In-Situ Preparation And Characterization Of AIEgens Labeled Microenvironment-Responsive PVA Quaternary Ammonium Salt

In response to the serious threat of bacterial infections,various antibacterial agents including antibiotics have been developed.Many traditional antibacterial agents are prone to drug resistance resulting in low efficiency,so how to effectively treat bacterial infections remains a huge challenge.At the same time,the release of small molecule antibacterial agents(especially antibiotics)into the environment poses a serious threat to human health by transferring antibiotic-induced resistance genes.Like antibiotics,low molecular weight quaternary ammonium compounds(QAC)are prone to drug resistance and are extremely harmful to the environment due to their cumulative effects.On the contrary,the polymer quaternary ammonium salt has the advantages of low volatility,chemical stability and continuous bacteriostasis,and has attracted widespread attention.This paper is based on the quaternization reaction of polyvinyl alcohol derivatives.By in situ labeling of fluorescent molecules(AIEgens)with aggregation-induced luminescence(AIEgens)properties,the temperature,p H dual response type and simultaneous bacterial imaging and killing The in-situ construction of polymer antibacterial materials is divided into two parts:(1)Through the one-pot quaternization reaction between the tertiary amine group on the polyvinyl alcohol derivative and bromomethyltetraphenylethylene(TPE),a polyvinyl alcohol quaternary ammonium salt(PVA)with temperature and p H response was prepared-TPE).In this step,the TPE group with AIE performance and the quaternary ammonium salt fragment with antibacterial performance are simultaneously introduced in one step,thereby realizing the effective integration of the function of "monitoring and killing bacteria".The experimental results show that PVA-TPE can selectively image and kill Gram-positive bacteria at p H 7.4,while under acidic environment(p H 5.5),it shows enhanced broad-spectrum antibacterial to Gram-negative and positive bacteria active.Moreover,PVA-TPE showed low cytotoxicity against L929,Hep G2 and mammalian red blood cells.In addition,in vivo evaluation further confirmed that PVA-TPE has excellent efficacy in killing Gram-positive bacteria and can accelerate the treatment of skin bacterial infections.This research is the first integrated system that can switch p H to monitor and kill bacteria through a simple one-pot quaternization reaction.(2)In view of the clinical needs of anti-infective functional dressings and the excellent bacterial imaging and killing performance of PVA-TPE,PVA-TPE and sodium alginate(SA)were prepared into SA / PVA-TPE antibacterial composite hydrogel by Ca2 + crosslinking.The experimental results show that as the content of PVA-TPE increases,the linear viscoelastic region and fluorescence properties of the composite gel also increase.In vitro antibacterial experiments show that the composite hydrogel has good bactericidal properties against both Gram-positive and negative bacteria.The activity and proliferation experiments of L929 and BMSC cells also prove that the SA / PVA-TPE composite hydrogel has good biocompatibility,and has great application potential in the biomedical field,especially as an anti-infective dressing.