CN111714690A - Hydrogel material for treating full-thickness burn wound and preparation method thereof - Google Patents

Abstract

The invention provides a hydrogel material for treating a full-thickness burn wound surface, which is an ABA type triblock reticular copolymer formed by polymerizing a polyethylene glycol monomer and an N-isopropyl acrylamide monomer, wherein the mass ratio of the polyethylene glycol monomer to the N-isopropyl acrylamide monomer is 1: 3-4, the copolymer comprises a mussel bionic tissue adhesive group and a silver nanoparticle anchoring group, silver nanoparticles are loaded on the hydrogel, and cyclosporine A is loaded on the surface and inside of the hydrogel. The hydrogel material prepared by the invention has the characteristics of high strain, biocompatibility, adhesiveness, heat sensitivity, injectability, antimicrobial property and the like. In particular, it can effectively promote the healing speed of the full-thickness burn wound.

Description

Hydrogel material for treating full-thickness burn wound and preparation method thereof

Technical Field

The invention belongs to the technical field of hydrogel materials, and particularly relates to a hydrogel material for treating a full-thickness burn wound and a preparation method thereof.

Background

Burn is a kind of tissue damage caused by various heat sources including hot liquid, high temperature gas, flame, hot metal, chemical substances, etc., and mainly occurs in superficial body tissues such as skin and mucosa. After a severe burn has occurred, in addition to regional local damage to the skin mucosa, the following reactions occur: increased metabolism, decreased body temperature, excessive loss of water, massive loss of proteins, and disturbances of the endocrine and immune systems. The exposed burn wound can cause body fluid balance disorder and defense barrier damage in a short time, and the wound which is not healed for a long time can also become a hotbed for bacteria to colonize and grow. Therefore, after the burn occurs, particularly in large-area burn, the dressing is used for covering the wound surface and is temporarily used as a body surface protection barrier to prevent further invasion of bacteria and promote the wound surface to heal, which is very important.

At present, the traditional medical dressing which is clinically used for burn wounds is mainly gauze and cotton pads, has water absorption and certain air permeability, and is simple in manufacturing process, low in price and reusable. However, the traditional dressing has poor moisturizing effect, does not have antibacterial capability, and can shift and fall off; when the wound dressing is replaced, the gauze is dried and knotted, and granulation tissues are adhered to the wound surface, so that secondary injuries such as pain, bleeding and the like of a patient are caused. How to promote the regeneration and repair of deep local tissues of burn wounds through medical dressings gradually draws attention of clinicians. It has been found that suitable tissue regeneration conditions include certain humidity, temperature and sterility conditions. Therefore, the ideal dressing should have the characteristics of absorbing wound seepage, maintaining the humidity and temperature of the wound, having certain air permeability and antibacterial capability and the like, thereby promoting the healing of the wound.

Synthetic materials have long been found to help promote healing of skin wounds. In 1962, the international paper published by the Winter doctor of university in london in Nature journal, which demonstrates the healing effect of moist environment on wound surface: compared with the sealing of the porcine fault skin defect wound with a polyethylene film, the re-epithelialization probability of the wound exposed to air is increased by 50% (Nature.1962; 193: 293-4). Pulat et al (Polymer edition.2013; 24(7):807-819) synthesizes a novel wound dressing-semipermeable network hydrogel by using ethylene glycol dimethacrylate as a cross-linking agent and polyacrylamide and chitosan as raw materials, so as to realize the burst release of antibiotics and the controlled release of growth factors. The water content of the gel is very high (about 80%), and the swelling property is stable in the pH range (pH4.0-7.0) of the wound matrix; the material is loaded with antibiotic piperacillin-tazobactam, and the growth factor is EGF; when the dressing is applied to the wound surface for 1h, the concentration of the piperacillin-tazobactam in the serum can reach the treatment amount, and the EGF can be continuously released for 5 days. Choi et al (Journal of biological materials research, 2010; 95(2):564-573) prepared a wound-surface-adhesive temperature-sensitive hydrogel for diabetic ulcer, blending glycidyl methacrylate esterified chitosan oligosaccharide, diacryloyl pluronic and rhEGF to prepare a physically crosslinked hydrogel, and irradiating by light to prepare a chemically crosslinked gel; applying 80 mu L of physical cross-linked gel (containing 1 mu g of rhEGF) in a solution state on the burn wound surface of the back of the mouse, irradiating for 30s to enable the physical cross-linked gel to generate chemical cross-linking, and then covering with a medical bandage; research results show that the rhEGF-encapsulated hydrogel can improve the local rhEGF concentration of the wound surface and maintain the differentiation of keratin cells, thereby promoting the healing of the wound surface difficult to heal. In the above series of studies, hydrogel was one of the main active ingredients. As a high molecular polymer, the performance of the hydrogel is superior to that of the traditional dressing and biological dressing, the hydrophilic group enables the hydrogel to have strong water absorption capacity, after water absorption, the hydrogel expands, is firmly combined with water molecules and is stored, and the hydrogel can absorb wound seepage and has certain moisture retention capacity. The three-dimensional network structure formed by the hydrogel macromolecules through crosslinking enables the hydrogel macromolecules to be a carrier of certain specific medicines besides the inherent characteristics of the hydrogel macromolecules, and the hydrogel macromolecules can play the functions of the medicines. On the other hand, various researches show that the organic components of the hydrogel have the capability of improving the microenvironment of the wound surface and can effectively promote the healing of the wound surface.

However, hydrogels also have a number of deficiencies. For example, after the hydrogel is placed on a wound surface, the movement of body muscles easily causes the damage and even the rupture of the gel, thereby increasing the infection risk, and simultaneously destroying the hydrogel structure and affecting the function. In addition, the hydrogel itself is not antimicrobial and does not resist the invasion of bacteria, thus presenting the risk of infection. After the hydrogel is used for a long time, the hydrogel swells due to strong water absorption capacity and is poorly attached to a wound surface. In addition, the ideal hydrogel agent applied to burn wounds needs to meet higher requirements: the damage of the dressing is automatically repaired, and the dressing has the strain; the drug is carried partially, so that the wound surface infection is prevented, and the antibacterial property is achieved; the state can be changed, and the long-time laminating property is realized; releasing certain medicine for promoting wound healing; however, no hydrogel capable of achieving the above characteristics is available in clinic.

Therefore, whether a hydrogel material can be produced or not can be carried with partial medicines on the basis of ensuring the water absorption and moisture retention, so that the hydrogel material can prevent wound infection and has antibacterial property; the state of the adhesive tape can be changed, and the adhesive tape has long-time adhesion; meanwhile, certain medicine for promoting wound healing can be released, so that the medicine can be used for treating the full-thickness burn wound efficiently; becomes a technical problem worthy of research.

Disclosure of Invention

The present invention aims to solve the technical problems, and provides a hydrogel material for treating a full-thickness burn wound and a preparation method thereof. The hydrogel material provided by the invention is used for treating a full-thickness burn wound surface, so that the burn wound surface can be quickly healed, and the hydrogel material has biological tissue adhesiveness, temperature sensitivity and antibacterial property.

The hydrogel material is an ABA type triblock reticular copolymer formed by polymerizing polyethylene glycol monomers and N-isopropylacrylamide monomers, the mass ratio of the polyethylene glycol monomers to the N-isopropylacrylamide monomers is 1: 3-4, the copolymer comprises mussel bionic tissue adhesive groups and silver nanoparticle anchoring groups, silver nanoparticles are loaded on the hydrogel, and cyclosporine A is loaded on the surface and inside of the hydrogel.

Wherein, the mussel bionic tissue adhesive group is dopamine group, and the silver nanoparticle anchoring group is sulfhydryl group. The number average molecular weight of the polyethylene glycol is 8000-.

The hydrogel material obtained by the invention strictly controls the mass ratio of the polymerized monomers, and simultaneously carries nano silver and cyclosporine A, and the hydrogel material obtained by the invention is found to show excellent capability of promoting the rapid healing of the whole burn wound. And the molecular weight of the polyethylene glycol is selected, the length and the structure of the obtained reticular copolymer are accurately controlled, and the effect of the reticular copolymer on healing of the full-thickness burn wound can be better exerted.

The structure of the hydrogel material provided by the invention has the following characteristics:

1) the hydrogel material contains temperature-sensitive response groups, can endow hydrogel with good temperature response performance, is in a liquid state at normal temperature or below body temperature, is converted into a gel state at body temperature or when contacting body surfaces, is convenient for storage and transportation, and is beneficial to surgical use such as spraying or injection;

2) mussel bionic tissue adhesive group (dopamine group) has been proved to endow the prepared adhesive with good adhesion to biological tissues, and the introduction of the group can ensure good adhesion of hydrogel to burned tissues in the using process;

3) the introduction of the silver nanoparticle anchoring group (sulfydryl) can enable organic dynamic bond combination between the hydrogel and the silver nanoparticles, and further improve the strength of the silver nanoparticle composite hydrogel. Under the low temperature condition, the hydrogel, the silver nanoparticles and the CsA are prepared into aqueous solution with proper concentration according to the requirements of experimental conditions, the aqueous solution can be sprayed or injected to burn wounds, and a hydrogel protective layer is formed through the temperature change of the wounds.

The molecular structural formula of the triblock reticular copolymer provided by the invention is shown as a formula (I):

wherein x, y and z are integers from 1 to n.

After the hydrogel material provided by the invention is loaded with CsA and silver nanoparticles with antibacterial effect, the burn wound can be always under the antibacterial and CsA administration effects through the slow release effect. In addition, because the hydrogel has catechol hydrogen bonds, pi-pi interaction force and dynamic hydrosulfur-silver bonds, the hydrogel material has good self-repairing performance, and the performance can ensure that the wound can be self-repaired when damaged by external force to avoid the injury caused by the exposure of the wound.

The hydrogel prepared by the invention has the characteristics of high strain, biocompatibility, adhesiveness, heat sensitivity, injectability, antimicrobial property and the like. The hydrogel can realize effective sol-gel transformation at low temperature or room temperature, the performance endows the material with good injectability and postoperative cleaning convenience, and simultaneously, as the main component in the hydrogel is high molecular material polyethylene oxide (PEG) with good biocompatibility, the hydrogel material has excellent biocompatibility to cells.

The hydrogel prepared by the invention has good self-repairing performance, has excellent antibacterial effect on common E-coli bacteria, is obviously anti-sticking and self-cleaning to skin cells, is convenient to use due to the temperature responsiveness, and can be injected. The mechanical strength of the hydrogel material can be adjusted by changing the content of dopamine and the proportion of other components in the mussel bionic polymer material.

The hydrogel material provided by the invention has an obvious healing promoting effect on burn wounds, wherein the local release of CsA is beneficial to promoting the healing of the burn wounds and reducing the local inflammatory reaction intensity of burns. Research shows that the hydrogel material of the invention can promote the healing speed of the full-thickness burn wound, reduce the release of inflammatory factors in vivo, promote the growth of granulation tissues and the like.

Another object of the present invention is to provide a preparation method of the hydrogel material for treating a full-thickness burn wound, the preparation method comprising the following steps:

(1) firstly, synthesizing a copolymer from an N-isopropyl acrylamide monomer and a polyethylene glycol monomer by using a RAFT (reversible addition-fragmentation chain transfer) polymerization method;

(2) then, replacing the active ester in the copolymer obtained in the step (1) with a mussel bionic tissue adhesive group, and introducing the mussel bionic tissue adhesive group into the polymer;

(3) adding mercaptoethylamine into the product obtained in the step (2) to carry out chemical grafting reaction;

(4) and (4) loading the substance obtained in the step (3) with cyclosporine A and silver nanoparticles to obtain the hydrogel material.

Compared with the prior art, the invention has the following beneficial effects:

the hydrogel material prepared by the invention has temperature sensitivity, self-repairing capability, antimicrobial property and antifouling property, and particularly can efficiently promote the rapid healing of burn wound surfaces. The silver nanoparticles loaded with the CsA and having the antibacterial effect can enable burn wounds to be always under the antibacterial and CsA administration effects through slow release, and can have good self-repairing performance, so that the wounds can be guaranteed to be self-repaired due to external force damage to avoid injury caused by exposure of the wounds. Meanwhile, the hydrogel material can also reduce the release of inflammatory factors in vivo, promote the growth of granulation tissues and the like.

Drawings

FIG. 1 is a schematic structural view of a hydrogel of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the following embodiments, and it should be noted that the following embodiments are only for explaining and illustrating the present invention and are not intended to limit the present invention. The invention is not limited to the embodiments described above, but rather, may be modified within the scope of the invention.

Example 1

A hydrogel material for treating a full-thickness burn wound surface is an ABA type triblock reticular copolymer formed by polymerizing a polyethylene glycol monomer and an N-isopropyl acrylamide monomer, the copolymer comprises a mussel bionic tissue adhesive group and a silver nanoparticle anchoring group, silver nanoparticles are loaded on the hydrogel, and cyclosporine A is loaded on the surface and inside of the hydrogel. The ABA type triblock net copolymer has the following structural formula:

the gel has temperature-sensitive characteristic (as shown in figure 1), is in a liquid state at normal temperature or below body temperature, is converted into a gel state at body temperature or when contacting body surfaces, is convenient to store and transport, and is beneficial to surgical use such as spraying or injection.

The preparation method of the hydrogel refers to ACS applied materials & interfaces, 2017; 9221-9225 ", the method specifically comprises: (1) firstly, synthesizing a copolymer from an N-isopropyl acrylamide monomer and a polyethylene glycol monomer by using a RAFT (reversible addition-fragmentation chain transfer) polymerization method;

(2) then, replacing the active ester in the copolymer obtained in the step (1) with a mussel bionic tissue adhesive group, and introducing the mussel bionic tissue adhesive group into the polymer;

(3) adding mercaptoethylamine into the product obtained in the step (2) to carry out chemical grafting reaction;

(4) and (4) loading the substance obtained in the step (3) with cyclosporine A and silver nanoparticles to obtain the hydrogel material.

Wherein the number average molecular weight of the polyethylene glycol is 8000-10000, and the mass ratio of the polyethylene glycol monomer to the N-isopropylacrylamide monomer is 1: 3-4. Adding a cross-linking agent methylene bisacrylamide, an initiator ammonium persulfate and a catalyst dithiocarbamate in the polymerization reaction process of the step (1).

Experimental example 1

A rat severe burn model is constructed, the hydrogel material obtained in example 1 (the mass ratio of the polyethylene glycol monomer to the N-isopropylacrylamide monomer is 1:3, and the number average molecular weight of the polyethylene glycol is 8000) is used for repairing after burn, the protective effect of the hydrogel material obtained in example 1 on the local tissue recovery of rats after burn and the inhibition effect of systemic inflammatory response are discussed, and the method is as follows:

40 rats were divided into 4 groups, Control group (Control), model group (Burn), positive Control group (Burn + Intrasite Gel), and experimental group (Burn + hydrogel). All rats were shaved on the back, general anesthetized with 1% sodium pentobarbital 1mL, and the area was 30% of the total surface area (TBSA-K W0.5, K-0.9, W is mouse body weight) was taken as the burn area. All rats except the control group were anesthetized and then scalded in 99 ℃ water for 15 seconds, and the control group rats were anesthetized and then incubated in 37 ℃ water for 15 seconds.

Wound surface was treated 1d after burn. In the experimental group, the wound surface is treated by the novel CsA-carrying hydrogel dressing; in the positive control group, the wound surface is treated by QINGDEJIA (Intrasite Gel, a clinical common hydrogel dressing); the model group was not dosed and the remaining treatments were consistent. After the rat is anesthetized, the back is cleaned and disinfected by chlorhexidine, the drug is administered according to grouping conditions, the administration thickness is 3-5 mm, and the drug is prevented from falling off. At 3, 7, 10 and 14d after the burn, the healing process of the wound surface is measured and recorded by adopting Image Pro Plus software, the area of the scab surface, the healing rate of the wound surface and the complete healing time are calculated, and the morphological change of the wound surface is observed.

The statistical experimental results are shown in table 1:

TABLE 1

Experimental example 2

"ACS applied materials & interfaces.2017; 9221-9225 "the hydrogel prepared in the rat model of severe burn was used as the positive control group 2, and the results are shown in table 2 by loading CsA compared with the experimental group of the present invention:

TABLE 2

Experimental example 3

Collecting blood by tail vein at 3, 7, 10 and 14d after the burn of the rat, respectively collecting 4 groups of rat blood at each time point, centrifuging to obtain serum, and detecting the IL-6 and TNF-alpha (tumor necrosis factor-alpha) levels by using a Varioskan Flash multifunctional enzyme-linked immunosorbent assay (ELISA) kit; meanwhile, wound tissues are taken 14 days after burn, and structural tissue change, collagen distribution and EFG-2 expression conditions among wound granulation tissues are respectively detected. Wherein the rats in the control group are not burned, and the rats in the control group are incubated in water at 37 ℃ for 15 seconds after anesthesia.

The results obtained are shown in tables 3 and 4:

TABLE 3

TABLE 4

The experimental results show that the novel CsA-carrying hydrogel dressing can play roles in promoting the healing of the full-thickness burn wound, improving the healing speed, reducing the release of inflammatory factors in vivo, promoting the growth of endothelial cells and the like.

Claims (8)

1. The hydrogel material for treating the full-thickness burn wound surface is characterized by being an ABA type triblock reticular copolymer formed by polymerizing a polyethylene glycol monomer and an N-isopropyl acrylamide monomer, wherein the mass ratio of the polyethylene glycol monomer to the N-isopropyl acrylamide monomer is 1: 3-4, the copolymer comprises a mussel bionic tissue adhesive group and a silver nanoparticle anchoring group, silver nanoparticles are loaded on the hydrogel, and cyclosporine A is loaded on the surface and inside of the hydrogel.

2. A hydrogel material for use in the treatment of a full-thickness burn wound according to claim 1, wherein the mussel biomimetic tissue adhesive group is a dopamine group.

3. The hydrogel material for treating a full-thickness burn wound according to claim 1, wherein the silver nanoparticle anchoring group is a thiol group.

4. The hydrogel material for treating a full-thickness burn wound according to claim 1, wherein the number average molecular weight of the polyethylene glycol is 8000-10000.

5. The hydrogel material for treating a full-thickness burn wound according to claim 1, wherein the molecular structural formula of the ABA triblock reticulated copolymer is shown as formula (I):

wherein x, y and z are integers from 1 to n.

6. A method of preparing a hydrogel material for use in the treatment of a full-thickness burn wound as claimed in any one of claims 1 to 5, comprising the steps of:

(1) firstly, synthesizing a copolymer from an N-isopropyl acrylamide monomer and a polyethylene glycol monomer by using a RAFT (reversible addition-fragmentation chain transfer) polymerization method;

(2) then, replacing the active ester group in the copolymer obtained in the step (1) with a mussel bionic tissue adhesive group, and introducing the mussel bionic tissue adhesive group into the polymer;

(3) adding mercaptoethylamine into the product obtained in the step (2) to carry out chemical grafting reaction;

(4) and (4) loading the substance obtained in the step (3) with cyclosporine A and silver nanoparticles to obtain the hydrogel material.

7. The method of claim 6, wherein the synthesizing of the copolymer in step (1) further comprises adding a crosslinking agent, an initiator, and a catalyst.

8. The method of claim 7, wherein the cross-linking agent is methylene bisacrylamide, the initiator is ammonium persulfate, and the catalyst is dithiocarbamate.

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