Studies On The Construction Of Quaternary Ammonium Salt Copolymer Aggregates And Its Biofilm Eradication Mechanism

This paper focuses on the synthesis of quaternary ammonium-based copolymers,the construction of micelles and the ability to remove and inhibit biofilms.Methacrylic acid N,n-dimethylaminoethyl ester（DMAEMA）was quaternized with long-chain bromoalkanes,and then copolymerized with polyethylene glycol methacrylate（PEGMA）to obtain a copolymer.The copolymer self-assembled to form an antibacterial micelle,the properties and the capability of anti-biofilm were investigated.The main work of this paper is as follows:1.Preparationofcopolymers(PQACs₁₀-b/co-PEGMA₁₀,PQACf₁₀-co-PEGMA₁₀):quaternary ammonium antibacterial monomers（QACs,QACf）were synthesized by quaternary ammonium synthesis from DMAEMA and bromoalkanes;.The copolymers were characterized by IR,X-ray photoelectron spectroscopy and Proton NMR.2.Self-assembly of Copolymer Micelles:the self-assembly of copolymers was made by dropping bad solvents and direct dissolution,and the properties of micelles were investigated.The morphology of the copolymer micelles was observed by Scanning electron microscope and transmission electron microscope,and the size and zeta potential of the micelles were p H-responsive,and the size of PQACs₁₀-co-PEGMA₁₀micelles could be controlled by the amount of water added.3.Ability of copolymer micelles to scavenge biofilms:the antimicrobial sensitivity and minimum biofilm clearance concentration（MBEC）of antibacterial micelles were measured using Staphylococcus aureus.The results of MIC and MBEC indicated that the PQACs₁₀-b-PEGMA₁₀micelles had poor antimicrobial sensitivity and ability to clear biofilms,which might be due to the formation of a shell with PQACs as the core.The minimum inhibitory concentration of PQACs₁₀-b-PEGMA₁₀micelles were composed of PQACs₁₀-b-PEGMA₁₀micelles,it is stable at different p H,and can not effectively expose quaternary ammonium groups in the biofilm.The MIC and Mbec of PQACs₁₀-co-PEGMA₁₀micelles were 64μg/m L and 128μg/m L,respectively,with good antimicrobial sensitivity and biofilm clearance.The Mic of PQACf₁₀-co-PEGMA₁₀micelles and the MBEC of 95%biofilm scavenge were 32μg/m L and 16μg/m L,respectively,which indicated that fluoropolymer micelles further enhanced the ability of biofilm scavenge.Four.Copolymer Micelle coating inhibits biofilm ability:antibacterial micelle coating was constructed on the surface of silicon wafer by dropping micelle aqueous solution.The anti-adhesion and bactericidal properties of PQACs₁₀-co-PEGMA₁₀coating were nearly 100%and 99.99%,respectively.The anti-adhesion and bactericidal properties of PQACf₁₀-co-PEGMA₁₀coating were nearly 100%The results show that the random copolymer has better biofilm clearance efficiency than the block copolymer,and the synthesis method of the random copolymer is simple,ph-responsive micelles can improve the permeability and enrichment,and the removal efficiency of biofilm is also enhanced,which makes the coating have potential value in the fields of medical devices and daily necessities.The introduction of fluorocarbon chains further enhanced the antimicrobial sensitivity of the micelles and the ability to prevent and remove biofilms,and enhanced the long-term antibacterial properties of the coatings,increasing the application potential of the coatings in the field of long-term antibacterial.