CN111234163B

CN111234163B - Nanogel with antibacterial repair performance and preparation method and application thereof

Info

Publication number: CN111234163B
Application number: CN202010202828.0A
Authority: CN
Inventors: 刘文帅; 王伟伟; 孔德领; 黄平升; 张闯年
Original assignee: Institute of Biomedical Engineering of CAMS and PUMC
Current assignee: Institute of Biomedical Engineering of CAMS and PUMC
Priority date: 2020-03-20
Filing date: 2020-03-20
Publication date: 2021-08-24
Anticipated expiration: 2040-03-20
Also published as: CN111234163A

Abstract

The invention discloses a nanogel with antibacterial repair performance, which comprises the following raw materials: the composition comprises PCEC, QAS and diisocyanate, wherein the molar ratio of the PCEC to the QAS to the diisocyanate is 1 (0.5-10): (1.5-11); the preparation process comprises the following steps: polymerizing, crude extracting, refining and preparing gel; PCEC and QAS are used as raw materials to prepare hydrogel, and the obtained hydrogel has good antibacterial performance on gram-positive bacteria, gram-negative bacteria, fungi and other microorganisms, and is expected to be used as a spectrum antibacterial dressing; simple preparation process, degradability, good biocompatibility and good commercial prospect.

Description

Nanogel with antibacterial repair performance and preparation method and application thereof

Technical Field

The invention relates to the technical field of research and development of new biomedical materials and related medical instruments, in particular to nanogel with antibacterial repair performance and a preparation method and application thereof.

Background

Infection is one of the most common serious complications of wounds and other open wounds, and the difficulty in healing wounds caused by bacterial infection is a significant clinical problem. Bacterial resistance to antibiotics abuse presents a great deal of difficulty in the treatment of infections. With the rapid development of materials science and engineering technology, a plurality of novel medical antibacterial dressings come into force, and biological medical materials are endowed with certain antibacterial property by physical or chemical methods, so that the propagation of bacteria is reduced, and finally, the occurrence of diseases related to bacterial infection is reduced.

The hydrogel is a novel functional polymer material with a three-dimensional network structure, and is obtained by crosslinking water-soluble or hydrophilic polymers through chemical crosslinking or physical action. Hydrogel materials have good properties and are of great interest in the biomedical field. Firstly, hydrogels have a network-like porous structure similar to the extracellular matrix, approaching living tissue than any other synthetic biomaterial; secondly, the surface of the hydrogel is not easy to adhere substances such as protein and the like, so the hydrogel has good biocompatibility when contacting blood, body fluid and human tissues. In addition, the hydrogel not only contains high moisture, but also is very soft, so that adverse reactions of surrounding tissues can be reduced; moreover, the hydrogel has excellent permeability due to the three-dimensional network structure, facilitates transportation of nutrients and metabolites, and can maintain survival and propagation of cells around the hydrogel. Therefore, the hydrogel has wide applications in various fields such as tissue repair and regeneration, drug delivery, artificial skin, biosensing, and the like.

Hydrogel with antibacterial activity is a hotspot of current wound dressing research. Commonly used antibacterial agents can be classified into inorganic antibacterial agents and organic antibacterial agents. The currently commonly used inorganic antibacterial agent is silver particles or nano silver, and the antibacterial hydrogel containing the nano silver has good antibacterial activity, but the nano silver is easily enriched in vivo and difficult to be eliminated in vitro, so that potential biological safety is generated, and the wide application of the antibacterial hydrogel is hindered. The organic antibacterial agent comprises traditional antibiotics, quaternary ammonium salt and the like, and the antibacterial hydrogel containing the antibiotics can be used for preventing infection, but the antibiotics are easy to cause the bacteria to generate drug resistance. The quaternized chitosan hydrogel is another common external antibacterial biological product, has a spectral antibacterial effect, and cannot generate drug resistance; however, the synthesis route of the quaternized chitosan is complex, high in cost and certain in cytotoxicity.

The hydrogel usually has a three-dimensional cross-linked structure and abundant moisture, and can effectively maintain the moist environment of a wound surface. In addition, hydrogels allow gas exchange and can be designed to be biodegradable, thereby avoiding additional surgical resection and secondary trauma. More importantly, antibiotics can be encapsulated in hydrogels to prevent bacterial infection, but overuse of antibiotics can lead to bacterial resistance. Another type of antimicrobial hydrogel commonly encapsulates biocides, including silver nanostructures, graphene oxide nanoflakes, metal-organic frameworks, to deliver hydrogels to build composite systems. However, these organic bactericides require external light stimulation and may cause cytotoxicity, and thus, the biocompatibility of the corresponding antibacterial hydrogel is a major problem in clinical applications.

The utilization of the inherent antibacterial cationic polymers such as Chitosan (CS), quaternary ammonium chitosan (QCS), cationic peptides, etc. may be a feasible and effective way to develop long-acting antibacterial hydrogels. However, it is noted that the antimicrobial hydrogels based on quaternary ammonium CS polymers generally have poor in vivo antimicrobial activity and require repeated treatments or use in combination with an excess of active ingredients (e.g., antibiotics) to improve antimicrobial efficacy. The cationic peptide hydrogel has the characteristics of easy degradation, unstable salt, high hemolysis rate, high toxicity and the like. Therefore, under the condition that toxic drugs or antibiotics are not used to accelerate wound healing, the development of hydrogel with high inherent antibacterial ability and long-acting effect is urgently needed.

Therefore, how to provide a nanogel with high safety and antibacterial repair performance is a problem that needs to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the invention provides a degradable self-assembled nano antibacterial hydrogel and a preparation method thereof, wherein PCEC and QAS are used as raw materials to prepare the hydrogel, and the obtained hydrogel has good antibacterial performance on gram-positive bacteria, gram-negative bacteria, fungi and other microorganisms and is expected to be used as an antibacterial dressing; the hydrogel prepared by the invention has simple preparation process, good degradability and biocompatibility and good commercial prospect.

In order to achieve the purpose, the invention adopts the following technical scheme:

a nanogel with antibacterial repair performance comprises the following raw materials: the composition comprises PCEC, QAS and diisocyanate, wherein the molar ratio of the PCEC to the QAS to the diisocyanate is 1 (0.5-10): (1.5 to 11).

The technical effect achieved by the technical scheme is as follows: the invention adopts cation quaternary ammonium salt QAS with high antibacterial activity and no cytotoxicity and biodegradable polyester polymer PCEC to prepare the antibacterial material, and the antibacterial polymer material is synthesized by a one-step method in the presence of the cross-linking agent diisocyanate, and the preparation process is simple; the content of the antibacterial agent is flexibly regulated and controlled by adjusting the molar ratio of the quaternary ammonium salt micromolecules to the polyester macromolecules; the hydrogel binds to lipids or proteins on the bacterial cell membrane, denaturing the proteins, altering the permeability of the cell membrane, and simultaneously damaging the integrity of the cell wall, causing the cell wall to tend to lyse until death. On the other hand, the antibacterial gel can enter bacteria by endocytosis, adsorb anionic active substances in cells, such as enzyme, protein, nucleic acid molecules and the like, disturb normal anabolic pathways of the cells and kill the bacteria. Therefore, the nanogel has low toxicity to cells, can be degraded into small molecules and is finally discharged out of the body; moreover, the hydrogel prepared by the method has a microporous structure, so that the proliferation of cells can be promoted, and the healing of wounds can be promoted.

The dihydroxy and oxadiazole group-purified Quaternary Ammonium Salts (QAS) enhance cell membrane binding by chemically conjugated poly (. epsilon. -caprolactone) poly (ethylene glycol) poly (. epsilon. -caprolactone) copolymers using a one-step polycondensation Process (PCEC). The amphiphilic PCEC-QAS nano particles are subjected to spontaneous self-assembly and non-covalent accumulation under the high-temperature heating-cooling cyclic treatment, so that the physical crosslinking hydrogel with gel-sol irreversibility and a porous structure is formed. The PCEC-QAS nano-particles enable the hydrogel to have good broad-spectrum antibacterial action on gram-positive bacteria and gram-negative bacteria. The highly porous network within the hydrogel allows for cell proliferation and migration, and thus, the hydrogel can be used as a tissue regeneration scaffold for wound healing. The PCEC-QAS hydrogel can be completely degraded in vivo, and has good biodegradability, skin compatibility and system biosafety in mice. In vitro and in vivo experiments show that the hydrogel has good internal anti-inflammatory effect, and can accelerate the regeneration of wound skin under the condition of not using antibiotics, cytokines or treatment cells. Therefore, the PCEC-QAS hydrogel can be expected to be used as a promising wound dressing, can kill microorganisms, and has great application potential on wound surfaces which are difficult to heal.

As a preferable technical scheme of the invention, the molecular weight of the PCEC is 3000-10000 Da.

As a preferred embodiment of the present invention, the diisocyanate includes any one of aliphatic, alicyclic or alkanyl diisocyanates.

A preparation method of nanogel with antibacterial repair performance comprises the following steps:

1) fully dissolving PCEC, QAS and diisocyanate in a polar organic solvent according to a molar ratio, adding a catalyst dibutyltin dilaurate, and reacting at 40-70 ℃ for 24-48 hours to obtain a PCEC-QAS copolymer;

2) adding a nonpolar solvent into the PCEC-QAS copolymer for crude extraction, and collecting precipitates to obtain a PCEC-QAS crude product;

3) dissolving the PCEC-QAS crude product in an N, N-dimethylformamide solvent, dropwise adding the solution into ultrapure water, dialyzing for 12-72 hours, and freeze-drying the dialyzed product to obtain PCEC-QAS nano freeze-dried powder; the ultrapure water dialysis can remove impurities such as small molecular compounds, and the nanoparticles can be formed by self-assembly.

4) And dissolving the PCEC-QAS nano freeze-dried powder in water, heating to 60 ℃, and cooling to room temperature to obtain the nano gel.

The technical effect achieved by the technical scheme is as follows: when the nanogel is prepared, three raw materials can be polymerized together by one-step catalytic reaction, the reaction condition is moderate, the time is short, and the efficiency is high; the PCEC-QAS copolymer is put into a nonpolar solvent to be coarsely extracted, so that raw materials (HDMI and QAS) which do not participate in the reaction can be removed; the PCEC-QAS nano antibacterial agent after freeze-drying is dissolved in water and then is heated and cooled, so that hydrogel with excellent performance can be prepared without an additional conveying system and an organic cross-linking agent. The PCEC-QAS antimicrobial agent is low in cost, non-toxic, and does not require triggering of antimicrobial activity upon light irradiation. All these advantages will facilitate its clinical application. At this temperature, the aggregation between the nanoparticles is enhanced.

As a preferred embodiment of the present invention, the polar organic solvent includes: any one of N, N-dimethylformamide, dimethyl sulfoxide, propylene glycol, glycerol, isopropanol or ethanol.

As a preferable technical scheme of the invention, in the step 1), the mass ratio of the total mass of the raw materials to the polar solvent is 1 (1-2).

As a preferable technical scheme of the invention, in the step 1), the mass ratio of the total mass of the raw materials to the dibutyltin dilaurate is 1: (10-100).

As a preferred embodiment of the present invention, the nonpolar solvent includes: petroleum ether, benzene or diethyl ether.

As a preferable technical scheme of the invention, the volume ratio of the PCEC-QAS copolymer solution to the nonpolar solvent is 1 (5-20).

As a preferable technical scheme of the invention, the crude extraction condition is that the crude extraction is kept still for 6-24 hours at the temperature of 2-8 ℃.

As a preferred technical scheme of the invention, the volume ratio of the PCEC-QAS crude product to the N, N-dimethylformamide is (1-2): 1.

as a preferable technical scheme of the invention, in the step 3), the dropping speed is 30-100 drops/min.

As the preferable technical scheme of the invention, the freeze drying condition is drying for 24-48 h at-30-60 ℃.

As a preferable technical scheme of the invention, the final concentration of the PCEC-QAS nano freeze-dried powder in water is 0.1-0.4g/ml, and the heating time is 5-30 min.

The application of the nanogel prepared by the preparation method of the nanogel with antibacterial repair performance in preparing a medicament for preventing wound infection and promoting tissue repair is disclosed.

According to the technical scheme, compared with the prior art, the invention has the following technical effects:

1) the antibacterial hydrogel prepared by the method adopts PCEC modified by novel alkylated micromolecular quaternary ammonium salt as a raw material, has good antibacterial activity and broad-spectrum antibacterial effect, and also has good antibacterial effect on drug-resistant bacteria.

2) The gel prepared by the invention is formed by self-aggregation of PCEC-QAS nano particles, and no additional gel or other carriers are needed to be used as auxiliary materials of the antibacterial agent.

3) The PCEC-QAS nano antibacterial agent can enhance the interaction with bacteria, adhere to the surface of the bacteria and even enter the interior of the bacteria, and enhance the antibacterial activity.

4) The antibacterial hydrogel prepared by the method can be retained at an infected part for a long time without multiple times of administration, and has a long-term antibacterial effect.

5) The antibacterial hydrogel prepared by the method is degradable, and the residence time at the infected part is controllable. Antibacterial hydrogel with different molecular weights and different degradation speeds can be adopted according to the requirements of wounds, and the antibacterial hydrogel is matched with the wound repair time, so that the healing of the wounds can be better promoted; when the molecular weight reaches 10000Da, the degradation speed is about 2-3 months, and when the molecular weight is 3000Da, the degradation speed is about 2 weeks.

In conclusion, the nano hydrogel prepared by the invention has a porous structure, and compared with the prior art,

1) no extra hydrogel loaded antibacterial agent is needed, which is an advantage in preparation technology;

2) only contains one component of the nano antibacterial agent, and compared with the antibacterial gel loaded with inorganic metal particles, the antibacterial gel can generate the sterilization effect without external illumination;

3) can be absorbed, is non-toxic and does not contain metal ions or metal nanoparticles;

4) is beneficial to the growth of tissue cells to the interior of the gel and promotes the healing of wounds. The nanogel can be completely degraded into small molecular compounds PEG, CL and QAS, and has no potential safety problem.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a scheme showing the synthesis of the PCEC-QAS gel in example 1;

FIG. 2 is a nuclear magnetic spectrum of the PCEC-QAS nano lyophilized powder of example 1;

FIG. 3 is an infrared spectrum of the PCEC-QAS nano lyophilized powder of example 1;

FIG. 4 is a graph representing the particle size and potential of the PCEC-QAS nano-solution in example 1;

FIG. 5 is an SEM photograph of a gel of example 1;

FIG. 6 is a pictorial view showing the appearance of the gel of example 1 before and after it is formed (A: PCEC-QAS aqueous solution; B: PCEC-QAS gel);

FIG. 7 is a graph showing a statistic of cytotoxicity of PCEC-QAS gel prepared in example 1 on HUVEC cells;

FIG. 8 is an optical image of a skin infected wound before and after repair;

FIG. 9 is a graph showing the effect of the gel on the inhibition of bacteria in example 1;

FIG. 10 the accompanying drawing is a pathology examination of skin infected wounds before and after repair.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

1) polymerization: fully dissolving PCEC, QAS and 1, 6-hexamethylene diisocyanate in N, N-dimethylformamide according to the molar ratio of 1:1:2, adding a catalyst dibutyltin dilaurate, heating to 50 ℃, and reacting for 24 hours at the temperature to obtain a PCEC-QAS copolymer; the reaction process is shown in figure 1;

2) crude extraction: adding the PCEC-QAS copolymer into petroleum ether for crude extraction, collecting precipitates, carrying out suction filtration, washing for 3 times, and carrying out vacuum drying to obtain a white solid PCEC-QAS crude product;

3) refining: dissolving the PCEC-QAS crude product in N, N-dimethylformamide solvent, dripping into ultrapure water for dialysis for 24 hours, freeze-drying the dialysis product to obtain PCEC-QAS nano freeze-dried powder, and performing nuclear magnetic resonance¹H NMP, infrared spectroscopy and other methods are used for detecting the chemical structure;

¹h NMR analysis

Testing by using deuterated dimethyl sulfoxide as a solvent in a nuclear magnetic resonance instrument Bruker 400; the result is shown in FIG. 2, and the chemical shift is 3.51ppm, which is the characteristic proton peak of the PEG segment in the PCEC; chemical shifts 3.98, 2.27, 1.53, 1.29ppm are characteristic proton peaks of PCL segment in PCEC; the characteristic peaks at 8.01 and 7.63ppm are attributed to the proton peaks of the phenyl on the small molecular quaternary ammonium salt QAS. The above analysis demonstrates the correctness of the chemical structure of the PCEC-QAS of the example;

infrared spectroscopic analysis

Measured on a Nicolet MAGNA-IR 550 type infrared spectrometer by using KBr pellets, as shown in FIG. 3, 3500-3300cm^-1The broad peak therebetween is a stretching vibration absorption peak of the terminal hydroxyl group of the PCEC. 3000-2800cm^-1Corresponding to the stretching vibration peak of methylene in the PCEC; 1724cm^-1Characteristic absorption peaks of the carbonyl group in the ester bond of PCEC, 1194 and 1247cm^-1Is the stretching vibration peak of the PCEC ether bond;

4) preparation of PCEC-QAS nano-particle

Weighing a proper amount of PCEC-QAS freeze-dried powder, dissolving the PCEC-QAS freeze-dried powder in distilled water, fully stirring the solution to completely dissolve the powder to obtain a nanoparticle solution, and testing the particle size and the potential of the nanoparticle solution, wherein the particle sizes of nanoparticles with different concentrations are 100-150 nm, and the surface potential is positive charge as shown in figure 4;

5) preparation of hydrogels

Heating the nanoparticle aqueous solution to 60 deg.C, and cooling to room temperature to obtain hydrogel (see FIG. 5). The hydrogel was freeze-dried to obtain a freeze-dried sample, and the microstructure thereof was observed by SEM. As shown in fig. 6, the nanogel has a highly cross-linked three-dimensional network structure inside, and the pore size is in the micrometer scale.

Test for biocompatibility and antibacterial Activity of the Nanogel prepared in this example

In vitro cytotoxicity evaluation of Nanogels

The invention adopts a CCK-8 method to detect the killing effect of PCEC-QAS on umbilical vein endothelial cells (HUVEC). The PCEC-QAS gel is dissolved in PBS to prepare different concentrations (1-10 mg/mL). mu.L of PCEC-QAS solution was added to wells of HUVEC cell culture plates (5 duplicate wells per group), incubated for 24 hours, and then acted on with CCK-8 solution (20. mu.L, 5mg/mL) for 4 hours. The absorbance at 450nm was measured and the magnitude of cytotoxicity of the material was calculated in comparison with untreated cells. As shown in FIG. 7, the cell survival rate was about 100% with the increase of the concentration of PCEC-QAS, demonstrating that PCEC-QAS does not produce cytotoxicity.

Reference GB/T16886.5-2003, section 5 of medical device biology evaluation: in vitro cytotoxicity test, as can be seen from the experimental results, the survival rate of the cells is more than 75%, and the cytotoxicity is graded as grade I, so that the PCEC-QAS has no cytotoxicity.

Evaluation of gel hemolytic Properties

According to GB/T16886.4-2003/ISO 10993-4:2002, section 4 of the biological evaluation of medical devices: the hemolysis of PCEC-QAS was calculated according to the hemolysis ratio (test group OD-negative group OD)/(positive group OD-negative group OD) × 100%, as required in the blood interaction test selection. The experimental results (table 1) show that the hemolysis rate of PCEC-QAS is less than 5%, and the medical appliance use requirements are met.

TABLE 1 hemolysis rate of PCEC-QAS nanohydrogel

Antimicrobial Property test of hydrogel

Qualitative test method

Test groups: sterilizing the PCEC-QAS gel, placing 0.1mL of bacterial liquid (MRSA bacteria) on the hydrogel, and culturing for 12 hours;

distilled water group: sterilizing the PCEC-QAS gel, putting 0.1mL of bacterial liquid into distilled water, and culturing for 12 hours;

chitosan group: sterilizing the PCEC-QAS gel, putting 0.1mL of bacterial liquid into a chitosan solution, and culturing for 12 hours;

respectively placing the three groups of cultured bacterial liquids on a solid culture medium, and uniformly coating the three groups of cultured bacterial liquids by using a coater; the culture was carried out for 0.5 hour, then turned over, and the culture was continued in a constant temperature incubator at 37 ℃ for 24 hours. As shown in fig. 8, the distilled water group and the chitosan group had a large number of colonies, while the experimental group had no colonies, indicating that the hydrogel had excellent antibacterial activity.

Quantitative test method

And (3) quantitatively testing the antibacterial performance of the hydrogel by adopting a shaking culture method. 40 tubes were divided into 4 groups of 10 tubes each. Sucking 2mL of nutrient broth into each test tube by using a pipette, adding 2mL of PCEC-QAS solution into the 1 st test tube of each group, uniformly mixing, sucking 2mL of uniform mixing solution from the 1 st tube of each group, adding into the 2 nd tube of each group, repeating the steps until reaching the 9 th tube, sucking 2mL of uniform mixing solution from the 9 th tube, removing, and taking the 10 th test tube as a bacteria control group without adding liquid medicine. 0.1mL of bacterial liquid is added into each of 3 groups of test tubes, 9 test tubes are taken, and the dilution step is carried out according to the above steps, and the test tubes are not added with bacterial liquid and are used as a liquid medicine control group. The tube was placed in an incubator at 37 ℃ and cultured with shaking for 24 hours.

As can be seen from Table 2, the hydrogel bacteria have better antibacterial activity, the Minimum Inhibitory Concentrations (MIC) of the hydrogel bacteria to staphylococcus aureus (MRSA) and escherichia coli (E.coli) are respectively 0.1mg/mL and 0.05mg/mL, and the hydrogel bacteria are better than small molecular quaternary ammonium salt and quaternized chitosan.

TABLE 2 minimal inhibitory concentrations (mg/mL) of the compounds against E.coli and S.aureus

In vivo bacterial infection skin wound repair test

The SD rat is subjected to general anesthesia, the SD rat is fixed on an operating table after skin preparation is carried out on the back operation area, a 0.8cm circular wound surface with open full-layer skin defect is manufactured on the back by scissors till the deep layer of the muscle fascia, and a full-layer skin wound model is created. Then infected with MRSA and the assay was divided into three groups: untreated group, chitosan hydrogel (Baiyunshan) control group, nanogel experimental group; wound healing was observed at different time points. As shown in Table 3, the wound area of each group was significantly reduced in 4, 8 and 12 days, and the healing rate was gradually increased. The healing rate of the wound surface of the experimental group at the same time point is superior to that of the control group, and the healing rate of the PCEC-QAS wound surface reaches 98.1 +/-4.2 percent and is obviously higher than that of a blank control group (48.4 +/-4.6 percent) and a chitosan hydrogel control group (60.7 +/-3.8 percent) in 12 days. This result demonstrates that PCEC-QAS has a better antimicrobial activity against MRSA, and that hydrogels can further promote wound healing.

Table 3 wound healing rate at different time points (n ═ 5, x ± s,%)

P <0.01 compared to placebo; p <0.01 compared to the chitosan hydrogel control group.

As shown in fig. 9, after 12 days, the experimental group had substantially healed, the wound surface was epithelialized, the crust skin was exfoliated, the wound surface was substantially healed, scar tissue was formed, the wound surface was substantially covered with hair, and it was confirmed that the dermis layer had substantially recovered its function.

The skin repair, H & E staining and Masson staining were studied by drawing material. The results show (fig. 10), day 4, the experimental group had abundant basic structure of wound surface epithelial cells and collagen fibers, and fewer inflammatory cells. On day 8, the epithelium and connective tissue in the experimental group were highly uniform, forming more fibroblasts and epithelial cells. On day 12, the wound surface of the experimental group had intact epidermis and intact collagen fiber structure, which was substantially identical to normal skin tissue. The PCECQAS nano hydrogel has better antibacterial effect and strong killing effect on MRSA, thereby accelerating the repair of skin tissues.

In conclusion, the prepared nano hydrogel has obvious curative effects of resisting bacteria and inflammation and promoting wound repair. Compared with chitosan hydrogel, the chitosan hydrogel has more effective antibacterial activity; meanwhile, the hydrogel has better biocompatibility and is very suitable for treating infected wounds.

Example 2

1) polymerization: fully dissolving PCEC, QAS and 1, 6-hexamethylene diisocyanate in dimethyl sulfoxide according to the molar ratio of 1:0.5:1.5, adding a catalyst dibutyltin dilaurate, heating to 40 ℃, and reacting at the temperature for 30 hours to obtain a PCEC-QAS copolymer;

2) crude extraction: adding the PCEC-QAS copolymer into benzene for crude extraction, collecting precipitates, carrying out suction filtration, washing for 3 times, and carrying out vacuum drying to obtain a white solid PCEC-QAS crude product;

3) refining: dissolving the PCEC-QAS crude product in an N, N-dimethylformamide solvent, dropwise adding the solution into ultrapure water, dialyzing for 12 hours, and freeze-drying the dialyzed product to obtain PCEC-QAS nano freeze-dried powder;

4) preparation of hydrogels

Weighing a proper amount of PCEC-QAS freeze-dried powder, dissolving the powder in distilled water, fully stirring the solution to completely dissolve the powder to obtain a nanoparticle solution, heating the nanoparticle solution to 60 ℃, and then cooling the nanoparticle solution to room temperature to obtain hydrogel.

Example 3

1) polymerization: mixing the PCEC, QAS and 1, 6-hexamethylene diisocyanate according to the proportion of 1: fully dissolving the mixture in propylene glycol according to the molar ratio of 10:11, adding a catalyst dibutyltin dilaurate into the mixture, heating the mixture to 70 ℃, and reacting the mixture for 48 hours at the temperature to obtain a PCEC-QAS copolymer;

2) crude extraction: adding the PCEC-QAS copolymer into ether for crude extraction, collecting the precipitate, carrying out suction filtration, washing for 3 times, and carrying out vacuum drying to obtain a white solid PCEC-QAS crude product;

3) refining: dissolving the PCEC-QAS crude product in an N, N-dimethylformamide solvent, dropwise adding the solution into ultrapure water, dialyzing for 72 hours, and freeze-drying the dialyzed product to obtain PCEC-QAS nano freeze-dried powder;

4) preparation of hydrogels

Example 4

1) polymerization: fully dissolving PCEC, QAS and 1, 6-hexamethylene diisocyanate in glycerol according to the molar ratio of 1:5:5, adding a catalyst dibutyltin dilaurate into the mixture, heating the mixture to 60 ℃, and reacting the mixture for 40 hours at the temperature to obtain a PCEC-QAS copolymer;

3) refining: dissolving the PCEC-QAS crude product in an N, N-dimethylformamide solvent, dropwise adding the solution into ultrapure water, dialyzing for 48 hours, and freeze-drying the dialyzed product to obtain PCEC-QAS nano freeze-dried powder;

4) preparation of hydrogels

Example 5

1) polymerization: fully dissolving PCEC, QAS and 1, 6-hexamethylene diisocyanate in isopropanol according to the molar ratio of 1:8:6, adding a catalyst dibutyltin dilaurate into the isopropanol, heating to 45 ℃, and reacting for 35 hours at the temperature to obtain a PCEC-QAS copolymer;

3) refining: dissolving the PCEC-QAS crude product in an N, N-dimethylformamide solvent, dropwise adding the solution into ultrapure water, dialyzing for 50 hours, and freeze-drying the dialyzed product to obtain PCEC-QAS nano freeze-dried powder;

4) preparation of hydrogels

Example 6

1) polymerization: mixing the PCEC, QAS and 1, 6-hexamethylene diisocyanate according to the proportion of 1: fully dissolving the mixture in ethanol according to the molar ratio of 4:7, adding a catalyst dibutyltin dilaurate into the mixture, heating the mixture to 55 ℃, and reacting the mixture for 45 hours at the temperature to obtain a PCEC-QAS copolymer;

3) refining: dissolving the PCEC-QAS crude product in an N, N-dimethylformamide solvent, dropwise adding the solution into ultrapure water, dialyzing for 65 hours, and freeze-drying the dialyzed product to obtain PCEC-QAS nano freeze-dried powder;

4) preparation of hydrogels

Example 7 verification of the Effect of molar ratio of PCEC and QAS on hydrogel antimicrobial results

A hydrogel was prepared in the same manner as in example 1 to obtain control 1;

the molar ratio of PCEC to QAS in example 1 was changed to 1:0.5, marking as test group 1 when other operations are unchanged;

the molar ratio of PCEC to QAS in example 1 was changed to 1: 4, marking as a test group 2 when other operations are unchanged;

the molar ratio of PCEC to QAS in example 1 was changed to 1:5, marking as a test group 3 when other operations are unchanged;

the molar ratio of PCEC to QAS in example 1 was changed to 1:8, marking as a test group 4 when other operations are unchanged;

the molar ratio of PCEC to QAS in example 1 was changed to 1: 10, marking as test group 5 if other operations are unchanged;

the hydrogels prepared in control 1 and test groups 1-5 were tested according to the method for testing antibacterial performance of hydrogel in example 1, and the results are shown in table 4;

TABLE 4 MIC values (mg/mL) of different materials for MRSA and E.coli bacteria

As can be seen from table 4, with PCEC: the increase of QAS proportion, the quaternization substitution degree can increase, can reach the maximum value, just there is not obvious improvement at last, but the quantity of quaternary ammonium salt does not need higher content just can reach antibiotic effect, and when QAS content increased, antibiotic effect did not very obvious promotion, consequently, synthesize antibiotic effect and manufacturing cost and consider, finally with PCEC: QAS is controlled at 1: 1.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The nanogel with antibacterial repair performance is characterized by comprising the following raw materials: the composition comprises PCEC, QAS and diisocyanate, wherein the molar ratio of the PCEC to the QAS to the diisocyanate is 1 (0.5-10): (1.5-11);

wherein, the PCEC is shown as formula I; QAS is shown as formula II, and n is 2-12;

2. the nanogel with antibacterial repairing performance according to claim 1, wherein the molecular weight of the PCEC is 3000-10000 Da.

3. The nanogel with antibacterial repair properties according to claim 1, wherein the diisocyanate comprises any one of alicyclic diisocyanate or alkanyl diisocyanate.

4. A preparation method of nanogel with antibacterial repair performance is characterized by comprising the following steps:

1) polymerization: weighing each raw material of the nanogel as defined in claim 1, fully dissolving the PCEC, the QAS and the diisocyanate in a polar organic solvent according to a molar ratio, adding dibutyltin dilaurate, and reacting for 24-48 h at 40-70 ℃ to obtain a PCEC-QAS copolymer;

2) crude extraction: adding a non-polar solvent into the obtained PCEC-QAS copolymer for crude extraction, and collecting precipitates to obtain a PCEC-QAS crude product;

3) refining: dissolving the PCEC-QAS crude product in an N, N-dimethylformamide solvent, dropwise adding the solution into ultrapure water for dialysis for 12-72h, and freeze-drying the dialysis product to obtain PCEC-QAS nano freeze-dried powder;

4) preparing a gel: and dissolving the PCEC-QAS nano freeze-dried powder in water, heating to 60-70 ℃, and cooling to room temperature to obtain the nano gel.

5. The method for preparing nanogel with antibacterial repair performance according to claim 4, wherein the polar organic solvent comprises: any one of N, N-dimethylformamide, dimethyl sulfoxide, propylene glycol, glycerol, isopropanol and ethanol.

6. The preparation method of the nanogel with the antibacterial repairing performance according to claim 4 is characterized in that in the step 1), the mass ratio of the total mass of the raw materials to the polar solvent is 1 (1-2).

7. The method for preparing nanogel with antibacterial repair performance according to claim 4, wherein the nonpolar solvent comprises: any one of petroleum ether, benzene and diethyl ether.

8. The preparation method of the nanogel with the antibacterial repair performance as claimed in claim 4, wherein the volume ratio of the PCEC-QAS copolymer solution to the nonpolar solvent is 1 (5-20).

9. Use of the nanogel prepared by the preparation method according to any one of claims 4 to 8 in preparation of drugs for preventing wound infection and promoting tissue repair.