Antibacterial Mechanism Of Low-dimensional Nanostructured ZnO Crystals And Their Regulation Technology

As an inorganic antibacterial material that combines good environmental safety,high biocompatibility,and excellent antibacterial effect,ZnO has been widely used in production and life because of its many sources and low prices.In recent years,due to the continuous improvement in theoretical computing power and experimental optimization design in the field of materials,innovative researches on the preparation methods,antibacterial mechanisms and practical applications of zinc oxide materials have emerged in an endless stream.In order to make better use of the antibacterial advantages brought by the structural characteristics of zinc oxide materials,recent studies have tended to start from a finer crystal structure level,combined with more synergistic and diverse antibacterial mechanisms,supplemented by simpler and feasible Construct the process to design and obtain inorganic antibacterial materials with higher activity and stronger practicability.This thesis takes ZnO as the research object,focuses on the mechanism of its antibacterial activity in the absence of light,and the selective activation of molecular oxygen on different exposed crystals of ZnO,emphasizes the the relationship between active oxygen and chemistry generated by catalysis.For the problem that the active oxygen generated in practical applications is difficult to achieve rapid sterilization,the focus is also on the rapid physico-antimicrobial effect of bionic nanostructures,highlighting the sterilization rapidity and practicality of the substrate and its application.The specific work and main research results of this article include:1.From the perspective of DFT simulation calculation,the mechanism of ROS generation of ZnO in the absence of light was studied.The significant differences in bond length and state density(DOS)of O2 absorbed on different facets in its activation pathway were analyzed and discussed.We found for the first time that the complete crystal of ZnO has a pre-activation effect on O2 under dark conditions,Pre-activated as intermediate on the clean region of both facets first,O2 is reduced to O22-/H2O2 species by two-electron transfer on the OVs regions of{2110}-ZnO,and reduced to·O2 by single-electron transfer on the OVs regions of {1010}-ZnO.2.From the perspective of chemical experiments,it was further confirmed that ZnO with different specific exposed facets does have different molecular oxygen catalytic activities.In the absence of light,{2110}-ZnO produces more O22-/H2O2 in 4h than {1010}-ZnO.And due to the good bactericidal effect of ROS,the ZnO with {2110} has an antibacterial rate of greater than 99.99%against both E.coli and S.aureus.3.ZnO array was constructed in situ on the surface of various substrates,and the rapid physical sterilization effect was studied.The seed layer is preset by the pulling method and the dipping method respectively,and the two-step hydrothermal method is used in high temperature resistant hard materials such as stainless steel sheets,stainless steel mesh and aluminum sheets,as well as cotton fabrics,PET,PE,PP fibers and viscose cellulose and other flexible fiber materials have in-situ grown ZnO nanoarray structures.The antibacterial activity of related ZnO nanoarray samples by using the improved film method and the improved oscillation method for physico-antimicrobial surfaces testing.The results showed that the stainless steel mesh with the ZnO nanoarray had a greater antibacterial effect of than were both up to 99.99%against E.coli(Gram-negative bacteria)and S.aureus(Gram-positive bacteria).4.PDA,a kind of bionic mussel material,has strong adhesion to various substrate materials,and the complexation between its-NH2 group and Zn2+in the synthesis process of the ZnO nanoarray,making it enhance the binding force between the ZnO nanoarray and cotton fiber substrate.Compared with the sample without PDA deposition,the prepared ZnO nanoarray cotton fabric composite hybridized with PDA can still be effective against E.coli for a longer period of time after multiple washings.Colony count results and corresponding antibacterial ratio of ZnO samples were displayed greater than 99.99%.