Preparation And Antibacterial Properties Of Metal-organic Frameworks Based Polylactic Acid Composite Fibrous Membranes

The reproduction and spreading of bacteria have become great threatens to human’s life and health.It is urgent to develop novel antibacterial materials.Metal-organic frameworks based polylactic acid（PLA）composite fibrous membranes possess highly cross-linked hierarchical porous structure and easily functionalized surface,which exhibit great application prospects as antibacterial membranes and dressings.However,the structural design and application investigations of MOFs based PLA composite fibrous membranes are still incomplete,such as the interaction between MOFs based PLA composite fibrous membranes and bacteria is not clear.The antimicrobial active components cannot be released on demand and the weak response to endogenous/exogenous stimuli.In this research,a serious of MOFs based PLA composite fibrous membranes based on electrospinning and molecular assembling technologies were constructed to investigate the structural and antibacterial properties as well as elucidate the antibacterial mechanism.The main contents of the research are listed as following:（1）Preparation and antibacterial properties of sustained releasing MOFs PLA composite fibrous membranes.To investigate the antibacterial properties and interaction mechanisms of MOFs PLA fibrous membrane,Ag₂[HBTC][im]-PLA and Ag₂[HBTC]-PLA were synthesized.Antibacterial efficiencies of Ag₂[HBTC][im]-PLA against Escherichia coli,Pseudomonas aeruginosa,Staphylococcus aureus and Mycobacterium smegmatis were more than 95%,respectively.Wound healing rate of bacterial infected rice wound was more than 99.9%after treatment with Ag₂[HBTC][im]-PLA.Ag₂[HBTC]-PLA exhibited highly antibacterial properties against E.coli and S.aureus.Proteomics analysis indicated that the destroying of energy metabolism,dissipation of proton motive,decreasing the capacity of transport system may be associated with antibacterial action of the composites.（2）Preparation and photothermal/photodynamic combined antibacterial performance of near-infrared light（NIR）triggered MOFs based PLA composite fibrous membranes.To overcome the limitations of single antibacterial mode and the insensitive to exogenous stimuli of MOFs based PLA fibrous membranes,MXene/ZIF-8/PLA was designed and synthesized based on the near infrared light responsiveness of MXene and the interface interaction between MXene and ZIF-8.It exhibited high photothermal conversion efficiency and properties to sensitize the singlet oxygen generation.MXene/ZIF-8/PLA showed in vitro bacterial killing effects of more than 99%under NIR irradiation for 5 min,thus promoting the regeneration of bacteria-infected wound tissue effectively.（3）Preparation and antibacterial properties of NIR/p H dual stimuli-responsive MOFs based PLA composite fibrous membranes（CIZPP）.CIZPP with NIR/p H dual stimuli-responsive ability were synthesized to achieve targets identification of bacterial infected sites and stimuli-responsive delivery of the antimicrobial components based on PTT/PDT properties.Studies indicated CIZPP could realize the responsive delivery of antibacterial components under the stimulation of NIR and the microenvironment of bacterial infection as well as NIR triggered“on-off”antibacterial properties.CIZPP exhibited antibacterial properties of more than 99%,significantly higher than that of the control groups with single component.（4）Preparation and antibacterial properties of NIR/bacterial infected microenvironment/electricity stimuli-responsive MOFs based PLA composite fibrous membranes.To improve the chemo-therapy and multiple stimuli-responsive antibacterial abilities from the atomic structure level,single atom Zn doping hollow carbon capsules EC was investigated taking bacteria as templates.The biological templates could anchor MOFs through electrostatic interaction to prevent agglomeration thus obtaining atomically dispersed Zn active site doped carbon materials after carbonization.Based on the results,photothermal/photodynamic/chemo-dynamic therapy and joule heating multifunctional antibacterial membrane Ag NWs/EC-PCL-PLA（PPAE）was constructed,that can significantly eliminate bacterial colonization at the wound site,promote epidermal growth and collagen deposition,thereby accelerating wound healing,showing good application prospects as biomedical materials.