Assistance In Constructing Antifouling/antibacterial Functional Coatings With Tannic Acid And Its Derivatives

Healthcare-associated infections（HAIs）pose a significant risk of infection to patients,and one of the main causes of infection during the use of biomedical materials is bacterial attachment and subsequent biofilm formation.To address this issue,preparing antifouling/antibacterial functional coatings on the surface of biomedical materials is an effective solution to reduce bacterial spread and growth on material surfaces.This study selects tannic acid and its derivatives as surface adhesives to modify the surface of biomedical materials with two different performance materials,thus creating antifouling/antibacterial functional coatings.The applicability of tannic acid and its derivatives in the preparation of antifouling/antibacterial coatings on the surface of biomedical materials is explored.The specific research content includes the following two main parts:Constructing coatings by combining tannic acid derivatives containing thiolactone（TA-Tla）and three different degrees of polymerization of poly（2-methyl-2-oxazoline）terminated with amino groups（PMOXA-NH₂）.The coatings are formed through the reaction between thiolactone and amino groups,resulting in the formation of amide bonds and thiol groups.The thiol groups can undergo oxidation coupling to form disulfide bonds and can also undergo coupling reactions with the dihydroxyphenyl and trihydroxyphenyl groups in tannic acid derivatives,thereby forming TA-Tla/PMOXA（TP）coatings on the substrate surface.These coatings not only exhibit universality on the substrate surface but also enhance the hydrophilicity of the surface.They effectively prevent the adhesion of bacteria and platelets in the vicinity of the substrate surface,thus preventing the formation of bacterial biofilms.The antifouling performance of the coating is related to the polymerization degree of PMOXA and the content of TA-Tla and PMOXA-NH₂.Scanning electron microscopy observations reveal that a uniform and smooth coating is formed on the surface when the ratio of TA-Tla to PMXOA10 is 1:2.5.Bacterial adhesion experiments and experiments on preventing biofilm formation show that the coating not only has the ability to remove biofilms but also reduces the contamination efficiency of Staphylococcus aureus and Escherichia coli by 90%and 76%,respectively.In biocompatibility experiments,the coating demonstrates a certain level of biocompatibility in both in vitro and in vivo conditions.Creating functional coatings（TA/Honey-GOD,TH-GOD,THG）on the surface of biomedical materials by using tannic acid-assisted honey-derived glucose oxidase to achieve sustained sterilization and anti-infection effects.Diluted honey-derived glucose oxidase is combined with tannic acid.The negative potential of tannic acid in solution combines with the positive potential exhibited by substances in honey to prepare the coatings.These coatings,which are universal on the material surface,produce hydrogen peroxide antimicrobial agents by oxidizing glucose with glucose oxidase in honey,effectively killing bacteria and preventing biofilm formation on the surface,thus promoting wound healing.The uniformity of the coating depends on the content of tannic acid and honey solution.Atomic force microscopy observations reveal the lowest surface roughness of the coating when the ratio of tannic acid to honey is 1:1.Physicochemical studies of the coating show that it not only enhances the hydrophilicity and antioxidation of the material surface but also detects the surface glucose oxidase activity and the release of hydrogen peroxide antimicrobial agents.The coating is prepared on Ti substrate surfaces and gauze substrate surfaces,and experiments on antibacterial and anti-biofilm properties demonstrate a 99.7%inhibition rate against Staphylococcus aureus.The coating exhibits good biocompatibility in biocompatibility experiments.Comparing the coatings prepared using Manuka honey（TA/Honey-MGO,TH-MGO,THM）,the coating with the release of hydrogen peroxide antimicrobial agents is more effective in killing bacteria and promoting wound healing in the inhibition zone and wound healing experiments.