyldisulfide, difluorinatedcyclooctyne, one of a Staudinger reagent pair, isocyanate, isothiocyanate, thioether, sulfhydryl, hydrazine, hydroxymethyl phosphine, sulfo-NHS ester, pentafluorophenyl ester, sulfonylazide, 5H-dibenz[b,f]azepine, and their derivatives.
• the functionalized zwitterionic polymer has formula (C):
• the functionalized zwitterionic polymer has formula (D):
• R ls R 2 , R3, R 4 , R5, R 6 , R7, Rs, Q, A ls N c , and X are as described above for (A), (B), and (C),
• Mi, M 2 , and M 3 are independently selected and are as described above for M for
• Ki and K 2 are independently selected and are as described above for K for (A),
• P 2 and P3 are as described above for R 2 and R3;
• P 4 , P5, and Pg are as described above for R4, R5, and Rg, respectively;
• P 6 and P 7 are as described above for R 6 and R 7 ;
• Q 4 and Q 5 are as described above for R 4 and R 5 ;
• n is an integer from 5 to about 10,000;
• q is an integer from 5 to about 10,000.
• the functionalized mixed charge copolymer has formula (E):
• N is as described above for M
• R 8 is as described above for R 6 and R 7 .
• R9 is as described above for R 2 and R 3 .
• the functionalized mixed charge copolymer has formula (F):
• the functionalized mixed charge copolymer has formula (G):
• the functionalized mixed charge copolymer has formula (H): wherein
• M 1 ? M 2 , and M 3 are independently M as described above for (G);
• Ni and N 2 are independently N as described above for (G);
• Ki and K 2 are independently K as described above for (G);
• P 2 , P3, and P9 are as for R 2 , R 3 , and R9, respectively;
• P 4 is as for R 4 ;
• P5 and P j o are as for R 5 and R Q, respectively;
• P 6 , P 7 , and P 8 are as for R 6 , R 7 , and R 8 , respectively;
• Q 2 , Q 3 , and Q 4 are as for R 2 , R 3 , and R4, respectively;
• the invention provides hydrogels prepared from the functionalized zwitterionic and mixed charge star polymers.
• Functionalized zwitterionic and mixed charge polymers and copolymers can be used to form homopolymers or copolymers (e.g., hydrogels) by use of the same polymer (e.g., via disulfide linkage of thiol terminated polymers), two or more polymers (e.g. via click chemistry), or with other multifunctional molecules, oligomers, and polymers.
• Poly(carboxybetaine) (pCB) polymers are highly functionalizable due to the presence of abundant carboxylic acid (COOH) groups in the polymer (i.e., present in each constitutional unit). Such functionality renders the polymer versatile for further functionalized with simple chemistries.
• One such chemistry is the coupling of the COOH group with amine functional compounds. This chemistry is simple to carry out due to the high efficiency of coupling agents (e.g., N-(3-dimethylaminopropyl)-N'- ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS)).
• Coupling chemistry can be used to functionalize pCB polymers with a variety of different amines.
• Hydrogel of the invention can be prepared by simply mixing the two polymers with complimentary functional groups.
• a suitable bifunctional crosslinker or other complimentary functionalized compound can be mixed with a reactive pCB polymer to provide a hydrogel.
• first and second zwitterionic polymers e.g., pCBs
• complimentary clickable groups R and R*
• a first polymer bearing pendant first reactive groups (R) and a second polymer bearing pendant second reactive groups (R*) are combined to provide a representative hydrogel of the invention.
• the first and second polymers can be prepared from the same polymer as shown in Scheme 1 (e.g., a zwitterionic polymer or mixed charge copolymer of the invention).
• the hydrogel is formed by crosslinking the first and second polymers through the complimentary first and second reactive groups (e.g., complimentary first and second click groups).
• first and second complimentary reactive (e.g., click- reactive) polymers can be prepared by copolymerization of zwitterionic monomer (e.g., CBMA) and first and second comonomers, respectively.
• the first comonomer includes a first reactive group (e.g., a zwitterionic monomer that further includes the first reactive group, such as a click-reactive group).
• the second comonomer includes a second reactive group (e.g., a zwitterionic monomer that further includes the second reactive group, such as a click-reactive group).
• This copolymerization strategy may be used where a high degree of functionalization is required, such as for preparing a high-strength injectable hydrogel to mimic cartilage or other tissue.
• a high degree of functionalization such as for preparing a high-strength injectable hydrogel to mimic cartilage or other tissue.
• a first zwitterionic copolymer is prepared by copolymerization of a zwitterionic monomer (denoted CB monomer) (e.g., CBMA) and a first comonomer (denoted CB-click monomer) that includes a first reactive group (i.e., a zwitterionic comonomer that further includes the first reactive (e.g., first click-reactive) group).
• a zwitterionic monomer e.g., CBMA
• a first comonomer denoted CB-click monomer
• a second zwitterionic copolymer is prepared by copolymerization of a zwitterionic monomer (denoted CB monomer) (e.g., CBMA) and a second comonomer (denoted CB-click monomer) that includes a second reactive group (e.g., a zwitterionic monomer that further includes the second reactive (e.g., second click- reactive) group, as shown in 2a.
• the hydrogel is formed by crosslinking the first and second polymers through the complimentary first and second reactive groups (e.g., complimentary first and second click reactive groups).
• zwitterionic polymers may be end-group functionalized with complimentary reactive (e.g., click-reactive) groups. See Scheme 3. These end-group functionalized polymers can be used with the polymers and copolymers illustrated in Schemes 1 and 2. The preparation of end-group functionalized polymers and the hydrogel formed by their mixing is shown in Scheme 3.
• a first zwitterionic polymer is end-group functionalized with a first reactive group (e.g., first click-reactive group).
• a second zwitterionic polymer is end-group functionalized with a second reactive group (e.g., second click-reactive group).
• the hydrogel is formed by crosslinking the first and second polymers through the complimentary first and second reactive groups (e.g., complimentary first and second click reactive groups).
• the crosslinking (hydrogel-forming) chemistries above are described as reaction between complimentary reactive groups (i.e., first and second reactive groups).
• the complimentary reactive groups can be any pair of reactive groups having reactivity suitable for bond formation, preferably reactivity suitable for bond formation at temperatures between room and physiological temperature.
• the complimentary reactive groups are click groups (click-reactive pairs), which are well known in the art. Representative zwitterionic click hydrogels formed using the strategies described above are set forth in Examples 1-6.
• the hydrogels can take the form of a scaffold, an injectable hydrogel or nanogel with or without biotic compounds.
• the hydrogels of the present invention further comprise encapsulated small molecules, nanomaterials, nucleic acids, polysaccharides, proteins, and cells.
• Such hydrogels have applications in medical and pharmaceutical sensing, orthopedics, cardiovascular, internal ophthalmic, aesthetic, ocular and drug/protein/drug delivery.
• the hydrogels can be attached to surfaces for medical and engineering applications.
• functionalized zwitterionic polymers can also be attached to biotic or non-biotic molecules and substrates.
• the polymer can be conjugated directly in a degradable or non-degradable way while branches can be replaced by as acrylamide, oxazoline, and vinylpyrrolidone.
• the hydrogels of the invention can be used for objects, devices, and components, such as implantable biosensors; wound care devices, glues and sealants, a contact lens; a dental implant; an orthopedic device such as an artificial joint, an artificial bone, an artificial ligaments, and an artificial tendon; a cardiovascular device such as a cathether, an artificial valve, an artificial vessel, an artificial stent, LVADs, or a rhythm management device; gastroenterology devices such as feeding tubes, alimentary canal clips, gastro-intestinal sleeves, or gastric balloons; OB/Gyn devices such as implantable birth control devices or vaginal slings; nephrology devices such as anastomotic connectors or subdermal ports; neurosurgery devices such as nerve guidance tubes, cerebrospinal fluid drains or shunts, dermatology devices such as skin repair devices an ophthalmic device such as a shunt, otorhinolaryngology devices such as stents, cochlear implants, tubes, s
• hydrogels of the invention are functionalized zwitterionic polymers-based hydrogel for islets encapsulation.
• Functionalized star-shaped poly(carboxybetaine) polymers (pCB) prepared by polymerization of CBMA were synthesized via a combination of ATRP and click chemistry.
• Thiol group-terminated pCB polymers was synthesized, and pCB hydrogels were formed by mixing thiol-terminated pCBs with 1 ,2-bis(maleimido)ethane together under physiological conditions.
• the molecular weight of the polymer can be tuned by the stoichiometric ratio between the monomer and the initiator.
• Star polymers with molecular weights of 5000, 20,000 and 50,000 were synthesized.
• Other living polymerization methods, such as RAFT, can also be applied to synthesize the polymer.
• the functionalized star pCB polymers were prepared by click chemistry. As shown in FIGURE 2, after purification, the terminal bromine groups of the initially formed star pCB were transformed into azido groups by a nucleophilic substitution reaction with sodium azide in water. The product was purified by dialysis. Lyophilization was used to remove the water.
• pCB-N 3 (pCB-azide) chains were then reacted with the alkyne-SH in methanol with CuBr/PMDETA as catalyst to produce the star pCB polymers with four arm.
• thiol-terminated star pCB was obtained after purification via dialysis and lyophilization.
• FIGURES 3A and 3B schematically illustrate the preparation of a representative hydrogel of the invention prepared from suitably functionalized star polymers of the invention.
• FIGURE 3A illustrates the syntheses of two representative star polymers of the invention: (a) a star polymer having zwitterionic (polycarboxybetaine) branches terminated with a thiol group (-CH 2 -SH) denoted pCB-A; and (b) a star polymer having zwitterionic (polycarboxybetaine) branches terminated with a pyridyl disulfide group (-CH 2 -S-S-C 5 H 4 N) denoted pCB-B.
• FIGURE 3B illustrates the preparation of representative hydrogels of the invention prepared from reaction of the star polymers (pCB-A and pCB-B) illustrated in FIGURE 3A.
• the hydrogels can be formed by simply mixing pCB-A with pCB-B in the presence of cells.
• Glucose consumption in culture media was used to measure the metabolic activity of hydrogel-encapsulated islets maintained in culture. Glucose metabolism was measured primarily by the glucose utilization in medium by the cultured islets and shown as an indicator not only for islet viability, but also cellular activity. The uptake of glucose in medium was measured every 48 h over the 18 day period to assess islet quality. Glucose uptake in encapsulated islets was maintained near 100% of the day 1 level until day 18 (FIGURE 4B). In control islets, glucose consumption decreased to 72% by day 7, and further declined as time progressed. By day 14 and 18, only 59% and 38% of the glucose was utilized, respectively.
• encapsulated islets maintained much higher metabolic activity as compared to control islets (p ⁇ 0.01).
• cultured islets were incubated in either low (3 mM) or high(17 mM) glucose medium for 18 h on day 0 and day 18 (FIGURE 4B).
• the glucose responsiveness was not preserved in the control cultured islets tested on day 18 (p ⁇ 0.05, vs. control on day 0 and encapsulated islets on day 18).
• the decreased insulin storage/secretion ability of the control islets was also shown by decreased insulin staining by dithizone (DTZ) on day 18 (FIGURE 4C).
• DTZ dithizone
• FIG. 4C To further assess beta cell function, dynamic glucose stimulated insulin release was tested in a perifusion system using islets that were cultured with or without hydrogel encapsulation for 18 days. Although the same number of islets was present in both the encapsulated and control samples on day 0, islets in the control group disintegrated over time and did not show stimulated insulin secretion. In contrast, encapsulated islets responded well to glucose stimulation (FIGURE 4D).
• Hydrogels can also be formed by mixing two different polymers. For example, as presented in FIGURE 3A, thiol-terminated pCB-A and pyridyldisulfide-terminated pCB-B were synthesized via a combination of ATRP and click chemistry.
• the hydrogel can be formed by mixing pCB-A with pCB-B under physiological conditions (see FIGURE 3B). Because the hydrogel can be formed under physiological conditions, cells such as stem cells, immune cells, neural cells, hormone-secreting cells, and heart cells can be added in the process of gelation in order to be encapsulated within the hydrogels. In addition, due to the hydrogel is being crosslinked with disulfide bonds, the hydrogel can be degraded by biological agents such as cysteine.
• PBSC peripheral blood stem cell
• FIGURES 5A and 5B present data for encapsulated peripheral blood stem cell (PBSC) cells cultured in a representative hydrogel (pCB hydrogel) of the invention.
• FIGURE 5A illustrates hydrogel modulus over time (hydrogel degradation).
• FIGURE 5B is an image showing the results of a LIVE/DEAD assay performed on encapsulated PBSC cells within the pCB hydrogels after 7-day in vitro culture.
• hydrogels of the invention can further include components or additives that are advantageously administered by the methods of the invention.
• the hydrogel further includes cells.
• the cells are contained within or encapsulated in the hydrogel.
• the nature of the cell encapsulated in the hydrogel is not limited (natural cells and genetically modified cells, as well as triturates thereof).
• Representative cells that are advantageously encapsulated in the hydrogel include exocrine secretory epithelial cells, hormone secreting cells, keratinizing epithelial cells, wet stratified barrier epithelial cells, sensory transducer cells, autonomic neuron cells, sense organ and peripheral neuron supporting cells, neurons and glial cells, lens cells, hepatocytes, adipocytes, lipocytes, barrier function cells, kidney cells, heart cells, extracellular matrix cells, contractile cells, blood and immune system cells such as erythrocytes, monocytes, neutrophils, mast cells, T cells, stem cells, germ cells, nurse cells, interstitial cells, progenitor cells, and hematopoietic stem cells.
• the hydrogel further includes viruses.
• the viruses are contained within or encapsulated in the hydrogel.
• Representative viruses include retroviruses and adenoviruses.
• the hydrogel further includes bacteria.
• the bacteria are contained within or encapsulated in the hydrogel. Representative bacteria include clostridial species, S. typhimurium, and E. coli.
• Other materials advantageously encapsulated in the hydrogels include proteins, peptides, nucleic acids (oligonucleotides), polysaccharides, small molecules (i.e., organic, inorganic and organometallic compounds having a molecular weight less than about 800 g/mole) and nanomaterials.
• Representative proteins include antibodies, antibody fragments, enzymes (e.g., therapeutic and protective enzymes), and peptides.
• Representative nucleic acids include DNAs (e.g., cDNA) and RNAs (e.g., siRNA, mRNA)
• Representative small molecules include thereapuetic agents and diagnostic agents (e.g., fluorescent and magnetic resonance imaging agetns).
• Representative nanomaterials include carbon nanostructures (e.g., carbon nanotubes and graphenes) and quantum dots.
• hydrogels Other materials advantageously encapsulated in the hydrogels include lipoplexes, polymerosomes, polyplexes, dendrimers, and inorganic particles.
• the hydrogel is crosslinked with a degradable crosslinker.
• degradable crosslinkers include peptides, polysacharrides, anhydride crosslinkers, dissulfide crosslinkers, and polyester crosslinkers.
• the hydrogel can be designed to degrade under specific circumstances (e.g., physiological conditions), such as by hydrolysis or digestion by by enzymes.
• the hydrogel of the invention is prepare from functionalized zwitterionic polymers and has formula (J):
• (CI) and (C2) are cores and are independently selected from acrylate functionalized C1-C6 alkyl, and C6-C12 aryl groups; amine functionalized C1-C6 alkyl, and C6-C12 aryl groups; amide functionalized C1-C6 alkyl, and C6-C12 aryl groups; epoxy functionalized C1-C6 alkyl, and C6-C12 aryl groups; C1-C6 alkyl, and C6-C12 aryl groups; or other macromolecular core;
• Rj-Rg are as described above for (A);
• R9-R16 are as f° r R-i ⁇ R-8' respectively,
• N is M
• Ki and K 2 are independently as described above for K for (A);
• a 2 is C, SO, S0 2 , P, or PO " ;
• n is an integer from 5 to about 10,000;
• n is an integer from 5 to about 10,000;
• Nci and N c2 are core multiplicities and are integers independently selected from 2 to 1000;
• q is the an integer intermediate N cl and N c2 .
• the hydrogel of the invention is prepare from functionalized zwitterionic polymers and has formula (K): R: 8 R 16
• the hydrogel of the invention is prepare from functionalized mixed charge copolymers and has formula (L):
• (CI) and (C2) are cores and are independently selected from acrylate functionalized C1-C6 alkyl, and C6-C12 aryl groups; amine functionalized C1-C6 alkyl, and C6-C12 aryl groups; amide functionalized C1-C6 alkyl, and C6-C12 aryl groups; epoxy functionalized C1-C6 alkyl, and C6-C12 aryl groups; C1-C6 alkyl, and C6-C12 aryl groups; or other macromolecular core;
• R 1 1 -R 2 o are as for counterpart R j -R ⁇ ;
• Mi and M 2 are independently as described above for M for (K);
• Ni and N 2 are independently as described above for N for (K);
• Ki and K 2 are independently as described above for K for (K);
• a 2 is C, SO, S0 2 , P, or PO " ;
• n is an integer from 5 to about 10,000;
• n is an integer from 5 to about 10,000;
• Nci and N c2 are core multiplicities and are integers independently selected from 2 to 1000;
• q is the an integer intermediate N cl and N c2 .
• the hydrogel of the invention is prepare from functionalized mixed charge copolymers and has formula (M):
• R 21 and R 22 are functional groups and are independently selected from the groups defined by Rg for (F).
• the invention provides surfaces that have been treated with the zwitterionic or mixed charge hydrogels of the invention.
• the hydrogels of the invention which in certain embodiments are hydrolyzable to zwitterionic polymers or mixed charge copolymers, can be advantageously used as coatings for the surfaces of a variety of devices including, for example, medical devices.
• the hydrogels of the invention are advantageously used to coat surfaces to provide biocompatible, antimicrobial, and nonfouling surfaces. Accordingly, in another aspect, the invention provides devices and materials having a surface (i.e., one or more surfaces) to which have been applied (e.g., coated, covalently coupled, ionically associated, hydrophobically associated) one or more crosslinked zwitterionic hydrogels of the invention.
• Representative devices and carriers that may be advantageously treated with a hydrogel of the invention, modified to include a hydrogel of the invention, or incorporates a hydrogel of the invention include:
• particle e.g., nanoparticle having a surface treated with, modified to include, or incorporates a hydrogel of the invention
• drug carrier having a surface treated with, modified to include, or incorporates a material of the invention
• non- viral gene delivery system having a surface treated with, modified to include, or incorporates a hydrogel of the invention
• biosensor having a surface treated with, modified to include, or incorporates a hydrogel of the invention
• devices for bioprocesses or bioseparations such as membranes for microbial suspension, hormone separation, protein fractionation, cell separation, waste water treatment, oligosaccharide bioreactors, protein ultrafiltration, and diary processing having a surface treated with, modified to include, or incorporates a hydrogel of the invention; implantable sensor having a surface treated with, modified to include, or incorporates a hydrogel of the invention;
• subcutaneous sensor having a surface treated with, modified to include, or incorporates by a hydrogel of the invention
• implant such as a breast implant, cochlear implant, and dental implant having a surface treated with, modified to include, or incorporates a hydrogel of the invention; contact lens having a surface treated with, modified to include, or incorporates a hydrogel of the invention;
• tissue scaffold having a surface treated with, modified to include, or incorporates a hydrogel of the invention
• implantable medical devices such as an artificial joint, artificial heart valve, artificial blood vessel, pacemaker, left ventricular assist device (LVAD), artery graft, and stent having a surface treated with, modified to include, or incorporates a hydrogel of the invention
• an ear drainage tube such as an ear drainage tube, feeding tube, glaucoma drainage tube, hydrocephalous shunt, keratoprosthesis, nerve guidance tube, urinary catheter, tissue adhesive, and x-ray guide having a surface treated with, modified to include, or incorporates by a hydrogel of the invention.
• Suitable substrates and surfaces that may be advantageously treated with a hydrogel of the invention, modified to include a hydrogel of the invention, or incorporates a hydrogel of the invention include fabrics and such as in clothing (e.g., coats, shirts, pants, undergarments, including such as worn by hospital and military personnel), bedding (e.g., blankets, sheets, pillow cases, mattresses, and pillows), toweling, and wipes.
• clothing e.g., coats, shirts, pants, undergarments, including such as worn by hospital and military personnel
• bedding e.g., blankets, sheets, pillow cases, mattresses, and pillows
• toweling e.g., towels, and wipes.
• the hydrogels of the invention can be coated onto a variety of surfaces including surfaces of objects, devices, and components such as implantable biosensors; wound care devices, glues and selants, a contact lens; a dental implant; an orthopedic device such as an artificial joint, an artificial bone, an artificial ligaments, and an artificial tendon; a cardiovascular device such as a cathether, an artificial valve, an artificial vessel, an artificial stent, LVADs, orand a rhythm management device; gastroenterology devices such as feeding tubes, alimentary canal clips, gastro-intestinal sleeves, or gastric balloons; OB/Gyn devices such as implantable birth control devices or vaginal slings; nephrology devices such as anastomotic connectors or subdermal ports; neurosurgery devices such as nerve guidance tubes, cerebrospinal fluid drains or shunts, dermatology devices such as skin repair devices an ophthalmic device such as a shunt, otorhinolaryngology devices such as stents, co
• the invention provides a method for making a zwitterionic or mixed charge polymeric hydrogel.
• the method is an in situ method, such as an in vivo method, in which a suitably functionalized zwitterionic star polymer or a suitably functionalized mixed charge star copolymer is introduced to an environment where the hydrogel is desirably located.
• a suitably functionalized zwitterionic star polymer or a suitably functionalized mixed charge star copolymer is introduced to an environment where the hydrogel is desirably located.
• the functionalized zwitterionic star polymer or a functionalized mixed charge star copolymer can be introduced to the desired site by, for example, injection.
• the hydrogel and its added cargo can be advantageously formed at desired in vivo sites.
• two suitable functionalized zwitterionic polymers of the invention are administered such that the two polymers react to form a hydrogel when combined or come into contact with each other in situ (e.g., in vivo after injection at the desired site).
• two functionalized mixed charged copolymers of the invention are administered such that the two polymers react to form a hydrogel when combined or come into contact with each other in situ (e.g., in vivo after injection at the desired site).
• the invention provides zwitterionic and mixed charge polymers and copolymers having therapeutic agents covalently coupled thereto. These conjugates are useful for therapeutic agent delivery. Controlled release of therapeutic agents from the polymers of the invention by hydrolysis The following is a description of a representative conjugate of the invention and release of therapeutic agent from the conjugate.
• FIGURE 6 is a schematic illustration of the release of a representative therapeutic agent from a representative star polymer of the invention having zwitterionic (polycarboxybetaine) branches.
• the branches are further extended by extension polymerization with CBMA to provide branches having constitutional units that are zwitterionic in addition to constitutional units bearing the therapeutic agent.
• the star polymer illustrated in FIGURE 6 is a block copolymer.
• the star polymer is a random copolymer prepared by copolymerization of zwitterionic monomers (e.g., CBMA) and zwitterionic- therapeutic agent monomers (e.g., CBMA-therapeutic agent).
• zwitterionic monomers e.g., CBMA
• CBMA-therapeutic agent e.g., CBMA-therapeutic agent
• the therapeutic agent is released. Hydrolysis of the star polymer and release of the therapeutic agent regenerates a zwitterionic constitutional unit in the star polymer.
• the therapeutic agent is ibuprophen
• the monomer for synthesizing the star polymer capable of releasing ibuprophen is prepared by condensation of CBMA with ibuprophen.
• ibuprofen was incorporated into carboxybetaine methacrylate (CBMA) via anhydride formation reaction by stirring with dicyclohexylcarbodiimide (DCC) in dichloromethane (DCM) to provide a polymerizable monomer.
• DCC dicyclohexylcarbodiimide
• DCM dichloromethane
• a 4-arm star zwitterionic polymer was prepared from the monomer to provide a polymer therapeutic agent conjugate.
• the therapeutic agent is released by hydrolysis.
• the resulting polymer after the hydrolysis is converted to its counterpart zwitterionic polymer.
• the term "about” has the meaning reasonably ascribed to it by a person skilled in the art when used in conjunction with a stated numerical value or range (i.e., denoting somewhat more or somewhat less than the stated value or range, to within a range of ⁇ 20% of the stated value; ⁇ 19% of the stated value; ⁇ 18% of the stated value; ⁇ 17% of the stated value; ⁇ 16% of the stated value; ⁇ 15% of the stated value; ⁇ 14% of the stated value; ⁇ 13% of the stated value; ⁇ 12% of the stated value; ⁇ 11% of the stated value; ⁇ 10% of the stated value; ⁇ 9% of the stated value; ⁇ 8% of the stated value; ⁇ 7% of the stated value; ⁇ 6% of the stated value; ⁇ 5% of the stated value; ⁇ 4% of the stated value; ⁇ 3% of the stated value; ⁇ 2% of the stated value; or ⁇ 1% of the stated value).
• a representative hydrogel of the invention is prepared from first and second zwitterionic polymers.
• the first polymer includes pendant first reactive groups (i.e., cyclooctyne) and the second polymer includes pendant second reactive groups (i.e., azide).
• the polycarboxybetaine (pCB) polymer is functionalized in two different reactions with a cyclooctyne amine and an azido amine, respectively, using the known EDC/NHS coupling.
• the pCB polymers are first activated by EDC/NHS chemistry and then the polymer is purified by precipitation in THF. The activated polymer is then treated with respective amines. The polymer is again purified by precipitation in THF. The purified polymer is dried under vacuum.
• the degree of functionalization is characterized by 1H and 13 C NMR.
• the representative functionalized copolymer includes pendant groups (i.e., N-hydroxysuccinimide groups) that allow for covalent coupling of further activating groups (complimentary reactive groups) to provide crosslinkable polymers useful for forming hydrogels of the invention.
• Carboxybetaine methacrylate monomer (CBMA) is functionalized with N-hydroxysuccinimide (NHS-CBMA). This monomer is copolymerized with carboxybetaine methacrylate monomer (CBMA) (see Scheme 3). The resultant polymer is a random polymer of CBMA and NHS-CBMA. The copolymerization is shown below.
• the feed ratio of the two monomers can be varied to provide functionalized polymers having different degrees of functionalization.
• the activated polymer can be readily further functionalized with suitable amines, facilitating steps la and lb in Scheme 1.
• a representative hydrogel of the invention is prepared from first and second zwitterionic polymers.
• the first polymer includes pendant first reactive groups (i.e., thiol) and the second polymer includes pendant second reactive groups (i.e., maleimide).
• first and second polycarboxybetaine polymers are shown below.
• a functionalized carboxybetaine monomer is synthesized first with complimentary clickable groups.
• This functionalized monomer is random polymerized with CBMA monomer.
• maleimide and thiol functionalized CBMA monomers are synthesized using amines based on maleimide and thiol.
• the polymer is purified by precipitation in THF to remove unreacted monomers.
• the composition of the polymer is confirmed by NMR ( ⁇ H and 13 C).
• the amount of functionalized units in the polymer is varied by adjusting the feed ratios.
• complimentary clickable polymers are synthesized. These polymers are mixed at 5-10 wt% in water to form the hydrogel.
• a modified carboxybetaine monomer is synthesized by modification of the ammonium moiety retaining the negative charge on the carboxylate to provide a thiol-functionalized zwitterionic monomer.
• Copolymerization of the CBMA and the modified CBMA monomers to provide a functionalized zwitterionic copolymer is shown below.
• Functionalized star-shaped pCB polymers were synthesized via a combination of ATRP and 'Click' reaction. Maleimide and thiol group-terminated pCB polymers with different molecular weights were synthesized.
• pCB hydrogels were formed by mixing maleimide-terminated pCB (pCB-A) with thiol-terminated pCB (pCB-B) together under physiological conditions.
• the mechanical properties, equilibrium water content (EWC) and pore sizes of the hydrogel can be tuned by adjusting the molecular weight of the polymers and the amount of used polymers.
• the molecular weight of the polymer can be tuned by the stoichiometric ratio between the monomer and the initiator.
• Star polymers with weight average molecular weights of 5000, 20000 and 50000 were synthesized.
• Other living polymerization method such as reversible addition-fragmentation chain-transfer (RAFT) can also be applied to synthesize the polymer.
• RAFT reversible addition-fragmentation chain-transfer
• pCB gels were formed by adding pCB-A with various polymer weight percentage solutions of pCB-B in PBS at 37 °C. See, e.g., FIGURE 3.
• the hydrogels obtained were washed thoroughly with distilled water to remove the unreacted polymers.
• the EWCs of the hydrogels were measured at 37 °C using a gravimetric method. The temperature was controlled by a thermostatic water bath with a precision of ⁇ 0.1 °C.
• the samples were immersed in 0.1 M PBS buffer solutions (pH 7.4) for at least 24 h and then taken out, blotted with wet filter paper to remove water on the surface, and weighed on a microbalance. After crosslinking, hydrogels were allowed to freely swell in PBS for 24 hours.
• Islet viability assessment The viability of porcine islets was quantitatively monitored by luminescence intensity. Hydrogel-encapsulated islets or control islets isolated from pigs (100 islets/well) were cultured for up to 28 days and luminescence intensity was measured using the Xenogen image system (Caliper Life Sciences, Hopkinton, MA) by adding 0.75 mg/mL D-luciferin to the islet culture medium. Islet viability was also qualitatively assessed using Live/Dead staining at desired time points. Live/Dead staining was done by incubating cell-laden hydrogels in PBS containing 0.24 mM fluorescein diacetate and 7.5 mM propidium iodide for 10 min. Hydrogels were then rinsed in PBS and imaged by fluorescence microscopy (Olympus 1X50, Olympus America, Central Valley, PA).
• Islets cultured with or without hydrogel as described above were hand-picked after 14 days in culture and collected in micro-tubes (single islet/tube, sexplicate), washed with RPMI 1640 medium containing 3 mM glucose (low-glucose media) supplemented with 5% FBS 3 times.
• Islets were cultured in a non-tissue culture coated 96 well plate with either low-glucose or high-glucose (17 mM glucose) media for 16 h at which time concentrations of insulin and C-peptide in supernatant media were measured using Porcine Insulin and Porcine C-peptide Elisa kits (Mercodia, Winston Salem, NC) according to the manufacturer's instructions.
• Islets Short-term response to glucose stimulated insulin release by perifusion assay. Islets were cultured with or without hydrogel as previously described (200 islets/sample on day 0). On day 28, islets were collected and sandwiched-trapped between a bi-layer of microbeads (Biorad, Hercules, CA) in a minicolumn and perifused at 37°C with Krebse Ringer's buffer for 45 min, followed by a low-glucose buffer (3 mM glucose) for 10 min, a high-glucose (17 mM glucose) buffer for 15 min, and finally a low-glucose buffer. Effluents were collected every 2 min starting from the first 3 mM medium. The medium samples or effluents collected in the experiment was analyzed for insulin concentration using an Enzyme -Linked Immunosorbent Assay (ELISA) kit (Mercodia, Winston Salem, NC) for porcine insulin following the manufacturer's protocol.
• ELISA Enzyme -Linked Immun
• Functionalized star-shaped pCB polymers were synthesized via a combination of ATRP, '"click” reaction, and conjugation. The synthesis is illustrated schematically in FIGURE 7.
• Difluorinated cyclooctyne moiety (DIF03)-terminated pCB polymers with different molecular weights were synthesized.
• pCB hydrogels were formed by mixing difluorinated cyclooctyne moiety-terminated pCB (pCB-A) with biodegradable azide- GG-(KE) 2 o-GPQGIWGQ-(KE) 2 o-GG-azide together under physiological conditions.
• the mechanical properties, equilibrium water content (EWC), and pore sizes of the hydrogel can be tuned by adjusting the molecular weight of the polymers and the amount of used polymers.
• the molecular weight of the polymer can be tuned by the stoichiometric ratio between the monomer and the initiator.
• Star polymers with weight average molecular weights of 5000, 20000 and 50000 were synthesized.
• Other living polymerization method such as reversible addition-fragmentation chain-transfer (RAFT) can also be applied to synthesize the polymer.
• RAFT reversible addition-fragmentation chain-transfer
• pCB gels were formed by adding DIF03 -terminated pCB with various polymer weight percentage solutions of aforementioned peptide in PBS at 37 °C.
• the hydrogels obtained were washed thoroughly with distilled water to remove the unreacted polymers.
• the EWCs of the hydrogels were measured at 37 °C using a gravimetric method. The temperature was controlled by a thermostatic water bath with a precision of ⁇ 0.1 °C.
• the samples were immersed in 0.1 M PBS buffer solutions (pH 7.4) for at least 24 h and then taken out, blotted with wet filter paper to remove water on the surface, and weighed on a microbalance. After crosslinking, hydrogels were allowed to freely swell in PBS for 24 hours.

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