Quaternary ammonium salt polyvinyl alcohol with adjustable adhesion, preparation method and application

Abstract

The present invention relates to the technical field of biomedical materials, and in particular to a quaternary ammonium salt polyvinyl alcohol with adjustable adhesion, a preparation method and an application. The quaternary ammonium salt polyvinyl alcohol with adjustable adhesion of the present invention has a structural formula shown in formula (I). The preparation method of the quaternary ammonium salt polyvinyl alcohol of the present invention is: PVA is dissolved in an organic solvent, an activator CDI is added for activation, DEEDA is subsequently added for reaction, and PVA-DEEDA is obtained after impurity removal, precipitation, purification and drying; PVA-DEEDA is dissolved in an organic solvent, and then DOP-CH2Br is added for heating reaction, and PVA-DEEDA-DOP is obtained after precipitation, purification and drying. The quaternary ammonium salt polyvinyl alcohol of the present invention has both temperature, pH response and tissue adhesion properties, and belongs to a quaternary ammonium salt polymer antibacterial agent at the same time, and has the characteristics of superior antibacterial performance, safety and non-toxicity, and stable antibacterial performance, and can achieve in situ killing of bacteria.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical materials, and in particular to a quaternary ammonium salt polyvinyl alcohol with adjustable adhesion, a preparation method and an application thereof. Background Art

[0002] Clinically, there are casualties every year due to massive blood loss caused by failure to close wounds in time. At present, the commonly used wound treatment method in clinical practice is the traditional suturing method, which takes a long time to treat and is difficult to completely close for wounds with large wound surfaces. Compared with sutures, tissue adhesives, as a substitute for surgical sutures, are easy to use, have strong coverage, and do not need to be removed during further treatment, thus attracting much attention.

[0003] In the process of exploring excellent bioadhesives, researchers found that some mussel proteins have strong adhesion and can adhere quickly. They still maintain excellent performance in a humid environment and are very suitable for adhesion in vivo and in vitro. Among them, L-3,4-dihydroxyphenylalanine (L-DOPA) is one of its key substances. The catechol structure has excellent adhesion ability under the combined action of complexation, hydrogen bonding and chemical bonding. At present, the overall research strategy of biomimetic mussel protein adhesives is to introduce catechol units into the end groups or side chains of polymers to achieve tissue adhesion. The materials obtained by these methods can achieve adhesion and self-healing properties in a humid environment. However, due to its low mechanical properties and slow onset time, it is impossible to achieve on-demand regulation of adhesion, which is still far from the requirements of clinical applications.

[0004] In addition, the number of deaths caused by bacterial, viral and fungal infections each year accounts for a quarter of the global death toll. Since microorganisms are everywhere and can be transmitted through air, water and food, controlling and preventing microbial infections is also a major challenge in wound treatment. Existing low-molecular-weight antimicrobial agents generally have the problem of penetrating from the polymer matrix and are highly toxic to organisms. Therefore, a biopharmaceutical material that can take into account both tissue adhesion and safe antibacterial properties is an existing problem that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a quaternary ammonium salt polyvinyl alcohol with adjustable adhesion, a preparation method and application, so as to solve the problems of poor mechanical properties and slow onset of action of existing tissue adhesives and high toxicity of existing low molecular weight antibacterial agents to organisms.

[0006] To achieve the above object, the present invention adopts the following technical scheme: a quaternary ammonium salt polyvinyl alcohol with adjustable adhesion, the structural formula of the quaternary ammonium salt polyvinyl alcohol is shown in formula (I):

[0007] Formula (I),

[0008] In formula (I), m1, n and m2 represent the degree of polymerization of each repeating unit.

[0009] Furthermore, in the formula (I), m1+n+m2=1932~2818.

[0010] A method for preparing quaternary ammonium salt polyvinyl alcohol comprises the following steps:

[0011] S1, dissolving polyvinyl alcohol in an organic solvent, adding an activator N,N′-carbonyldiimidazole for activation, then adding N,N-diethylethylenediamine for reaction, removing impurities, precipitating, purifying, and drying to obtain diethylethylenediamine-modified polyvinyl alcohol;

[0012] S2, dissolving dopamine hydrochloride in a solvent, adding triethylamine to neutralize the hydrochloric acid therein, then adding 4-bromomethylbenzoic acid, reacting in the presence of a condensing agent, rotary evaporating the product, and freeze-drying to obtain bromomethyldopamine;

[0013] S3, dissolving the polyvinyl alcohol modified with diethylethylenediamine obtained in S1 in an organic solvent, then adding bromomethyldopamine obtained in S2, heating for reaction, precipitation, purification, and drying to obtain quaternary ammonium salt polyvinyl alcohol with tissue adhesion.

[0014] Furthermore, in the S1, the weight average molecular weight of polyvinyl alcohol is 85000-124000; the organic solvent is dimethyl sulfoxide; the reaction temperature is 25° C., and the reaction time is 12-36 hours.

[0015] Furthermore, in the S1, the molar ratio of polyvinyl alcohol to the activator N,N′-carbonyldiimidazole is 1:0.3-0.6; the molar ratio of polyvinyl alcohol to N,N-diethylethylenediamine is 1:0.3-0.6.

[0016] Furthermore, in the S2, the solvent is a mixed solvent of tetrahydrofuran and water; the molar ratio of triethylamine to dopamine hydrochloride is 1-3:1; the molar ratio of 4-bromomethylbenzoic acid to dopamine hydrochloride is 0.6-1.5:1; the condensing agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole; the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to dopamine hydrochloride is 1-1.5:1; the molar ratio of 1-hydroxybenzotriazole to dopamine hydrochloride is 0.1-0.15:1; the reaction temperature is 25°C, and the reaction time is 12-36h.

[0017] Furthermore, in the S3, the organic solvent is dimethyl sulfoxide; the heating reaction temperature is 50-80° C., and the heating reaction time is 20-36 hours.

[0018] Furthermore, in the S3, the molar ratio of the polyvinyl alcohol modified with diethylethylenediamine to bromomethyldopamine is 1:0.02-0.15.

[0019] Furthermore, in the above-mentioned S1 and S3, precipitation refers to precipitation in acetone; purification refers to dissolving the precipitate with water and then dialyzing to obtain a purified product; and drying refers to freeze drying.

[0020] Application of quaternized polyvinyl alcohol as adhesive and antimicrobial agent.

[0021] Beneficial effects of the present invention:

[0022] The synthetic raw materials of the present invention are cheap and readily available, the synthetic reaction conditions are mild, the reaction time is short, the process operation is simple, and the production cost is low; the quaternary ammonium salt polyvinyl alcohol of the present invention has dual responses to temperature and pH (including physiological environment temperature), and the phase change temperature can be adjusted by controlling the ratio; at the same time, it has excellent adhesion properties, and can continue to sterilize while tightly adhering to biological tissues, and is a good biological functional material; the quaternary ammonium salt polyvinyl alcohol of the present invention has excellent antibacterial properties, fast sterilization rate, and high antibacterial efficiency; it can avoid the problem of low molecular weight antibacterial agents penetrating from the polymer matrix, and has low toxicity to organisms; it exhibits high antibacterial activity at low concentrations, and can achieve adhesion to tissues and in situ antibacterial; the quaternary ammonium salt polyvinyl alcohol of the present invention has good water solubility, biocompatibility and biodegradability, and has excellent mechanical properties such as spinning, film formation and gel formation. When used as an antibacterial agent, no organic solvent does need to be added to promote solubilization, and overall coverage of wounds and lasting antibacterial can be achieved, and it has considerable application prospects.

[0023] Figure 1 is the chemical structural formula of the quaternary ammonium salt polyvinyl alcohol (PVA-DEEDA-DOP) obtained in Example 1 of the present invention;

[0024] Figure 2 : are the NMR spectra of polyvinyl alcohol (PVA), modified polyvinyl alcohol (PVA-DEEDA) and quaternary ammonium salt polyvinyl alcohol (PVA-DEEDA-DOP) used in Example 1 of the present invention;

[0025] Figure 3 This is a graph showing the results of a PVA-DEEDA-DOP cytotoxicity experiment obtained in Example 1 of the present invention;

[0026] Figure 4 This is a graph showing the antibacterial test results of PVA-DEEDA-DOP obtained in Example 1 of the present invention;

[0027] Figure 5This is a graph showing the adhesion results of PVA-DEEDA-DOP obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] The present invention first uses polyvinyl alcohol (PVA) as the main chain, uses N,N′-carbonyldiimidazole (CDI) to activate PVA to form an intermediate, and then uses a nucleophilic substance N,N-diethylethylenediamine (DEEDA) with a primary amine to modify it to obtain polyvinyl alcohol with a hydrophilic amide (-C0-NH-) and a hydrophobic ethylamine group; these two parts alternately control the properties of the polymer in an aqueous solution, so that it has temperature and pH responses, and the reaction is as follows:

[0030]

[0031] Then, dopamine hydrochloride is dissolved in a solvent, triethylamine (TEA) is added to neutralize the hydrochloric acid therein, and then 4-bromomethylbenzoic acid is added to react in the presence of a condensing agent, wherein the condensing agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 1-hydroxybenzotriazole (HOBt); the product is rotary evaporated and freeze-dried to obtain bromomethyl dopamine (DOP-CH2Br), and the reaction is as follows:

[0032]

[0033] Finally, the temperature- and pH-responsive quaternary ammonium salt polyvinyl alcohol with tissue adhesion was prepared by further quaternization reaction of the tertiary ethylamine group with the dopamine molecule (DOP-CH2Br) with bromomethyl group. The reaction is as follows:

[0034]

[0035] Dopamine (DOP) molecules have adhesion to various interfaces, and the quaternary ammonium salt polyvinyl alcohol can effectively control the performance by adjusting the percentage content of the quaternary ammonium salt and the DOP adhesion functional group.

[0036] Example 1

[0037] S1. Preparation of PVA-DEEDA

[0038] Dissolve polyvinyl alcohol (5.0 g, hydroxyl molar amount is 0.12 mol) in 100 mL dimethyl sulfoxide (DMSO) and stir to dissolve at 90°C; after complete dissolution, cool to room temperature, add N,N′-carbonyldiimidazole (CDI) (7.8 g, 0.048 mol) to the above solution for activation for 3 hours, then slowly add N,N-diethylethylenediamine (DEEDA) (6.7 mL, 0.048 mol) to the above solution and react at 25°C for 20 hours; after the reaction is completed, precipitate in acetone, dissolve the precipitate in deionized water, dialyze for 3 days, and freeze-dry to obtain modified polyvinyl alcohol; the weight average molecular weight of polyvinyl alcohol is preferably 85000~124000.

[0039] S2. Preparation of DOP-CH2Br

[0040] Dopamine hydrochloride (760 mg, 4 mmol) was dissolved in 1.5 mL of deionized water, and triethylamine (TEA) (600 mg, 6 mmol) was added and stirred until completely dissolved; 4-bromomethylbenzoic acid (860 mg, 4 mmol) was dissolved in 4 mL of tetrahydrofuran (THF), and the two were mixed, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC () 998 mg, 5.2 mmol) and 1-hydroxybenzotriazole (HOBt) (54 mg, 0.4 mmol) were added, and the reaction was stirred at 25 ° C for 24 hours; after the reaction was completed, rotary evaporation and freeze-drying were performed to obtain DOP-CH2Br with a content of 55%.

[0041] S3. Preparation of PVA-DEEDA-DOP

[0042] PVA-DEEDA (400 mg, 7.12 mmol) obtained in S1 was dissolved in 10 mL DMSO and stirred until completely dissolved. DOP-CH2Br (272 mg, 0.702 mmol) was then added and heated at 70°C for 24 h. The precipitate was precipitated with acetone and dissolved in deionized water. The precipitate was dialyzed for 3 days and freeze-dried to obtain PVA-DEEDA-DOP.

[0043] The PVA used in this example and the prepared PVA-DEEDA and PVA-DEEDA-DOP were subjected to NMR testing. The results are shown in Figure 2 .

[0044] The cytotoxicity of PVA-DEEDA-DOP prepared in this example was characterized.

[0045] Mouse fibroblasts (L929 cells) were selected for the experiment; L929 cells were cultured at 5×10 3 The cells were seeded at a density of 1:1 in a 96-well plate and incubated at 5% CO2, 37 oC for 24 h, discard the culture medium, add culture medium solutions containing different concentrations of PVA-DEEDA-DOP and continue to culture for 48 h, remove the culture medium, rinse the cells three times with PBS, add 100 μL of CCK-8 working solution to each well, and culture the cells for further 1 h. Use a microplate reader to measure the absorbance of each well at 450 nm and calculate the cell survival rate. The results are shown in Figure 3 The results show that the polyvinyl alcohol quaternary ammonium salt material prepared in this example has good biocompatibility.

[0046] The antibacterial properties of PVA-DDEDA-DOP prepared in this example were studied.

[0047] All bacterial experimental consumables were sterilized at high temperature and high pressure to prevent foreign bacteria from affecting the experimental results; LB culture medium and nutrient agar were dissolved in deionized water according to the instructions and then sterilized in an autoclave; after sterilization, the culture medium was stored in a 4°C refrigerator; LB nutrient agar was poured into a disposable culture dish and spread on the plate, and after cooling and solidification, it was collected and stored in a 4°C refrigerator.

[0048] In bacterial culture, first use an inoculation needle to pick up a small amount of Staphylococcus aureus (ATCC29213) and Escherichia coli (ATCC 15224) and add them to 15mL LE medium, and place them in a shaker at 37°C (220rpm) until the bacteria reach a medium concentration. Dilute the bacterial solution in a gradient and apply it to the agar plate; place the agar plate in a 37°C mold incubator overnight and incubate until colonies grow on the surface of the agar plate; select an agar plate with an appropriate colony concentration, use an inoculation needle to pick up a single colony, place it in a 15mL shaking tube, add 3~5mL fresh LB medium, and place it in a shaker at 37°C (220rpm) for 5h to make the bacterial concentration reach a medium level.

[0049] Place PVA-DEEDA-DOP solutions of different concentrations in 1.5 mL centrifuge tubes and add 200 μL of 10% diluted solution to each well. 6 cfu / mL of bacterial solution was cultured at 37°C in a shaker at 150 rpm for 2 hours; after 2 hours, the bacterial solution was diluted gradiently, and 10 μL was taken and applied to the agar culture plate, which was then cultured overnight in a mold incubator. When the colony size was appropriate, an agar culture plate with an appropriate concentration gradient was selected for bacterial counting. The results are shown in Figure 4 ; The results show that the material has good antibacterial properties against both Gram-positive and Gram-negative bacteria.

[0050] The adhesion of PVA-DEEDA-DOP prepared in this example was characterized.

[0051] Fresh pigskin was selected as the material for the lap shear test; the pigskin was cut into a rectangle of 60mm×150mm, and then 50mg PVA-DEEDA-DOP was placed between two pieces of fresh pigskin, with a contact area of ​​60mm×50mm; then, the two pieces of pigskin were stretched in opposite directions at a rate of 1mm / min using a DMA Q800 mechanical analyzer, and the load, displacement and other data were recorded until the material was completely detached from the skin. The adhesion effect was shown in Figure 2. Figure 5 ; This result shows that the material skin has good adhesion properties.

[0052] Example 2

[0053] S1. Preparation of PVA-DEEDA

[0054] Dissolve polyvinyl alcohol (5.0 g, hydroxyl molar amount is 0.12 mol) in 100 mL DMSO and stir to dissolve at 90°C; after complete dissolution, cool to room temperature, add CDI (9.2 g, 0.06 mol) to the above solution for activation for 3 hours, then slowly add DEEDA (8 mL, 0.06 mol) to the above solution and react at 25°C for 20 hours; after the reaction is completed, precipitate in acetone, dissolve the precipitate in deionized water, dialyze for 3 days, and freeze-dry to obtain modified polyvinyl alcohol; the weight average molecular weight of the polyvinyl alcohol is preferably 85000~124000.

[0055] S2. Preparation of DOP-CH2Br

[0056] Dopamine hydrochloride (760 mg, 4 mmol) was dissolved in 1.5 mL of deionized water, TEA (600 mg, 6 mmol) was added, and the mixture was stirred until completely dissolved. 4-Bromomethylbenzoic acid (860 mg, 4 mmol) was dissolved in 4 mL of tetrahydrofuran, and the two were mixed. EDC (998 mg, 5.2 mmol) and HOBt (54 mg, 0.4 mmol) were added, and the mixture was stirred at 25 ° C for 24 h. After the reaction was completed, the mixture was rotary evaporated and freeze-dried to obtain DOP-CH2Br with a content of 55%.

[0057] S3. Preparation of PVA-DEEDA-DOP

[0058] The PVA-DEEDA (400 mg, 7.12 mmol) obtained in S1 was dissolved in 12 mL DMSO and stirred until completely dissolved. DOP-CH2Br (272 mg, 0.702 mmol) was then added and heated at 70°C for 24 h. The precipitate was precipitated with acetone and dissolved in deionized water. The precipitate was dialyzed for 3 days and freeze-dried to obtain PVA-DEEDA-DOP.

[0059] Example 3

[0060] S1. Preparation of PVA-DEEDA

[0061] Dissolve polyvinyl alcohol (5.0 g, hydroxyl molar amount is 0.12 mol) in 100 mL DMSO and stir to dissolve at 90°C; after complete dissolution, cool to room temperature, add CDI (11.7 g, 0.072 mol) to the above solution for activation for 3 hours, then slowly add DEEDA (10 mL, 0.072 mol) to the above solution and react at 25°C for 20 hours; after the reaction is completed, precipitate in acetone, dissolve the precipitate in deionized water, dialyze for 3 days, and freeze-dry to obtain modified polyvinyl alcohol; the weight average molecular weight of polyvinyl alcohol is preferably 85000~124000.

[0062] S2. Preparation of DOP-CH2Br

[0063] Dopamine hydrochloride (760 mg, 4 mmol) was dissolved in 1.5 mL of deionized water, TEA (600 mg, 6 mmol) was added, and the mixture was stirred until completely dissolved; 4-bromomethylbenzoic acid (860 mg, 4 mmol) was dissolved in 4 mL of tetrahydrofuran, the two were mixed, EDC (998 mg, 5.2 mmol) and HOBt (54 mg, 0.4 mmol) were added, and the mixture was stirred at 25 ° C for 24 h; after the reaction was completed, the mixture was rotary evaporated and freeze-dried to obtain DOP-CH2Br with a content of 55%.

[0064] S3. Preparation of PVA-DEEDA-DOP

[0065] PVA-DEEDA (400 mg, 7.12 mmol) obtained in S1 was dissolved in 12 mL DMSO and stirred until completely dissolved. DOP-CH2Br (272 mg, 0.702 mmol) was then added and heated at 70°C for 24 h. The precipitate was precipitated with acetone and dissolved in deionized water. The precipitate was dialyzed for 3 days and freeze-dried to obtain PVA-DEEDA-DOP.

[0066] Example 4

[0067] S1. Preparation of PVA-DEEDA

[0068] Dissolve polyvinyl alcohol (5.0 g, hydroxyl molar amount is 0.12 mol) in 100 mL DMSO and stir to dissolve at 90°C; after complete dissolution, cool to room temperature, add CDI (9.2 g, 0.06 mol) to the above solution for activation for 3 hours, then slowly add DEEDA (8 mL, 0.06 mol) to the above solution and react at 25°C for 20 hours; after the reaction is completed, precipitate in acetone, dissolve the precipitate in deionized water, dialyze for 3 days, and freeze-dry to obtain modified polyvinyl alcohol; the weight average molecular weight of the polyvinyl alcohol is preferably 85000~124000.

[0069] S2. Preparation of DOP-CH2Br

[0070] Dopamine hydrochloride (760 mg, 4 mmol) was dissolved in 1.5 mL of deionized water, TEA (600 mg, 6 mmol) was added, and the mixture was stirred until completely dissolved. 4-Bromomethylbenzoic acid (860 mg, 4 mmol) was dissolved in 4 mL of tetrahydrofuran, the two were mixed, EDC (998 mg, 5.2 mmol) and HOBt (54 mg, 0.4 mmol) were added, and the mixture was stirred at 25 ° C for 24 h. After the reaction was completed, the mixture was rotary evaporated and freeze-dried to obtain DOP-CH2Br with a content of 55%.

[0071] S3. Preparation of PVA-DEEDA-DOP

[0072] PVA-DEEDA (600 mg, 10.68 mmol) obtained in S1 was dissolved in 12 mL DMSO and stirred until completely dissolved. DOP-CH2Br (600 mg, 1.55 mmol) was then added and heated at 70°C for 24 h. The precipitate was precipitated with acetone and dissolved in deionized water. The precipitate was dialyzed for 3 days and freeze-dried to obtain PVA-DEEDA-DOP.

[0073] Example 5

[0074] S1. Preparation of PVA-DEEDA

[0075] Polyvinyl alcohol (5.0 g, hydroxyl molar amount is 0.12 mol) is dissolved in 100 mL DMSO and stirred at 90°C to dissolve; after complete dissolution, it is cooled to room temperature, CDI (9.2 g, 0.06 mol) is added to the above solution for activation for 3 hours, and then DEEDA (8 mL, 0.06 mol) is slowly added to the above solution, and reacted at 25°C for 20 hours; after the reaction is completed, it is precipitated in acetone, and the precipitate is dissolved in deionized water, dialyzed for 3 days, and freeze-dried to obtain modified polyvinyl alcohol; the weight average molecular weight of the polyvinyl alcohol is preferably 85000~124000.

[0076] S2. Preparation of DOP-CH2Br

[0077] Dopamine hydrochloride (760 mg, 4 mmol) was dissolved in 1.5 mL of deionized water, TEA (600 mg, 6 mmol) was added, and the mixture was stirred until completely dissolved. 4-Bromomethylbenzoic acid (860 mg, 4 mmol) was dissolved in 4 mL of tetrahydrofuran, the two were mixed, EDC (998 mg, 5.2 mmol) and HOBt (54 mg, 0.4 mmol) were added, and the mixture was stirred at 25 ° C for 24 h. After the reaction was completed, the mixture was rotary evaporated and freeze-dried to obtain DOP-CH2Br with a content of 55%.

[0078] S3. Preparation of PVA-DEEDA-DOP

[0079] The PVA-DEEDA (600 mg, 10.68 mmol) obtained in S1 was dissolved in 12 mL DMSO and stirred until completely dissolved. DOP-CH2Br (400 mg, 1.03 mmol) was then added and heated at 70°C for 24 h. The precipitate was precipitated with acetone and dissolved in deionized water. The precipitate was dialyzed for 3 days and freeze-dried to obtain PVA-DEEDA-DOP.

[0080] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A quaternary ammonium salt polyvinyl alcohol with adjustable adhesion, characterized in that: The structural formula of the quaternary ammonium salt polyvinyl alcohol is shown in formula (I): Formula (I), In formula (I), m1, n and m2 represent the degree of polymerization of each repeating unit.

2. The quaternary ammonium salt polyvinyl alcohol with adjustable adhesion according to claim 1, characterized in that: In the formula (I), m1+n+m2=1932~2818.

3. The method for preparing quaternary ammonium salt polyvinyl alcohol according to claim 1, characterized in that: The following steps are involved: S1, dissolving polyvinyl alcohol in an organic solvent, adding an activator N,N′-carbonyldiimidazole for activation, then adding N,N-diethylethylenediamine for reaction, removing impurities, precipitating, purifying, and drying to obtain diethylethylenediamine-modified polyvinyl alcohol; S2, dissolving dopamine hydrochloride in a solvent, adding triethylamine to neutralize the hydrochloric acid therein, then adding 4-bromomethylbenzoic acid, reacting in the presence of a condensing agent, rotary evaporating the product, and freeze-drying to obtain bromomethyldopamine; S3, dissolving the polyvinyl alcohol modified with diethylethylenediamine obtained in S1 in an organic solvent, then adding bromomethyldopamine obtained in S2, heating for reaction, precipitation, purification, and drying to obtain quaternary ammonium salt polyvinyl alcohol with adjustable adhesion.

4. The method for preparing quaternary ammonium salt polyvinyl alcohol according to claim 3, characterized in that: In the S1, the weight average molecular weight of polyvinyl alcohol is 85000-124000; the organic solvent is dimethyl sulfoxide; the reaction temperature is 25° C., and the reaction time is 12-36 hours.

5. The method for preparing quaternary ammonium salt polyvinyl alcohol according to claim 3, characterized in that: In the S1, the molar ratio of polyvinyl alcohol to the activator N,N′-carbonyldiimidazole is 1:0.3-0.6; the molar ratio of polyvinyl alcohol to N,N-diethylethylenediamine is 1:0.3-0.

6.

6. The method for preparing quaternary ammonium salt polyvinyl alcohol according to claim 3, characterized in that: In the S2, the solvent is a mixed solvent of tetrahydrofuran and water; the molar ratio of triethylamine to dopamine hydrochloride is 1-3:1; the molar ratio of 4-bromomethylbenzoic acid to dopamine hydrochloride is 0.6-1.5:1; the condensing agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole; the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to dopamine hydrochloride is 1-1.5:1; the molar ratio of 1-hydroxybenzotriazole to dopamine hydrochloride is 0.1-0.15:1; the reaction temperature is 25°C, and the reaction time is 12-36h.

7. The method for preparing quaternary ammonium salt polyvinyl alcohol according to claim 3, characterized in that: In the S3, the organic solvent is dimethyl sulfoxide; the heating reaction temperature is 50-80° C., and the heating reaction time is 20-36 hours.

8. The method for preparing quaternary ammonium salt polyvinyl alcohol according to claim 3, characterized in that: In the S3, the molar ratio of the polyvinyl alcohol modified with diethylethylenediamine to bromomethyldopamine is 1:0.02-0.

15.

9. The method for preparing quaternary ammonium salt polyvinyl alcohol according to claim 3, characterized in that: In the above-mentioned S1 and S3, precipitation refers to precipitation in acetone; purification refers to dissolving the precipitate with water and then dialyzing to obtain a purified product; and drying refers to freeze drying.

10. Use of the quaternized polyvinyl alcohol according to claim 1 as an adhesive and antibacterial agent.

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