The Structure Design Of MOFs Modified On The Surfance Of Nanofibers And Its Combat To Drug-resistant Bacteria Infections

Wounds infected by drug-resistant bacteria have a long healing cycle and are difficult to treat.If the correct methods are not taken in time to control them,systemic infections and even deaths will be caused.At present,the number of antibacterial drugs that can cope with drug-resistant bacteria infection is decreasing every year.The long lead time and the large investment of new drugs development,coupled with the rapid development of drug-resistant bacteria are complex and changeable,making conventional therapies encounter bottlenecks.It is estimated that if this situation is allowed to continue to develop,the number of deaths caused by drug-resistant bacteria in 30 years will reach 10 million per year,and the economic loss will reach100 trillion USD.It can be seen that wound infections caused by drug-resistant bacteria have constituted a serious problem and one of the serious threats facing human health worldwide.In recent years,the use of novel antibacterial agents(antibacterial peptides,metal,and metal oxide nanoparticles)and emerging antibacterial methods(photothermal therapy and photodynamic therapy)for the control of drug-resistant bacteria infections has gradually evolved.Compared with antibiotics,the antibacterial mechanisms of these methods are complex,and drug-resistant bacteria can be effectively eliminated without specific targets.However,there are also have some disadvantages that cannot be ignored,such as certain cytotoxicity,material instability,easy agglomeration,poor light stability,and difficult temperature control.Therefore,it is crucial for wound management to develop a safe and efficient treatment method that can quickly clear the infection of drug-resistant bacteria after injury.Based on the above research background,this paper proposes to use the porphyrinic Metal-Organic Frameworks(MOFs)as photosensitizers.Relying on the characteristics of the powerful expansion of electrospinning technology and the advantages of the unique structure of the nanofibers prepared by this technology,we proposed to use nanofibers as the substrate,via co-electrospinning and polyphenol-mediated two methods to achieve MOFs modified on the surface of nanofibers.Explore the optimization criteria of the ~1O₂ production capacity of nanofiber membranes,to achieve the function of efficiently killing drug-resistant bacteria.The research conclusions are divided into the following three main points:(1)The porphyrinic MOFs nanoparticles(PCN-224 NPs)were successfully synthesized by introducing photosensitizers into the MOFs framework structure through a solvothermal method.The synthesized MOFs nanoparticles showed a spherical shape with homogeneous size and good dispersion.The porphyrin ligand has a complete structure and is effectively dispersed in the framework structure of MOFs nanoparticles,and its photostability is improved.MOFs nanoparticles have a good ability to produce ~1O₂.(2)PCN-224 NPs were introduced into polycaprolactone(PCL)nanofibers by co-electrospinning technology to prepare composite nanofibrous membranes with photodynamic activity.The surface morphology,~1O₂ generation performance,particle distribution,antibacterial performance,and cytotoxicity of PCL nanofibrous membranes loaded with different concentrations of PCN-224 NPs were systematically evaluated.The results show that the composite nanofibrous membranes have the best ~1O₂ production capacity and antibacterial performance when the doping concentration is 25 wt%,and the biocompatibility is good.(3)On this basis,it is proposed to use polyphenolic coating(TBA)as a mediating layer to load PCN-224 NPs on the surface of PCL nanofibers to achieve a significantly enhanced ~1O₂production capacity.The results show that PCN-224 NPs can be firmly bonded to the surface of PCL nanofibers through TBA coating,and the ability to produce ~1O₂ is significantly enhanced.And based on the synergistic antibacterial effect of TBA and PCN-224 NPs,it can effectively kill Methicillin-resistant Staphylococcus aureus.In vivo wound healing tests further prove that the composite nanofibrous membranes can effectively kill bacteria in the wound and promote the healing of wounds infected by drug-resistant bacteria.