| The widespread and growing distribution of foodborne diseases,most of which are caused by a small number of pathogenic bacteria,is a global public health concern.Bacterial infections caused by foodborne pathogens have always been one of the causes that threaten human health.The conventional treatment strategy is antibiotic therapy,but with the excessive use or abuse of antibiotics,bacteria have developed a certain degree of drug resistance.Photodynamic therapy(PDT)generates reactive oxygen species(ROS)through the excitation of photosensitizer,which has a strong killing effect on bacteria without causing drug resistance.It has the advantages of high efficiency,safety,and easy to implement.In this study,based on the unique structure and visible light-triggered properties of the porphyrin metal-organic framework PCN-224,vancomycin-loaded composite nanomaterials Van/PCN were prepared,and PCN-224 nanoparticles were loaded onto the nanofiber membrane polyacrylinitrile(PAN)by electrospinning technology.A PAN-PCN nanofiber membrane with photodynamic bactericidal function was prepared.The antibacterial properties of the two antibacterial materials were analyzed by various techniques and their antibacterial mechanisms were discussed..(1)A composite nanomaterial Van/PCN was prepared based on a porphyrin metal-organic framework(PCN-224)by loading vancomycin(Van).The function and properties,bactericidal mechanism,destruction of bacterial biofilm and biocompatibility were studied.The results showed that the nanoparticles of the prepared nanomaterials Van/PCN were relatively spherical,the loading efficiency of Van was 9.8%,and had good dispersibility.Van was continuously released from the nanomaterials Van/PCN over time,and more than 40% was released after 24 h.The prepared nanomaterials Van/PCN have the ability to produce ROS,and when exposed to visible light Van/PCN,they produce ROS and kill bacteria,achieving a synergistic antibacterial effect with Van.In the Van/PCN+L group,the bacterial cells collapsed and shrank seriously,the surface was rough,the edge of the bacteria was partially dissolved,the permeability of the bacterial membrane increased,the membrane potential changed,the extracellular protein content increased,and the integrity of the cell membrane was significantly damaged.Van/PCN combined with visible light irradiation has excellent anti-biofilm performance,and has no cytotoxicity within a certain concentration range,which has good biocompatibility.The photoresponsive composite nanomaterials Van/PCN achieved high efficiency and broad-spectrum antibacterial properties,and showed good effects in bactericidal and biofilm removal,while reducing the toxic side effects compared with the single phototherapy mode.The results of this study provide a new strategy for the design of nanomaterials with high antibacterial efficiency and biosafety.(2)A photodynamic bactericidal nanofiber film PAN-PCN was prepared by electrospinning polyacrylonitonitrile(PAN)combined with PCN-224.The results showed that after 30 min of light treatment,the inhibition rates of Escherichia coli and Staphylococcus aureus treated with PAN-PCN reached 99.5% and 99.7%,respectively,and the growth curve of bacteria entered the logarithmic growth phase later than other groups.It has a strong bactericidal effect on gram-positive bacteria(S.aureus)and gram-negative bacteria(E.coli).PAN-PCN treatment resulted in damage to the integrity of bacterial membrane.Under visible light irradiation,PAN-PCN increased bacterial membrane permeability,changed bacterial membrane potential,and promoted bacterial death.The prepared nano-cellulose film PAN-PCN has a certain antibacterial effect on fresh-cut lotus root and has a certain application prospect in food fresh-preservation.Photodynamic nanofiber membrane(PAN-PCN)provides a theoretical basis for the production and application of new food plastic preservation film due to its excellent antibacterial properties. |
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