The Synergistic Mechanism Of Hydrophilic ZnO Nanoparticle And Cold Atmospheric Plasma Against Staphylococcus Aureus

Bacterial infectious diseases are a global health problem.With the large-scale use of antibiotics,a mass of drug-resistant bacteria have emerged,and more and more refractory infections have been reported.Cold atmospheric plasma(CAP)and Zinc Oxide nanoparticles(Zn O NPs)have been developed,independently and along their own routes,to address the same set of challenges in biomedicine.The biological effects of Zn O NPs are derived from the active substances produced by its photocatalysis,as well as the targeting and permeability in tissues,but its biological cytotoxicity is still an uncertain factor.The biological effect of CAP comes from the charged particles,excited atoms and molecules,various active substances,ultraviolet rays,free electrons and other components produced by its high ionization,but their interactions with living tissues are usually local and their penetration capacity is limited.The limitation problem also provides a new research direction for developing new sterilization methods,reducing the use of antibiotics,and effectively inhibiting the production of drug-resistant strains.In this study,the common pathogenic Staphylococcus aureus(S.aureus)was used as the experimental object.Through the study of the synergistic bactericidal mechanism of CAP and Zn O NPs,it is expected to solve the biological cytotoxicity of Zn O NPs and the limitations of scope of CAP in biomedicine,then provide more opportunity for developing new sterilization methods,reducing the use of antibiotics,and effectively inhibiting the production of drug-resistant strains.The following is the main research contents in the study.Firstly,the bactericidal effect and mechanism of amino-functionalized hydrophilic Zn O(AH-Zn O)against S.aureus.It is detected that the intracellular ROS level,cell membrane potential,cell apoptosis characteristics and morphology of S.aureus treated with AH-Zn O.The results showed that AH-Zn O was firmly adsorbed on the surface of S.aureus due to electrostatic interaction between AH-Zn O and S.aureus.And AH-Zn O could improve intracellular ROS level,reduce the cell membrane potential and induce the cell apoptosis of S.aureus.Second,The sterilization effect and synergistic mode of CAP combined with AH-Zn O against S.aureus.The combination index(CI)of the combination antibacterial effect of CAP and AH-Zn O was analyzed via the Chou-Talalay method to conclude the synergistic mode.The results showed that CAP and AH-Zn O have the stronger synergistic sterilization effect in short time.Thirdly,the synergistic sterilization mechanism of CAP and AH-Zn O on S.aureus.It is detected that the intracellular ROS level,cell membrane potential,apoptosis characteristics,cell morphology and internal structure of S.aureus treated combined with CAP and AH-Zn O.In addition,after CAP discharge treatment,the ORP,p H and RONS in AH-Zn O solution and the absorption spectra of AH-Zn O solution were quantitatively measured.The results showed that the concentration of AH-Zn O is high,the main synergistic mechanism with CAP is that CAP enhanced the sterilization effect of AH-Zn O and promoted the occurrence of apoptosis of S.aureus.And the concentration of AH-Zn O is low,the main synergistic mechanism is that AH-Zn O promoted the production of RONS in AH-Zn O solution discharge treated with CAP and enhanced the bactericidal effect of CAP against S.aureus.