A Research Of Construction Of Antibacterial Hydrogel Based On Probiotic Extracts And S-nitrosothiols

As a natural physical barrier between the body and the outside,once skin is damaged to form a wound,the internal soft tissue will face the threat of pathogens during the long reconstruction process.Traditional antibiotic therapy has been the mainstream clinical method for preventing infection for several decades.However,the overuse of antibiotics has led to the rapid evolution of drug-resistant bacteria.In addition,with a rage of COVID-19,the increasing use of antibiotic drugs has accelerated the development and spread of drug-resistant bacteria.Meanwhile,developing of new antibiotics entails huge costs,and long development cycles make it difficult to compete with resistance that can change in weeks.Therefore,develop non-antibiotic antimicrobial materials and therapeutic strategies are urgently needed to promote healing of infectious wounds and avoid drug resistance.In recent years,the immune mechanism of the immune cells,which secrete or produce various kinds of gas molecules with bactericidal effect,provides people with valuable inspiration.This is where gas therapy comes in.For example,inspired by macrophage-secreted nitric oxide(NO)molecules that have a variety of biological functional properties,NO-led strategies have been widely explored and applied in the design and research of bionic antibacterial therapy.However,the therapeutic and biosafety of NO is highly dependent on its concentration and location in the body.Moreover,the short half-life and limited diffusion radius of NO itself limit clinical application seriously.Therefore,to disinfect pathogens thoroughly and improve the treatment effect,NO gas often needs to be combined with other strategies.Apart from that,probiotics living symbiotically with humans show obvious inhibition behavior against pathogenic bacteria in the natural competition process,which provides an important reference for the design of non-antibiotic strategies.Among them,the typical therapeutic strategies are beneficial bacteriological therapy and engineering bacteriological therapy,which involves the introduction of beneficial or attenuated modified colonies to colonize the human body,and then perform a competitive or other biological functions to cure the pathogen infection.However,there is a safety issue that cannot be ignored.Direct introduction of live bacteria into the wound may lead to the risk of bacteremia or septicemia.Therefore,how to effectively apply the bacteriostatic effect of probiotics to wound treatment without causing additional risks still needs further exploration.To sum up,it is of great research significance to realize the combination of low-risk probiotics and low-dosage NO for efficient synergistic antibacterial treatment of infected wounds.Therefore,in this paper,PES was obtained by a simple and feasible hydrothermal method,and combined with the NO donor molecule,S-nitrosothiols(RSNO),through hydrogen-bonded to construct a biomimetic microparticle with a structure similar to the tailspike of a phage.This biomimetic microparticle was labeled PES-RSNO.The PES-RSNO were encapsulated in a polyvinyl alcohol(PVA)-polyacrylic acid(PAA)hydrogel that doped with graphene oxide(GO).Thus,a dual-mode antibacterial hydrogel(DMAH)was designed with both dark long-term sterilization and light short-term rapid bactericidal properties.This paper is mainly divided into the following three sections:1.Construction of biomimetic microparticles PES-RSNO based on probiotic extracts and S-nitrosothiols.PES-RSNO particles were successfully obtained by physical mixing between PES prepared by hydrothermal method and RSNO prepared by ice-bath reaction.The morphology and structure of PES-RSNO were characterized by SEM,Zeta potential and DLS.The hydrogen bonding between PES and RSNO and phage-like structure were verified by Dindahl effect test and protein molecular dynamics simulation.At the same time,the bactericidal mechanism of PES-RSNO was explored by means of plate coating,bacteriomics and intracellular reactive oxygen species test.The results showed that the excellent antibacterial ability of PES-RSNO was due to the synergistic effect between the thermostable bacteriocin with a phage-like tail nail protein structure of PES-RSNO and the continuous release of NO.2.Construction and in vitro antibacterial study of antibacterial hydrogel based on probiotic extracts and S-nitrosothiols.PES-RSNO was encapsulated in GO doped PVA-PAA hydrogel to prepare DMAH hydrogel,and the synthesis of DMAH was further verified by SEM,UV-vis,Raman,XRD and other characterization methods.The photothermal performance test,tensile compression test and swelling test show that DMAH was a kind of hydrogel with good photothermal performance,excellent mechanical properties,high load capacity and stable structure.Meanwhile,in vitro long-term dark antibacterial experiment and photothermal /NO short-term antibacterial experiment showed that DMAH had excellent dual-mode antibacterial function of dark long-term antibacterial and light short-term rapid bactericidal properties.In addition,cell scratch experiments showed that DMAH could effectively promote cell migration.Therefore,it is expected that DMAH to be used in the treatment of infected wounds and promote the repair of infected wounds.3.Study on in vivo antibacterial and promote wound healing of antibacterial hydrogel based on probiotic extracts and S-nitrosothiols.Finally,the antibacterial effects in vivo of DMAH-guided dark long-term antibacterial mode and light short-term antibacterial mode were tested by building a rat MRSA infectious wound model.The results revealed that the antibacterial rate in vivo of the two modes reached99.84% and 97.13% respectively,indicating that DMAH realized effective treatment of the two antibacterial modes in vivo under different conditions.Furthermore,Giemsa staining,H&E staining,Masson staining,immunohistochemical(IHC)staining and other tests were tested to show that the biosafe DMAH could effectively eliminate pathogens,reduced inflammation,promoted collagen deposition and angiogenesis by dual-mode antibacterial strategy,which had far-reaching significance for non-antibiotic treatment strategies in wound repair.