Preparation And Properties Of Betaine Ester Quaternary Ammonium Salt Antibacterial Hydrogel Material That Is Hydrolyzable In Weak Alkaline Aqueous Solution

Microbial infections have always been a major problem for humans.In order to fight against microbials,antibiotic drugs were used.A number of small molecule antimicrobial drugs were subsequently developed,but both antibiotics and small molecule antimicrobials are defective.In recent years,with the abuse of antibiotics,the resistance of microorganisms to antibiotics has become stronger and stronger,while small molecule antimicrobial agents can not be widely used because of their volatile,residual and toxic defects.Therefore,the development of universal,non-toxic and antibacterial polymer materials with excellent antibacterial properties is imminent.In this paper,a betaine ester quaternary ammonium salt antibacterial hydrogel was prepared based on thiol-ene click reaction.First,POSS was used as the core,DPT was used as the arm.A POSS molecule having eight dimethylamino groups was prepared by a thiol-ene click reaction.Then,a betaine ester quaternary ammonium salt antibacterial hydrogel was formed by crosslinking with hexanediol chloroacetate and cetyl chloroacetate via highly efficient quaternization reaction.The gel was characterized by Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance(NMR)and X-ray photoelectron spectroscopy(XPS).The surface wettability of the antibacterial hydrogel was investigated by the automatic optical contact angle tester.The results showed that the hydrophobic groups of ester and long alkyl groups of the betaine ester quaternary ammonium salt gel were concentrated on the surface of the hydrogel,while the hydrophilic groups were covered inside the gel.The mechanical properties of the antibacterial hydrogel were studied by means of double column tension machine.It was found that the compressive stress and elastic modulus of the antibacterial hydrogel increased continuously with the increase of hexanediol chloroacetate,the maximum compressive stress was 0.356 MPa,and the maximum elastic modulus was 4.38 MPa.Fluorescence microscopy was used toobserve stained live and dead bacteria to characterize the antibacterial activity of the hydrogel.The results showed that betaine ester quaternary ammonium salt gel had excellent killing effect on Escherichia coli(E.coli)and Staphylococcus aureus(S.aurues).Moreover,the more cetyl chloroacetate used,the better the antibacterial effect is.The highest bactericidal rates of E.coli and S.aureus are 93% and 95%.The swelling rate and hydrolytic properties of the antibacterial hydrogel were studied by changing the mass of the gel in the PBS buffer.The results showed that the maximum swelling rate of the hydrogel was 791%,and the gel could be hydrolyzed under weak alkaline aqueous solution(PH=8.0),and achieved a complete hydrolysis for less than6 h.In the next study,based on the prepared betaine quaternary ammonium salt antibacterial gel,the photothermal conversion agent graphene oxide(GO)was incorporated to prepare a quaternary ammonium salt and photothermal synergistic antibacterial compound.It can kill microorganisms quickly and maintain a killing effect for a long time.The absorption intensity of hydrogel at 808 nm near-infrared was investigated by UV-Vis-NIR spectrophotometer.The photothermal effect at near-infrared at 808 nm was studied by thermal infrared imager.The glue can be heated up to 80 °C in the near-infrared light for up to 120 s.The bactericidal properties of hydrogels were explored by bacterial growth curves and live bacteria staining antibacterial tests.The results showed that under the near-infrared(NIR)laser irradiation,the growth of E.coli and S.aurues was well inhibited,and against Escherichia coli E.coli and Staphylococcus aureus S.aurues has a maximum sterilization rate of 99.9%.GO/Quaternary Ammonium Salt Antibacterial Hydrogel has excellent photothermal conversion ability and bactericidal ability,and has great potential in the medical antibacterial field.