Design And Synthesis Of In Situ Renewable N-halamine Hydrogels And Study On Their Specificity For Antibacterial Performances

Pathogenic bacteria infection has always been one of the most common diseases in clinical practice,impacting the quality of human life,and even threatening human life and health.Due to its excellent biocompatibility,softness,super permeability and on-demand plasticity,antibacterial hydrogels can be widely used in many biomedical materials such as wound dressings,contact lenses and implant materials.With the rapid development of modern medicine and materials science,more attention has been paid to the development of new broad-spectrum antibacterial hydrogels to deal with the problem of pathogen infection in various conditions.Therefore,it is significant to develop antibacterial hydrogels which can regenerate in situ and have high selective antibacterial activity against pathogenic bacteria.Based on these mentioned above,this paper performed the following research:First,a N-halamine polymer pMAG-Cl was synthesized via the combination of amination reaction,free radical polymerization and chlorination treatement.A quaternary ammonium salt[VBIM]Br was synthesized by the reaction of 1-vinylimidazole with n-butyl bromide.And SPP hydrogels and PP hydrogels were successfully synthesized by using pMAG-Cl and[VBIM]Br as effective antibacterial components by a freeze-thaw starategy followed by Ca²⁺ crosslinking.The morphology and structure of the hydrogels were systematically characterized by SEM,FTIR and XPS.Then water content,swelling rate and moisturizing impact of the SPP hydrogel were tested.The mechanical strength of the hydrogels were investigated,and the impacts of SA:PVA feeding ratio,soaking time and the amount of pMAG-Cl on the mechanical properties of the SPP hydrogel were tested by stretching and compression.Subsequently,using the colony counting method and the inhibition zone test,the specificity of SPP hydrogels toward E.coli and their antibacterial performance were confirmed.Next pMAG-Cl was proven as the effective bacteria-killing component in SPP hydrogel.In addition,the excellent biocompatibility of SPP hydrogel was verified by MTT test,living-dead cell staining and LDH assay.Finally,the starch indicating method combined with plate counting method were employed to confirm the transfer of active Cl⁺ in SPP hydrogels in different conditions.Then the impact of SA:PVA feed ratio on the transfer of active Cl⁺ was proved as well.After a systematic comparison,SPP hydrogels were proved to have a capability of active Cl⁺ transfer in selectivity.Through theoretical calculation,the active Cl⁺ transfer were confirmed by hydrolysis of pMAG-Cl,decomposition of HClO and formation of pMAG-Cl.Also SPP hydrogels have been proven to be successful in wound healing and water disinfection.In the end,the in situ regenerability of SPP hydrogels was confirmed as well.