Construction Of Photoelectric Material And Antibacterial Mechanism

With the rapid development of society,environmental problems have been paid more and more attention.Bacteria are widely found in nature’s water and soil,the hospital environment,threatening human health,including Acinetobacter baumannii and E.coli and so on.Photoelectrocatalytic technology can be used to solve the problem of environmental pollution and solar energy has become popular.The most prominent of these is the photoelectrocatalyst,which has good antibacterial properties.However,the photoelectrocatalytic sterilization mechanism is still less of further investigation.The purpose of this paper is to make photoelectrocatalytic sterilization to be more widely applied to the bactericidal mechanism.The research work is mainly divided into the following aspects.（1）Study on antibacterial mechanism of Cu_xO/TiO₂@Cu network as different electrodes in photoelectrocatalytic process Cu_xO/TiO₂@Cu net was synthesized by supercritical alcohol-thermal method using copper nitrate as copper source and tetrabutyl titanate as titanium source.The catalyst was used as cathode and anode to kill Escherichia coli,respectively.For the study of antimicrobial mechanism,we studied the reactive oxygen species（ROSs）detection,the leakage of K⁺,malondialdehyde（MDA）concentration,DNA analysis,RNA analysis,protein analysis and apoptosis detection.The mechanism of photoelectrocatalysis was discussed in the aspects of the change of defense enzyme activity and the degree of bacterial mineralization.In general,the antibecterial activity of anode was better than cathode.The anodic antibacterial process was dominated by oxidation with photo-induced holes acted as the main active species to destroy the cell membrane including loss of cell membrane integrity and increased permeability,which was reflected by the leakage of K⁺and the production of MDA（malondialdehyde）.Then protein and Catalase（CAT）were found to be oxidatively damaged due to the h⁺and·OH^-attack.Meanwhile,electrons performed better in reducing the Superoxide Dismutase（SOD）and decomposing the protein into NH₄⁺in cathodic cell than that in in amodic cell.（2）Preparation and application of ZnO Nanoneedle/ZIF-67 photoelectrocatalyst loaded on cobalt foilAfter the holes were etched on the Co sheets by electrochemical etching,the etched Co sheets were added into the precursor solution of dimethyl imidazole and Co（NO₃）₂.6H₂O mixed in methanol to grow ZIF-67.After that,perpendicular ZnO nanoneedles were grown on the surface of cobalt sheets.The cobalt sheets loaded with ZnO nanoneedle/ZIF-67 were applied to photoelectrocatalytic antibacterial process.ZnO nanoneedles could puncture and fix the bacteria.In addition,the porous MOF and the pores of cobalt sheet were used to effectively adsorb bacterial fragments.The hydrogen bonding between ZIF-67 and bacteria can effectively prolong the contact time between the bacteria and the catalyst to achieve the goal of completely mineralizing the bacterial structure.（3）Synthesis and application of ZIF-67 coated CoO Nanoneedles in photoelectrocatalytic Antibacterial processMetal-organic frameworks（MOFs）and related materials are attracting considerable attention for their applications in gas storage/separation as well as catalysis.Meanwhile,there is still a problem that bacterial cell membrane hinders the contact between carriers and biomass and genetic material in the photoelectrocatalytic antibacterial process,which makes the antibacterial effect not ideal.In this paper,we proposed a simple strategy to fabricate metal oxide semiconductor@MOF core-shell nanoneedles,and successfully obtained freestanding CoO@ZIF-67 nanorods.In this synthetic process,CoO nanorods not only act as the template but also provide Co²⁺ions for the formation of ZIF-67.