A coating material with synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions and its preparation method

Abstract

The present invention discloses a coating material with synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions and its preparation method. A multi-step impregnation method is used, including: ① oxidizing the surface of the substrate material; ② immersing the substrate in DA-Tris buffer solution to form a first layer of PDA coating; ③ immersing the substrate in Ag + The researchers then immersed the AgNPs-GO dispersion in a 4-layer AgNPs-GO coating; 4 immersed the AgNPs-GO coating in a DA-Tris buffer solution to form a 3-layer PDA coating; 5 then alternately immersed the above materials in a sodium polyphosphate solution and a quaternized chitosan (QCs) solution to form a 4-layer QCs coating; 6 finally, through a ring-opening reaction, surface chemical grafting of a copolymer of glycidyl acrylate and zwitterions (PGS) was performed to obtain a PGS / QCs / PDA / AgNPs-GO / PDA coating. This coating combines the functions of AgNPs release and sterilization, QCs contact sterilization, PDA and GO photothermal sterilization, and zwitterion anti-protein adhesion (anti-fouling) into one material. The PDA intermediate layer ensures the universality of the technology and is expected to be applied to the surface and interface antibacterial and anti-fouling of various materials.

Description

Technical Field

[0001] The present invention relates to the technical field of antibacterial surfaces, and in particular to a coating material based on AgNPs, QCs and zwitterions with synergistic antibacterial and antifouling functions and a preparation method thereof. Background Art

[0002] With the rapid development of clinical technology, the use of clinical implants has increased, and the number of implant-related complications has also gradually increased. Implant-associated infection (IAI) is a difficult problem faced by clinical practice. Once it occurs, a second operation is often required to remove the implant. This process can cause great harm to the patient and directly lead to the failure of the previous surgery. In addition, the cost of subsequent supportive treatment is high, the patient suffers greatly, and the prognosis is poor. The main methods for preventing implant-associated infection in clinical practice include strengthening aseptic operation and the use of prophylactic systemic antibiotics before and after surgery. However, the level of hospitals at all levels is uneven, the level of aseptic operation varies, and the postoperative infection rate in lower-level hospitals remains high; the use of prophylactic systemic antibiotics cannot achieve ideal local drug concentrations, resulting in poor results.

[0003] In recent years, a variety of clinically available implants with antimicrobial coatings have emerged. Conventional antimicrobial implants are coated with only antimicrobial ingredients, which can lead to a series of problems. While simple antibiotic coatings can kill most bacteria early on, the subsequent development of drug-resistant infections is difficult to overcome. Simple antimicrobial ingredients (such as silver coatings) have strong local cytotoxicity, causing in situ aseptic inflammation and inhibiting wound healing. Furthermore, the initial burst of drug release caused by simple coatings can shorten the duration of drug efficacy, resulting in poor antimicrobial efficacy later in life. Furthermore, these antimicrobial implants are ineffective against bacterial biofilm formation. Bacterial biofilms are membrane-like aggregates formed by bacteria adhering to surfaces and enveloping themselves in an extracellular matrix. These biofilms are highly resistant and invasive, making modern treatments ineffective. Preventing biofilm formation is currently the most effective treatment for biofilm infections. Once biofilm formation is inhibited, further application of antimicrobial active ingredients to kill free bacteria can synergistically achieve a significant anti-infection effect. To this end, the present invention designs a coating material with synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions, in which the surface zwitterion coating layer has a strong antibacterial adhesion effect, while AgNPs and QCs play a synergistic bactericidal effect, which is used to solve the increasingly serious problem of implant-related infection. Summary of the Invention

[0004] The purpose of the present invention is to provide a coating material with synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions and a preparation method thereof, in view of the shortcomings of the existing technology and combining the advantages of various materials and processes.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A coating material based on AgNPs, QCs and zwitterions with synergistic antibacterial and antifouling functions is disclosed. The material comprises a first layer of polydopamine (PDA) coating, a second layer of nanosilver-graphene oxide (AgNPs-GO) coating, a third layer of PDA coating, and a fourth layer of quaternized chitosan (QCs) coating with a PGS copolymer grafted on its surface, formed in sequence on a substrate using a multi-step impregnation method. The PGS / QCs / PDA / AgNPs-GO / PDA coating material is obtained. The PGS copolymer is prepared by copolymerization of zwitterionic sulfobetaine methacrylate (SBMA) and glycidyl acrylate (GMA).

[0007] The PGS / QCs / PDA / AgNPs-GO / PDA coating material was prepared using a multi-step impregnation method. The specific preparation steps include the following:

[0008] 1) After cleaning the base material, perform surface oxidation treatment on it according to the material characteristics;

[0009] 2) preparing a Tris-HCl solution of DA (pH = 8.5), immersing the substrate in the Tris-HCl solution of DA, and forming a first layer of PDA coating on the substrate surface through the self-polymerization reaction of DA;

[0010] 3) Prepare GO aqueous dispersion under ultrasound, vortex oscillation and ultra-high speed stirring conditions, then slowly add silver nitrate solution under light-proof and ultrasound conditions, and obtain Ag after ultra-high speed stirring. + -GO dispersion. The sample prepared in step 2) was immersed in the above Ag + -GO dispersion, PDA was used to achieve Ag under oscillation conditions. + After sufficient reduction, a second layer of AgNPs-GO coating structure is formed on the surface of the first layer of PDA coating;

[0011] 4) The sample prepared in step 3) was added to the Tris-HCl solution (pH=8.5) of DA for in-situ self-polymerization to form a third layer of PDA coating structure on the surface of the second layer of AgNPs-GO coating.

[0012] 5) The sample in step 4) is subjected to self-assembly reaction in a sodium polyphosphate TPP solution and a QCs solution, and the reaction is repeated multiple times; TPP is used as a physical crosslinker to realize the assembly of QCs on the surface of the PDA coating, and the QCs structure is further introduced on the surface of the third layer of PDA coating;

[0013] 6) The PGS copolymer was dissolved in ultrapure water to prepare a 5-10 wt% aqueous solution. The sample prepared in step 5) was immersed in the resulting PGS solution and stirred at 60-80°C for 8-24 hours to complete the ring-opening reaction. A fourth layer of quaternized chitosan QCs grafted with the PGS copolymer was formed on the surface of the third PDA coating layer, ultimately forming a PGS / QCs / PDA / AgNPs-GO / PDA coating material on the substrate surface.

[0014] Furthermore, in step 1), the cleaning process is to place the material in acetone, ethanol, and deionized water in sequence and ultrasonically clean it for 10-20 minutes; the surface oxidation process is determined according to the specific material type, such as glass is treated with piranha lotion, silicon wafers are treated with ozone, and metal substrates are subjected to low-temperature plasma surface treatment;

[0015] Furthermore, in steps 2) to 6), each time a coating layer is prepared, the sample needs to be washed 3-5 times with deionized water and dried with nitrogen until no water film exists on the surface of the sample;

[0016] Furthermore, in step 2) and step 4), the DA concentration in the Tris-HCl solution of DA is 2-8 mg / ml, and the self-polymerization reaction time is 4-16 h;

[0017] Furthermore, in step 3), the concentration of the GO aqueous dispersion is 5-20 mg / ml, the concentration of the AgNO3 solution is 0.05-0.25 mol / L; the volume ratio of the GO aqueous dispersion to the AgNO3 solution is 5:1-10:1; the ultrasonic power is 80-120 W, the ultrasonic time is 15-30 min, the Vortex time is 2-5 min, the ultra-high speed stirring rate is 1000-1500 rpm / min, and the time is 30-60 min; and the immersion time is 2-4 h;

[0018] Further, in step 5), the concentration of the TPP solution is 0.5-2 mg / ml, and the reaction time is 1-2 h; the degree of quaternization of the QCs is 20-40%, the solution concentration is 0.1-1 wt%, and the reaction time is 2-4 h; and the multiple repetitions are repeated 5-10 times;

[0019] Furthermore, the preparation method of the PGS copolymer in step 6) is as follows: dissolving sulfobetaine methacrylate (SBMA) in deionized water to obtain an SBMA aqueous solution; dissolving a certain amount of GMA in methanol to obtain a GMA methanol solution, and mixing it with the above-mentioned SBMA aqueous solution; placing the reaction system in a constant temperature water bath at 40-60°C, stirring for 5-10 minutes to preheat the solution, then adding ammonium persulfate (APS), stirring again for 5-10 minutes, and then adding sodium bisulfite (SBS). After polymerization for 3-5 hours, it is naturally cooled to room temperature, and deionized water is added to remove unreacted monomers, initiators and other impurities to obtain a white crude product, and then methanol is added to dissolve the crude product. The above impurity removal process is repeated 5-10 times to completely remove impurities therein, and the PGS copolymer is obtained after freeze-drying and grinding.

[0020] Furthermore, the mass fraction of the SBMA aqueous solution is 2-5wt%, the mass fraction of the GMA methanol solution is 5-10wt%, and the volume ratio of the SBMA aqueous solution to the GMA methanol solution is 10:1-5:1; the amount of APS and SBS is 1-2% of SBMA; and the stirring rate is 400-600 rpm / min;

[0021] Furthermore, the prepared PGS copolymer has a molecular weight of 6000-18000, and a molar ratio of GMA / SBMA monomer units in the molecular chain is 30:70-60:40.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1) In this invention, DA, silver nitrate, GO, TPP, QCs, GMA, and zwitterions are carefully selected and combined, and the multilayer coating structure is cleverly designed. A five-layer composite PGS / QCs / PDA / AgNPs-GO / PDA coating is successfully prepared using a combination of in-situ self-polymerization, multi-step impregnation, free radical copolymerization, and ring-opening reactions. This coating simultaneously exhibits AgNPs release and sterilization, QCs contact sterilization, PDA and GO photothermal sterilization, and anti-protein adhesion (antifouling) functions.

[0024] 2) The five-layer structure of the PGS / QCs / PDA / AgNPs-GO / PDA coating material constructed by the present invention complements each other as a whole and has a synergistic effect on the performance of the final material: the first layer of PDA coating is a universal primer, which achieves adhesion between the surface and interface of various materials, ensures that the subsequent coating structure can be formed on various materials, and also provides assistance for the formation of the second layer of AgNPs-GO: PDA can reduce Ag +AgNPs can be formed, and AgNPs-GO can also be fixed on the PDA surface; AgNPs in AgNPs-GO have very excellent antibacterial properties, and GO can make AgNPs evenly dispersed on the coating surface and not easy to aggregate; since AgNPs are not suitable for direct contact with tissues, QCs with excellent biocompatibility are introduced as the fourth layer of coating structure; and the introduction of QCs requires suitable reactive groups, so a third layer of PDA is deposited on the AgNPs-GO surface, which can undergo ionic crosslinking with the amino groups on the PDA and QCs molecular chains through the phosphate groups on TPP; the last layer of PGS structure is copolymerized with SBMA and GMA, and the epoxy groups on GMA can undergo a ring-opening reaction with the amine groups on QCs to achieve crosslinking.

[0025] 3) The various layers of the coating constructed by the present invention can also play a synergistic role in the body, and can play a good bactericidal and anti-adhesion role under the premise of ideal biocompatibility: AgNPs have excellent bactericidal activity, but conventional silver-loaded coatings have serious cytotoxicity problems caused by the initial explosive release of drugs. Therefore, the QCs coating is introduced on the basis of the PDA coating. While greatly increasing the biocompatibility, it forms a physical barrier to the AgNPs below, greatly slowing down their release rate. The quaternary ammonium groups on its surface can play a contact bactericidal role, forming a synergistic effect with the slow-released AgNPs, greatly enhancing the bactericidal efficiency. The PGS coating coated on the QCs coating can play an excellent anti-bacterial adhesion role, fundamentally inhibiting the formation of bacterial biofilms.

[0026] 4) The present invention innovatively uses a PGS coating based on a QCs coating, wherein PGS is a copolymer of GMA and SBMA. The epoxy groups it carries can react with the QCs amino group (-NH2) through a ring-opening reaction to achieve the introduction of PGS on the coating. The reaction conditions are easy to achieve, and various chemical cross-linking agents are not involved in the reaction process, which can maximize its biocompatibility.

[0027] 5) The PGS / QCs / PDA / AgNPs-GO / PDA coating constructed in the present invention can be combined with various substrates and has good universality. It can be used for antibacterial purposes in various scenarios, such as the surfaces of orthopedic, dental, and plastic surgery implants, and can effectively prevent the occurrence of implant-related infections. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the preparation process of coating materials with synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions;

[0029] Figure 2 is the NMR result of PGS copolymer;

[0030] Figure 3 The surface SEM image of the coating material with synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions;

[0031] Figure 4 The surface contact angle results of the coating material with synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Comparative Example 1

[0034] 1) Ultrasonic cleaning of glass (1 x 1 x 0.2 cm cubes, sheets, for in vitro experiments; 1 cm long, 1 mm diameter cylindrical samples for in vivo experiments) was performed using acetone, ethanol, and deionized water, followed by surface oxidation using piranha wash.

[0035] 2) Prepare a Tris-HCl solution (pH = 8.5) containing 4 mg / ml DA. Immerse the surface-oxidized glass slide in the DA solution and react at room temperature for 8 hours to form a first layer of PDA coating on the substrate surface.

[0036] 3) Prepare a 10 mg / ml GO aqueous solution, then perform ultrasonic dispersion for 15 min, vortex oscillation for 5 min, and stirring at 2000 rpm / min for 60 min. Then, add an equal volume of 0.1 mol / L silver nitrate solution dropwise under light-proof and ultrasonic conditions, and stir at 2000 rpm / min for 60 min to obtain Ag. + -GO dispersion. The sample prepared in step 2) was immersed in the above Ag + -GO dispersion for 4 h, a second layer of AgNPs-GO coating structure was formed on the surface of the PDA coating;

[0037] 4) The sample prepared in step 3) was added to a Tris-HCl solution (pH=8.5) containing 4 mg / ml DA to form a third layer of PDA coating structure on the surface of the AgNPs-GO coating.

[0038] 5) The sample in step 4) was immersed in 1 mg / ml TPP and 1 wt% QCs solution successively for 2 h, and QCs were introduced as the fourth layer of the coating structure to prepare a QCs / PDA / AgNPs-GO / PDA coating material.

[0039] The contact angle of the sample obtained in the control example was 56°; the biocompatibility was good, and the CCK-8 test of the sample extract showed that the relative cell activity was 85% after 7 days; the bacterial adhesion test showed that bacterial biofilm was formed, and the inhibition zone test showed that the diameter of the inhibition zone was 2.6 cm; the rat femoral infection model showed that a certain amount of bacteria adhered to the sample surface, and the tissue fluid was diluted 1*10 5 After doubling, 50ul of the sample was plated and the number of colonies was 480±32. The number of colonies was 1205±105 when 50ul of the sample extract (the sample was placed in 1ml PBS and shaken at 37°C for 24h) was plated.

[0040] Example 1

[0041] 1) Ultrasonic cleaning of the glass was performed using acetone, ethanol, and deionized water in sequence, followed by oxidation treatment of the surface using piranha wash;

[0042] 2) Prepare a Tris-HCl solution (pH = 8.5) containing 4 mg / ml DA. Immerse the surface-oxidized glass slide in the DA solution and react at room temperature for 8 hours to form a first layer of PDA coating on the substrate surface.

[0043] 3) Prepare a 10 mg / ml GO aqueous solution, then perform ultrasonic dispersion for 15 min, vortex oscillation for 5 min, and stirring at 2000 rpm / min for 60 min. Then, add an equal volume of 0.2 mol / L silver nitrate solution dropwise under light-proof and ultrasonic conditions, and stir at 2000 rpm / min for 60 min to obtain Ag. + -GO dispersion. The sample prepared in step 2) was immersed in the above Ag + -GO dispersion for 4 h, a second layer of AgNPs-GO coating structure was formed on the surface of the PDA coating;

[0044] 4) The sample prepared in step 3) was added to a Tris-HCl solution (pH=8.5) containing 4 mg / ml DA to form a third layer of PDA coating structure on the surface of the AgNPs-GO coating.

[0045] 5) The sample in step 4) was immersed in 1 mg / ml TPP and 2 wt% QCs solution successively for 2 h each, introducing QCs as the fourth coating layer;

[0046] 6) Prepare 2wt% SBMA aqueous solution and 5wt% GMA methanol solution, mix the above solutions in a ratio of 10:1; place the reaction system in a constant temperature water bath at 60°C, stir at 400rpm / min for 10min to preheat the solution, then add APS, stir again for 5-10min and add SBS. After polymerization for 5 hours, naturally cool to room temperature, add deionized water to remove unreacted monomers, initiators and other impurities to obtain a white crude product, then add methanol to dissolve the crude product. The above impurity removal process is repeated 5 times until the impurities are completely removed. Then freeze-dry and the obtained product is recorded as PGS. Its NMR results are as follows Figure 2 The copolymer was dissolved in ultrapure water to prepare a 5 wt% aqueous solution. The sample prepared in step 5) was immersed in the PGS solution and stirred at 60°C for 24 hours to obtain a PGS / QCs / PDA / AgNPs-GO / PDA coating material.

[0047] The sample surface obtained in this embodiment is as follows Figure 3 As shown, the water contact angle is 16° (as Figure 4 ); good biocompatibility; CCK-8 assay of sample extract showed that the relative cell activity was 90% after 7 days; bacterial adhesion assay showed no bacterial biofilm formation; inhibition zone assay showed that the diameter of the inhibition zone was 2.3 cm; rat femoral infection model showed that no bacteria adhered to the sample surface; tissue fluid dilution 1*10 5 After doubling, 50ul of the sample extract was plated, showing the number of colonies was 33±4, and 50ul of the sample extract was plated, showing the number of colonies was 66±15.

[0048] Example 2

[0049] 1) Ultrasonic cleaning of the glass was performed using acetone, ethanol, and deionized water in sequence, followed by oxidation treatment of the surface using piranha wash;

[0050] 2) Prepare a Tris-HCl solution (pH = 8.5) containing 4 mg / ml DA. Immerse the surface-oxidized glass slide in the DA solution and react at room temperature for 8 hours to form a first layer of PDA coating on the substrate surface.

[0051] 3) Prepare a 10 mg / ml GO aqueous solution, then perform ultrasonic dispersion for 15 min, vortex oscillation for 5 min, and stirring at 2000 rpm / min for 60 min. Then, add an equal volume of 0.1 mol / L silver nitrate solution dropwise under light-proof and ultrasonic conditions, and stir at 2000 rpm / min for 60 min to obtain Ag. + -GO dispersion. The sample prepared in step 2) was immersed in the above Ag + -GO dispersion for 4 h, a second layer of AgNPs-GO coating structure was formed on the surface of the PDA coating;

[0052] 4) The sample prepared in step 3) was added to a Tris-HCl solution (pH=8.5) containing 4 mg / ml DA to form a third layer of PDA coating structure on the surface of the AgNPs-GO coating.

[0053] 5) The sample in step 4) was immersed in 1 mg / ml TPP and 1 wt% QCs solution successively for 2 h each, introducing QCs as the fourth coating layer;

[0054] 6) Prepare a 2 wt% aqueous solution of SBMA and a 5 wt% methanolic solution of GMA, and mix them in a ratio of 10:1. Place the reaction system in a constant temperature water bath at 60°C and stir at 400 rpm / min for 10 minutes to preheat the solution. Then, add APS, stir again for 5-10 minutes, and then add SBS. After polymerization for 5 hours, naturally cool to room temperature. Add deionized water to remove unreacted monomers, initiators, and other impurities to obtain a white crude product. Methanol is then added to dissolve the crude product. This impurity removal process is repeated 5 times until all impurities are completely removed. The product is then freeze-dried and designated PGS. Dissolve the copolymer in ultrapure water to prepare a 10 wt% aqueous solution. Immerse the sample prepared in step 5) in the PGS solution and react at 60°C with stirring for 72 hours to obtain the PGS / QCs / PDA / AgNPs-GO / PDA coating material.

[0055] Compared with Example 1, the concentration of the PGS solution was increased, and the water contact angle of the sample obtained in this example was 11°; the biocompatibility was good, and the CCK-8 test of the sample extract showed that the relative cell activity was 92% after 7 days; the bacterial adhesion test showed no bacterial biofilm formation, and the inhibition zone test showed that the diameter of the inhibition zone was 2.1 cm; the rat femoral infection model showed that no bacteria adhered to the sample surface, and the tissue fluid was diluted 1*10 5 After doubling, 50ul of the sample extract was plated, showing a colony count of 62±5, and 50ul of the sample extract was plated, showing a colony count of 12±3.

[0056] Example 3

[0057] 1) Ultrasonic cleaning of the glass was performed using acetone, ethanol, and deionized water in sequence, followed by oxidation treatment of the surface using piranha wash;

[0058] 2) Prepare a Tris-HCl solution (pH = 8.5) containing 4 mg / ml DA. Immerse the surface-oxidized glass slide in the DA solution and react at room temperature for 8 hours to form a first layer of PDA coating on the substrate surface.

[0059] 3) Prepare a 10 mg / ml GO aqueous solution, then perform ultrasonic dispersion for 15 min, vortex oscillation for 5 min, and stirring at 2000 rpm / min for 60 min. Then, add an equal volume of 0.2 mol / L silver nitrate solution dropwise under light-proof and ultrasonic conditions, and stir at 2000 rpm / min for 60 min to obtain Ag. + -GO dispersion. The sample prepared in step 2) was immersed in the above Ag + -GO dispersion for 4 h, a second layer of AgNPs-GO coating structure was formed on the surface of the PDA coating;

[0060] 4) The sample prepared in step 3) was added to a Tris-HCl solution (pH=8.5) containing 4 mg / ml DA to form a third layer of PDA coating structure on the surface of the AgNPs-GO coating.

[0061] 5) The sample in step 4) was immersed in 1 mg / ml TPP and 1 wt% QCs solution successively for 2 h each, introducing QCs as the fourth coating layer;

[0062] 6) Prepare a 2 wt% aqueous solution of SBMA and a 5 wt% methanolic solution of GMA, and mix them in a ratio of 10:1. Place the reaction system in a constant temperature water bath at 60°C and stir at 400 rpm / min for 10 minutes to preheat the solution. Then, add APS, stir again for 5-10 minutes, and then add SBS. After polymerization for 5 hours, naturally cool to room temperature. Add deionized water to remove unreacted monomers, initiators, and other impurities to obtain a white crude product. Methanol is then added to dissolve the crude product. This impurity removal process is repeated 5 times until all impurities are completely removed. The product is then freeze-dried and designated PGS. Dissolve the copolymer in ultrapure water to prepare a 5 wt% aqueous solution. Immerse the sample prepared in step 5) in the PGS solution and react at 60°C with stirring for 24 hours to obtain the PGS / QCs / PDA / AgNPs-GO / PDA coating material.

[0063] Compared with Example 1, the concentration of the AgNO3 solution was increased, and the loading amount of AgNPs was increased. The water contact angle of the sample obtained in this example was 17°. The CCK-8 test of the sample extract showed that the relative cell activity was 82% after 7 days. No bacterial biofilm was formed in the bacterial adhesion test, and the inhibition zone test showed that the diameter of the inhibition zone was 3.9 cm. The rat femoral infection model showed that no bacteria adhered to the sample surface, and the tissue fluid was diluted 1*10 5 After doubling, 50ul of the sample extract was plated and the number of colonies was 18±2. The number of colonies was 22±4 when 50ul of the sample extract was plated.

[0064] The foregoing description is merely a partial list of preferred embodiments of the present invention, intended only to facilitate understanding of the present invention and not to limit the present invention. It should be noted that variations and improvements are possible without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A coating material based on AgNPs, QCs and zwitterions with synergistic antibacterial and antifouling functions, characterized by: A multi-step impregnation method was used to sequentially form a first layer of polydopamine (PDA) coating, a second layer of nanosilver-graphene oxide (AgNPs-GO) coating, a third layer of PDA coating, and a fourth layer of quaternized chitosan (QCs) coating with a PGS copolymer grafted on the surface on the substrate to obtain a PGS / QCs / PDA / AgNPs-GO / PDA coating material; the PGS copolymer was prepared by copolymerization of zwitterionic sulfobetaine methacrylate (SBMA) and glycidyl acrylate (GMA).

2. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs, and zwitterions according to claim 1, wherein: The steps include: 1) After cleaning the base material, perform surface oxidation treatment on it according to the material characteristics; 2) Prepare a Tris-HCl solution of DA at a pH of 8.5, immerse the substrate in the Tris-HCl solution of DA, and form a first layer of PDA coating on the substrate surface through the self-polymerization reaction of DA; 3) Prepare GO aqueous dispersion under ultrasound, Vortex oscillation and ultra-high speed stirring conditions, then slowly add silver nitrate solution under light-proof and ultrasound conditions, and obtain Ag after ultra-high speed stirring. + -GO dispersion; the sample prepared in step 2) is immersed in the above Ag + -GO dispersion, PDA was used to achieve Ag under oscillation conditions. + After sufficient reduction, a second layer of AgNPs-GO coating is formed on the surface of the first layer of PDA coating; 4) adding the sample prepared in step 3) to the Tris-HCl solution of DA prepared in step 2) for in-situ self-polymerization to form a third PDA coating on the surface of the second AgNPs-GO coating; 5) The sample in step 4) is subjected to self-assembly reaction in a sodium polyphosphate TPP solution and a QCs solution, respectively. TPP acts as a physical crosslinker to enable the assembly of QCs on the surface of the PDA coating, thereby introducing QCs on the surface of the third layer of PDA coating; 6) The PGS copolymer is dissolved in ultrapure water to prepare a 5-10 wt% aqueous solution, and the sample prepared in step 5) is immersed in the obtained PGS solution. The mixture is stirred at 60-80°C for 8-24 hours to complete the ring-opening reaction, thereby obtaining a fourth layer of QCs coating with the PGS copolymer grafted on the surface; finally, a PGS / QCs / PDA / AgNPs-GO / PDA coating material is prepared on the surface of the substrate material.

3. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions according to claim 2, characterized in that: In step 1), the cleaning process is to place the material in acetone, ethanol, and deionized water in sequence and ultrasonically clean it for 10-20 minutes. The surface oxidation process is determined by the specific material type. Glass is treated with piranha lotion, silicon wafers are treated with ozone, and metal substrates are treated with low-temperature plasma surface treatment.

4. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions according to claim 2, characterized in that: In steps 2) to 6), each time a coating layer is prepared, the sample needs to be washed with deionized water 3-5 times and dried with nitrogen until no water film exists on the surface of the sample.

5. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions according to claim 2, characterized in that: In step 2) and step 4), the DA concentration in the Tris-HCl solution of DA is 2-8 mg / ml, and the self-polymerization reaction time is 4-16 hours.

6. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs, and zwitterions according to claim 2, characterized in that: In step 3), the GO concentration in the GO aqueous dispersion is 5-20 mg / ml, the AgNO3 solution concentration is 0.05-0.25 mol / L; the volume ratio of the GO aqueous dispersion to the AgNO3 solution is 5:1-10:1; the ultrasonic power is 80-120 W, the ultrasonic time is 15-30 minutes, the Vortex oscillation time is 2-5 minutes, the ultra-high-speed stirring rate is 1000-1500 rpm / min, and the time is 30-60 minutes; and the immersion time is 2-4 hours.

7. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions according to claim 2, characterized in that: In step 5), the concentration of the TPP solution is 0.5-2 mg / ml, and the reaction time is 1-2 hours. The degree of quaternization of the QCs is 20-40%, the solution concentration is 0.1-1 wt%, and the reaction time is 2-4 hours. The sample is immersed in the TPP solution and then the QCs solution for reaction, and this process is repeated 5-10 times.

8. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions according to claim 2, characterized in that: The preparation method of the PGS copolymer in step 6) is as follows: dissolving SBMA in deionized water to obtain an SBMA aqueous solution; taking a certain amount of GMA and dissolving it in methanol to obtain a GMA methanol solution, and mixing it with the above-mentioned SBMA aqueous solution; placing the reaction system in a constant temperature water bath at 40-60°C, stirring for 5-10 minutes to preheat the solution, then adding ammonium persulfate (APS), stirring again for 5-10 minutes, and then adding sodium bisulfite (SBS). After polymerization for 3-5 hours, it is naturally cooled to room temperature, deionized water is added to remove impurities to obtain a white crude product, and methanol is then added to dissolve the crude product. The above impurity removal-dissolution process is repeated 5-10 times, and the PGS copolymer is obtained after freeze-drying and grinding.

9. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions according to claim 8, characterized in that: The mass fraction of the SBMA aqueous solution is 2-5wt%, the mass fraction of the GMA methanol solution is 5-10wt%, and the volume ratio of the SBMA aqueous solution to the GMA methanol solution is 10:1-5:1; the mass of APS and SBS is 1-2% of SBMA; and the stirring rate is 400-600 rpm / min.

10. The method for preparing a coating material having synergistic antibacterial and antifouling functions based on AgNPs, QCs and zwitterions according to claim 8, characterized in that: The molecular weight of the PGS copolymer is 6000-18000, and the molar ratio of the monomer units GMA / SBMA in the molecular chain is 30:70-60:40.

Images