The Preparation And Biological Properties Of Antimicrobial Nanofibers Based On Aggregation-induced Emission Molecules

Bacterial infection has always been one of the important threats to public health security.Acute or chronic diseases caused by pathogenic bacteria not only endanger human health,but also cause huge economic losses worldwide every year.The overuse of antibiotics leads to the emergence of drug-resistant bacteria,which brings a new problem to the treatment of bacterial infection.It is urgent to develop an effective,stable and safe antimicrobial strategy.In view of the urgent need for excellent antibacterial materials in clinical,AIE nanofibers with amphiphilic molecule as the shell was designed and prepared in this paper.Meanwhile,a series of peptides with different amino acid sequences were used to functionalized the AIE nanofibers,and peptide-AIE nanofibers was constructed.In this paper,the in vitro and in vivo biological properties of the constructed peptide-AIE nanofibers were studied,and the influence of peptide sequence on the biological properties of nanofibers was revealed as follows.First of all,AIEgens 2-{3-[5-（4-Diphenylamino-phenyl）-thiophen-2-yl]-1-phenyl-allylid--ene}-malononitrile was modified by DSPE-PEG₂₀₀₀ and DSPE-PEG₂₀₀₀-Mal molodules to construct AIE nanofibers in this paper,and maleic anhydride group（-Mal）was introduced into the nanofibers.The antimicrobial peptide（HHC36,KRWWKWWRR）,polylysine（CKn）,polyarginine（CRn）and polytryptophan（CWn）were grafted onto the fiber surface by addition reaction of mercapto group（-SH）with maleic anhydride group.The physicochemical properties such as reactive oxygen generation efficiency and photostability of the nanofibers were studied.Secondly,this paper studied the biological properties of peptide-AIE nanofibers in vitro,and revealed the influence of peptide sequence on the biological properties of nanofibers.The results showed that nanofibers modified with long-chain polylysine（CK18）could more effectively collect and mark bacteria,and could effectively kill bacteria through photodynamic therapy.The antibacterial rate of NFs-CK18 against S.aureus,E.coli and other pathogenic bacteria reached more than 95%.The results of antibacterial mechanism showed that the nanofibers could kill bacteria by destroying the membrane structure of bacteria.At the same time,the constructed peptide-AIE nanofibers have excellent tracer and killing effects on a variety of cancer cells.Fluorescence co-localization technology revealed that peptide-AIE nanofibers quickly assemble at the lipid droplet position after entering cancer cells and destroy the cancer cell structures through photodynamic therapy.Finally,a skin wound infection model was established in C57 mice to study the biological properties of peptide-AIE nanofibers in vivo.The results showed that nanofibers screened by in vitro experiments can effectively resist the wound bacterial infection,kill more than 95%of the infected bacteria,reduce the production of inflammatory cells around the wound,and effectively promote the skin healing at the wound.In summary,AIE nanofibers were modified by a series of peptides with different amino acid sequences to construct a peptide-AIE nanofibers,which realized the functions of bacterial aggregation,tracer and inhibition,and provided a new strategy to deal with the clinical challenge of bacterial infection.