CN112375250A

CN112375250A - Nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge and preparation method thereof

Info

Publication number: CN112375250A
Application number: CN202011119051.8A
Authority: CN
Inventors: 叶志义; 王贵学; 陈雪
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2020-10-19
Filing date: 2020-10-19
Publication date: 2021-02-19

Abstract

The invention relates to the field of materials, and particularly discloses a nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge and a preparation method thereof. The invention combines the broad-spectrum antibacterial property of nano-silver, loads nano-particles with good antibacterial effect on chitosan and polyvinyl alcohol carriers, prepares an antibacterial sponge by the biocompatibility of the chitosan and the mechanical property of the polyvinyl alcohol, is applied to the field of biomedicine, and provides an optimal environment for wound healing. The invention solves the problem that the infection risk of patients is reduced only by taking antibiotics to generate drug resistance, and the minimum inhibitory concentration of the nano-silver in the antibacterial sponge is 5-10 times lower than that of the nano-silver researched by the existing literature, thereby reducing the material cost of similar materials and playing a positive role in the popularization and application of the nano-silver antibacterial material.

Description

Nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge and preparation method thereof

Technical Field

The invention relates to the field of materials, in particular to a nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge and a preparation method thereof.

Background

Chitosan is obtained by deacetylation of chitin (chitin) which is widely existed in nature, mainly exists in shrimp, crab, insect, fungus, plant body, etc., and is the only basic polysaccharide existing in nature. The chitosan is from organism sources, so that the chitosan has good biocompatibility, biodegradability, reproducibility, no toxicity, no irritation and a series of biological activities such as antibiosis, anticancer, anticoagulation and the like. In addition, the chitosan has good film forming property, high moisture absorption and retention property and good permeability, so that the chitosan can be widely applied to the fields of biological medicines and the like.

The nano silver has large specific surface area, high surface activity and strong adsorption capacity, and has broad-spectrum antibacterial activity. The bactericidal effect of the silver-containing antibacterial agent is hundreds of times of that of common silver, and the silver-containing antibacterial agent has extremely strong bactericidal activity and permeability; in addition, the nano silver particles can be combined with active groups in protein molecules of thalli to destroy the protein structure of the thalli, so that the propagation of pathogenic bacteria is inhibited. The nano silver is used as a broad-spectrum antibacterial agent and has no drug resistance, which is incomparable with the traditional antibacterial agent. With the increase of drug resistance of pathogenic bacteria to antibacterial agents, the research and application of nano silver in the antibacterial field are receiving wide attention.

Polyvinyl alcohol is a water-soluble polyhydroxyl polymer. The molecular chain of the polyvinyl alcohol has a large amount of hydroxyl groups, and the polyvinyl alcohol has excellent water solubility and film forming property, and good mechanical property and biocompatibility. Can be naturally decomposed in a short time in nature, has no pollution, and is a good green and environment-friendly product. Patent 201010248219.5 discloses a chitosan/polyvinyl alcohol sponge dressing containing nano silver, which is prepared by reacting chitosan and polyvinyl alcohol with formaldehyde, sodium dodecyl sulfate, sodium bicarbonate, etc. to form flocculent precipitate, then solidifying at 50-60 deg.C, washing, drying, wherein polyethylene glycol is used as reducing agent to reduce silver nitrate, polyethylene glycol is a polymer, which is non-toxic at low concentration, but can produce certain uncomfortable reactions at higher concentration, such as hemolysis, etc., in addition, more chemical reagents are added in the preparation method, which has certain harm to cells and human body.

Therefore, a novel material combining the broad-spectrum antibacterial property of nano-silver, the biocompatibility of chitosan and the mechanical property of polyvinyl alcohol is urgently needed, and the novel material is used for preparing a medical material with stronger antibacterial activity and provides a good healing environment for wounds such as antibiotic drug-resistant bacterial infection and the like. Meanwhile, the porosity of the sponge is improved, the sponge can absorb more exudates, an optimal environment can be provided for wound healing, the harmful effects of chemical reagents on cells and bodies are reduced, and the biocompatibility is improved.

Disclosure of Invention

In order to solve the problems, the invention provides the nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge and the preparation method thereof, the addition of the polyvinyl alcohol can improve the mechanical property, reduce the viscosity and prevent adhesion, and the addition of the nano-silver improves the porosity of the chitosan-polyvinyl alcohol antibacterial composite sponge, so that the chitosan-polyvinyl alcohol antibacterial composite sponge can absorb more exudates, can provide an optimal environment for wound healing, reduces the addition of chemical substances and improves the biocompatibility.

One of the purposes of the invention is to provide an antibacterial composition, and the specific technical scheme is as follows:

an antibacterial composition, which consists of chitosan, polyvinyl alcohol, silver nitrate, glutaraldehyde, glycerol, tannic acid, curcumin, ferric chloride, dimethyl sulfoxide and bovine serum albumin, wherein the mass part ratio of the chitosan to the polyvinyl alcohol to the silver nitrate is 2: 5: .

Further, the mass part ratio of the chitosan, the polyvinyl alcohol and the silver nitrate is as follows.

The invention also aims to provide application of the antibacterial composition in the scheme in preparation of an antibacterial composite sponge.

The invention also aims to provide application of the antibacterial composition in the scheme in improving the porosity of the antibacterial composite sponge.

The fourth purpose of the invention is to provide a preparation method of nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge, which comprises the following specific technical scheme:

a preparation method of nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge comprises the following steps,

(1) mixing and stirring a chitosan acetic acid solution and a polyvinyl alcohol solution, adding glutaraldehyde, glycerol and sodium hydroxide to adjust the pH value to be neutral, and obtaining a chitosan polyvinyl alcohol solution;

(2) dissolving curcumin in dimethyl sulfoxide to obtain curcumin dimethyl sulfoxide solution, mixing tannic acid and curcumin dimethyl sulfoxide solution, adding into mixed solution of ferric chloride, bovine serum albumin and silver nitrate, and stirring to obtain antibacterial solution;

(3) and stirring the chitosan polyvinyl alcohol solution and the antibacterial solution, standing for defoaming, freeze-drying and sterilizing to obtain the nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge.

Further, the concentration of the chitosan acetic acid solution is 0.02g/ml, and the concentration of the polyvinyl alcohol solution is 0.05 g/ml.

Further, the mixing volume ratio of the chitosan acetic acid solution to the polyvinyl alcohol solution is 1: 1.

further, the mass ratio of the curcumin to the tannic acid to the ferric chloride to the bovine serum albumin is 1: 10: 2: 20.

further, the volume ratio of the chitosan polyvinyl alcohol solution to the antibacterial liquid is 10: 1.

Further, the temperature for standing and defoaming is 4 ℃, and the time is 8 hours; the freeze-drying time was 48 h.

The tannic acid is a plant processed product of tannic acid, and is prepared from Galla chinensis by leaching with soft water, evaporating, drying, and reducing silver nitrate to obtain nanometer silver. Bovine serum albumin, a globulin in bovine serum, is a simple protein in bovine serum and is the main component of blood. Both substances have good biocompatibility due to their extracts from plants and animals.

The invention has the advantages that:

(1) the preparation method disclosed by the invention has the advantages that less chemical reagents are used in the preparation process, the animal and plant extracts such as tannic acid and bovine serum albumin have better biocompatibility, and the addition of harmful substances to cells and organisms is reduced.

(2) The sponge dressing is prepared by a freeze drying technology, the method is simple and convenient, the diameter of the prepared sponge nano particles is 50-80nm, the aperture of the sponge containing nano silver is 100-250 mu m, the porosity can reach about 80 percent, and the sponge dressing has good swelling and water retention properties, larger pores, fluffy structure and good moisture retention property.

(3) The minimum bacteriostatic concentration of the sponge dressing nano-silver prepared by the invention is 5-10 times lower than that of the sponge dressing nano-silver researched by the existing literature, the bacteriostatic effect is obviously improved, the low-concentration nano-silver particles have no obvious cytotoxicity, and the production cost is greatly reduced.

Drawings

Fig. 1 is a transmission electron microscope image of the antibacterial composite sponge with nano silver concentration of 0.0005%.

Fig. 2 is a porosity chart of the experimental group and the control group of the nano-silver antibacterial composite sponge of the present invention.

Fig. 3 is a water vapor transmission rate diagram of the nano-silver antibacterial composite sponge experimental group and the control group.

Fig. 4 is a swelling performance curve diagram of the experimental group and the control group of the nano-silver antibacterial composite sponge of the present invention.

Fig. 5 is a water retention rate chart of the nano-silver antibacterial composite sponge experimental group and the control group.

Fig. 6 is a graph showing the change of the in vitro degradation mass loss rate of the experimental group and the control group of the nano-silver antibacterial composite sponge of the present invention.

Fig. 7 is a drug release graph of the antibacterial composite sponge with nano-silver concentrations of 0.0005%, 0.001% and 0.003%.

Fig. 8 is a bacteriostatic circle diagram of the nano-silver antibacterial composite sponge experimental group and the control group.

Fig. 9 shows the cell viability of the nano-silver antibacterial composite sponge of the present invention and the control group.

Detailed Description

The present invention will be described in further detail with reference to the following examples and drawings, it being understood that the present invention is not limited to the particular examples described herein, but is capable of modification in various forms and details, and can be modified within the spirit and scope of the invention.

Example 1 preparation method of nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge

Preparing chitosan polyvinyl alcohol solution. Firstly, 2g of chitosan is weighed and dissolved in 1 percent acetic acid solution at room temperature to obtain 2 percent (w/v) chitosan solution. Then 5g of polyvinyl alcohol was dissolved in 100ml of deionized water, and heated and stirred at 90 ℃ for 5 hours to obtain a polyvinyl alcohol solution with a concentration of 5% (w/v). And finally, mixing and stirring the chitosan and the polyvinyl alcohol solution according to the ratio of 1:1 for 1h, adding 1% of glutaraldehyde and 5% of glycerol for crosslinking for 1h, and finally adding a sodium hydroxide solution for regulating the pH value to be neutral.

And (5) preparing an antibacterial liquid. Firstly, curcumin is dissolved in dimethyl sulfoxide, tannic acid, ferric chloride and bovine serum albumin, and the curcumin is respectively dissolved in pure water to prepare solutions with the concentrations of 5mg/ml, 50mg/ml, 0.5mg/ml and 0.5 mg/ml. Then 2ml of ferric chloride solution is added into bovine serum albumin solution and stirred, 0.5ml of silver nitrate solution, 1ml of silver nitrate solution and 3ml of silver nitrate solution are respectively added to prepare different concentrations, and the volume is fixed to 20ml by the bovine serum albumin solution and stirred for 1 hour. And finally, uniformly mixing the tannic acid and the curcumin solution with the same volume, adding 0.2ml of mixed solution into the mixed solution of ferric chloride and silver nitrate, and stirring for 1h to obtain the antibacterial solution. Wherein, the tannic acid is an oxidant and can reduce silver nitrate into silver, the bovine serum albumin is used as a stabilizer, TA is combined with Fe, and the silver is attached to the surface of TA-Fe to form stable nano particles.

Mixing and stirring the prepared chitosan/polyvinyl alcohol solution and the antibacterial solution according to the volume ratio of 10:1, standing and defoaming the solution in a refrigerator at 4 ℃ for 8 hours, pre-freezing the solution in a refrigerator at-20 ℃ for 24 hours, freeze-drying the solution for 48 hours, and sterilizing the solution by using ethylene oxide to obtain the nano-silver antibacterial composite sponge based on different concentrations (0.0005%, 0.001% and 0.003%) of chitosan/polyvinyl alcohol.

Example 2 Nano-silver modified Chitosan-polyvinyl alcohol antibacterial composite sponge

The transmission electron microscope image of the antibacterial composite sponge with the nano-silver concentration of 0.0005% in example 1 is shown in fig. 1, and the diameter of the nano-particles is 50-80 nm. And then, taking CS-PVA as a blank group, and taking three groups of nano antibacterial composite sponges with nano silver concentration of 0.0005%, 0.001% and 0.003% as experimental groups to perform various performance analyses.

2.1 porosity

The porosity is an important index of the sponge body, and has certain influence on the water absorption performance, the drug release performance and other performances of the chitosan sponge. The prepared sponge has large volume and porosity, so the porosity of the sponge can be tested by adopting a volume method. Pure water was poured into the cylinder, and the scale corresponding to the liquid level was recorded as V1 (ml). The dried sponge was put into a graduated cylinder to completely immerse the sponge in pure water, and the scale corresponding to the liquid level was recorded as V2 (ml). The sponge was removed with forceps and the liquid level dropped due to the water-absorbing nature of the sponge voids, recorded as V3 (ml). Wherein V2-V3 represents the total volume of the sponge, namely the sum of the solid volume and the void volume; V1-V3 represent sponge void volume. The proportion of the sponge void volume to the total sponge volume is the porosity (P) of the sponge, and the calculation formula is as follows:

the porosity of the chitosan sponge was measured as shown in fig. 2. The porosity of the sponge material containing the nano-silver is 81 percent, the porosity of the chitosan/polyvinyl alcohol sponge is 70 percent, and the increase of the porosity is probably due to the fact that the water content is increased by adding the nano-silver antibacterial liquid. High porosity is a good property for wound dressings to absorb more exudate.

2.2 Water vapor Transmission Rate

A cylindrical plastic centrifuge tube slightly smaller than the diameter of the sponge is used as a test container, and the inner diameter d of the centrifuge tube is measured by a vernier caliper, so that the area of the centrifuge tube is S (pi d 2/4). After deionized water with the same volume is injected into the plastic centrifuge tube, the composite sponge is placed into the tube opening of the plastic centrifuge tube for sealing, the depth of each sponge inlet is ensured to be 10mm, and redundant samples are cut off by a knife parallel tube opening. The system was weighed with an electronic balance to have an initial mass m0 and then placed in an incubator at 37 ℃ and taken out after a lapse of time t and its mass mt was measured. Calculating the evaporation capacity of water penetrating through the sponge by measuring the mass change of the system to obtain the water vapor transmission rate MVTR:

avoiding the accumulation of exudate on the wound surface, the proper ratio of oxygen ingress and carbon dioxide egress is critical for wound healing. An ideal wound dressing should have good air permeability to ensure proliferation and growth of epidermal cells and fibroblasts. FIG. 3 is a graph of water vapor transmission rate relationship for composite sponge dressings of different contents. The sponge with higher nano-silver content has higher water vapor transmission rate, and the water vapor transmission rate of the sponge is consistent with the porosity trend. The crystallinity, the structure density and the like have great influence on the air permeability of the composite material, and the air permeability of the composite material is higher as the thickness is relatively thinner and the structure is looser, and the pore structure is more and the crystallinity is lower. In the whole view, the composite sponge has excellent air permeability and the water vapor transmission rate is more than 350gm-2 d-1.

2.3 degree of swelling and Water Retention

Characterization was performed by measuring the mass change in PBS buffer. The initial mass was measured as m1, soaked in PBS buffer, samples were taken at different times, excess liquid on the surface was wiped off with filter paper, and the mass was weighed as m 2. After weighing, equal amounts of PBS solution were supplemented until the end of the test. The calculation formula of the swelling degree is as follows:

and (3) soaking the sample in pure water for 24 hours until the sample reaches a saturated state, weighing the sample to be m3, taking out the sample at different times, wiping redundant liquid on the surface by using filter paper, weighing and recording the mass to be m 4. The calculation formula of the water retention rate is as follows:

to prevent wound infection and promote rapid wound healing, the wound should be in a moist, sterile environment. Therefore, an effective antimicrobial dressing needs to have good water absorption and moisture retention capabilities. The porous network structure of the composite sponge endows the composite sponge with excellent swelling performance. This experiment investigated the effect of swelling properties of sponges of different contents. FIG. 4 compares 4 curves, and all sponges show the same change trend, absorb water rapidly within 10mins, expand in volume, and then have the swelling ratio kept basically unchanged within 150 mins. The rapid imbibition capability of the composite sponge is mainly due to the capillary action generated by the developed pore structure of the composite sponge. In addition, the exposed free hydrophilic group (amino and hydroxyl) of the chitosan is hydrogen bonded with water molecules, and can also play a role in water absorption. The composite sponge has strong quick liquid absorption capacity and high swelling rate, and is favorable for absorbing a large amount of exudates. The chitosan/polyvinyl alcohol sponge has good moisture retention performance, and the water retention rate gradually decreases with the increase of the concentration of nano silver as shown in figure 5, probably because the aggregation of nano particles damages the network structure of the composite material.

2.4 mechanical Property testing

The composite sponge sample was first cut into 50X 20X 5mm standard samples and then placed in a universal force tester for tensile testing. The test parameters are: the load was 50N and the stretching rate was constant at 5 mm/min. Each sample was repeated six times.

In practical applications, the dressing is used to cover a wound surface for a long period of time. In order to meet the requirements of normal use, the dressing has good mechanical properties so as to reduce the limitation in use. In order to verify the influence of the nano-silver on the mechanical properties of the sample, the tensile properties of the composite sponge were tested. The mechanical properties are characterized by Young's modulus, tensile strength and elongation at break for the four samples as shown in Table 1. The tensile strength of the CS-PVA is 1.42 +/-0.66 MPa, and the elongation at break is 25.33 +/-1.37%. Compared with CS-PVA, the tensile strength and the elongation at break of the CS-PVA/Ag are both larger than those of the CS-PVA. The performance of the silver-containing composites was compared. With the increase of the nano silver concentration, the tensile strength is increased and then reduced. The initial increase may be due to the uniform dispersion of nanosilver in the polymer, increasing the tensile strength of the composite sponge. The subsequent decrease may be due to the increase of the nano silver concentration, thereby causing the nano silver to be easily polymerized, and the aggregated nano silver hinders the formation of the chitosan network structure, thereby reducing the tensile property and fluidity of the sample.

Table 1.Tensile properties of CS-PVA,CS-PVA/0.005％Ag,CS- PVA/0.01％Ag and CS-PVA/0.03％Ag.All values are expressed as the mean±SD for each group(n＝5)

2.5 in vitro degradation experiments

1mg/ml lysozyme PBS solution was used as the culture solution. After weighing the sample (W1), the sample was completely immersed in 1mg/ml of the culture medium and was degraded at a constant temperature of 37 ℃. And taking out the mixture at 2d, 5d, 10d, 15d and 20d respectively, freeze-drying and weighing (W2). The degradation kinetics curves are plotted with time t as abscissa and the mass residual ratio (W2/W1) as ordinate.

The enzymatic degradation characteristics of the composite sponges were studied by placing them in a 37 ℃ solution containing lysozyme. The glycosidic bond in chitosan is easily degraded by lysozyme. The percent degradation of the composite sponge as a function of time is shown in figure 6. Compared with the chitosan contrast, the degradation rate of the nano-silver-containing composite sponge is improved. The higher degradation rate can be attributed to the relatively higher swelling rate and porosity of the nanocomposite sponge, which allows the N-acetylglucosamine groups to be better degraded by lysozyme.

2.6 drug Release

Soaking composite sponges with different silver contents and the same mass in a PBS solution, and culturing in a constant-temperature shaking table at 37 ℃. At the measurement point, 2ml of the release solution was aspirated into the cuvette using a pipette gun while an equal amount of fresh PBS solution was supplied, keeping the total volume of the system constant. Measuring the absorbance of the release solution at 430nm with an ultraviolet spectrophotometer (PBS solution as blank control)

FIG. 7 shows that the drug release rate decreases with the increase of nano-silver content, from 88% for CS-PVA/0.0005% Ag to 81% for CS-PVA/0.001% Ag, and then to 76% for CS-PVA/0.0005% Ag. This is probably because the nano silver is bound to the chitosan/polyvinyl alcohol sponge matrix more firmly and is difficult to release, and the more the nano silver is, the more the binding part is, so that the cumulative release rate is reduced. Within the first 2h, the drug release rate is increased sharply and then gradually slowed down; after 5h, the cumulative drug release rate is basically stable, and the early burst release comes from the rapid dissolution of the drug.

2.7 antibacterial Properties

The antibacterial performance of the composite sponge on staphylococcus aureus and escherichia coli is researched, and an antibacterial experiment is carried out by two methods.

And (4) adopting a bacteriostatic zone test method. Putting the silver-containing sponges with different concentrations into a PBS solution to be soaked for 24 hours to obtain a leaching solution. Preparing escherichia coli and staphylococcus aureus into 106CFU/mL bacterial suspension, uniformly smearing 0.1mL bacterial liquid on the surface of a culture medium plate, clamping a sterilized 20mm filter paper piece by using forceps, and fully dipping the leaching liquor of each sample to be attached to the surface of the culture medium. Then placing the culture dish into an incubator at 37 ℃ for inverted culture for 24 hours, taking out and measuring the size of each inhibition zone.

Equal amounts of different concentrations of samples were placed in tubes with 10ml of LB medium and a blank was set. Staphylococcus aureus and Escherichia coli were added separately to tubes and diluted to 106 CFU/ml. The tubes were then incubated in an incubator at 37 ℃ for 6, 12, 24h, OD measured at 630nm, and the turbidity of the bacterial suspension visually analyzed. As can be seen from fig. 8, the experimental group containing nano-silver has a significantly better sterilization effect than the control group, and the nano-silver provides the material with excellent performance of potent sterilization and broad-spectrum sterilization. The material is soaked in LB culture medium, and the nano silver is released slowly through the compact and open sponge pore canal and acts on the bacteria liquid continuously. Along with the increase of the soaking time of the material in the aqueous solution, the release amount of the nano silver is increased until the nano silver in the solution reaches a certain concentration, and the effective inhibition and even killing effect on bacterial liquid can be generated. The antibacterial principle of nano silver is generally considered to be that nano silver penetrates cell walls and enters bacteria, reacts with sulfhydryl groups of cell synthetases to destroy the activity of the cell synthetases, and the bacteria lose the capability of division and proliferation and die. The nano silver is dissociated from the dead bacteria, and thus, the sterilization is repeatedly performed.

2.8 cytotoxicity

Firstly, placing the compound sponge in an RPMI-1640 culture medium for culturing for 24h to obtain a leaching liquor. After the cells were cultured in 96-well plates for 12 hours, the culture medium was removed, and the extract and 10% fetal bovine serum were added. After 24h and 48h incubation, the liquid was removed and MTT solution was added and incubation continued for 4 h. Then terminating the culture, removing the MTT culture solution, adding DMSO, and placing on a shaker

Oscillating at low speed for 10min to dissolve the crystal completely, and measuring the light absorption value at 490nm with enzyme linked immunosorbent detector.

Fig. 9 shows the growth of endothelial cells on the blanks, control sponges, and experimental sponges containing nanoparticles. The absorbance value reflects the relative amount of cell growth, with higher values indicating better cell proliferation, less toxicity or better enhancement of the material to cell growth.

As can be seen from fig. 9, the absorbance values of the blank, the control and the experimental group are increased with time, and the CS-PVA control group proliferates faster than the blank control group, because chitosan is a natural polymer material having excellent biological activity, and can promote wound healing and skin tissue repair. The blank, CS-PVA and nanoparticle-containing loaded dressings did not differ significantly by significant difference analysis. This demonstrates that the nanoparticle-containing sponge is not significantly toxic to endothelial cells and has the effect of promoting the growth of the cells. The low-concentration nano-particles have no obvious cytotoxicity and are nontoxic materials with good biocompatibility.

Conclusion

The chitosan/polyvinyl alcohol sponge dressing is prepared by a freeze drying method, silver nitrate is reduced by tannic acid to obtain nano silver, bovine serum albumin is used as a stabilizer, and nano particles are prepared for antibiosis. The diameter of the nano particles is 50-80nm as shown in a transmission electron microscope picture. The composite sponge added with the antibacterial agent has good antibacterial effect, and because the nano-silver resists, the drug resistance is not easy to generate, the bacteria with the drug resistance can be effectively killed. The antibacterial performance of the nano-particles is 5-10 times stronger than that of nano-silver under the same concentration. The sponge dressing containing the nano particles has better mechanical property than chitosan/polyvinyl alcohol sponge, has good water absorption and water retention, and can keep the wound surface in a humid environment for a long time. The scanning electron microscope image shows that the composite sponge has three-dimensional reticular porosity, and the pore diameter is about 100-250 μm. In-vitro cytotoxicity experiments prove that the composite sponge dressing has good biocompatibility. The prepared composite sponge dressing meets the requirements of ideal dressing on exudate absorption, moisture retention, good mechanical property, antibiosis and cell compatibility. Therefore, the CS-PVA/nAg dressing is an ideal dressing and has potential application prospect in the management and healing aspects of low-to-moderate exudation wounds and surgical wounds.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. An antibacterial composition, which is characterized by comprising chitosan, polyvinyl alcohol, silver nitrate, glutaraldehyde, glycerol, tannic acid, curcumin, ferric chloride, dimethyl sulfoxide and bovine serum albumin, wherein the mass part ratio of the chitosan to the polyvinyl alcohol to the silver nitrate is 2-6: 5-15: 0.001-0.006.

2. The antimicrobial composition of claim 1, wherein the ratio of the chitosan, the polyvinyl alcohol and the silver nitrate in parts by mass is 2: 5: 0.001.

3. use of the antibacterial composition of claim 1 or 2 for preparing an antibacterial composite sponge.

4. Use of the antimicrobial composition of claim 1 or 2 to increase the porosity of an antimicrobial composite sponge.

5. A preparation method of nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge is characterized by comprising the following steps,

6. The method according to claim 5, wherein the chitosan acetic acid solution is 0.02g/ml, and the polyvinyl alcohol solution is 0.05 g/ml.

7. The method according to claim 6, wherein the mixing volume ratio of the chitosan acetic acid solution and the polyvinyl alcohol solution is 0.5-2: 1.

8. the method according to claim 5, wherein the mass ratio of curcumin, tannic acid, ferric chloride and bovine serum albumin is 1: 10: 2: 20.

9. the method according to claim 5, wherein the volume ratio of the chitosan polyvinyl alcohol solution to the antibacterial solution is 5-10: 1.

10. The preparation method of claim 5, wherein the temperature for standing and defoaming is 0-4 ℃ and the time is 6-12 h; the freeze drying time is 36-48 h.