Reactive Molecular Dynamics Simulation On Mechanism Of Interaction Between Atmospheric Plasmas And Molecular Structures Of Cell

Cold Atmospheric Plasma(CAP)has many advantages,such as high efficiency,low energy consumption,safety,reliability,pollution-free and can be directly used in biological tissues.It has a broad application prospect in the field of biomedicine.Among them,the active components play a key role in the interaction with biological tissues.However,it is difficult to explore the microscopic mechanism of the interaction between plasma active components and organisms by current experimental detection methods.Therefore,it is particularly important to study the interaction mechanism between CAP and biological cells from the molecular biology level.Based on this,the effect of active particles is characterized on the micro-level.The role of active components in the sterilization process is explored from the perspective of chemical reaction.And a series of functional and structural changes occur within the bacteria after plasma treatment.This is conducive to the development and improvement of CAP sterilization technology and related sterilization mechanism.Three main contents in this paper are as follows:(1)This paper summarizes the application background of CAP in biomedical field.The research status of CAP sterilization at home and abroad and the sterilization mechanism inferred from experiments are analyzed.The feasibility of exploring the micromechanism of sterilization in the field of biomedicine.Based on the simulation software Material Studio,the molecular structure of the system model is created and optimized,which lay the foundation for the related research of reaction molecular dynamics simulation.(2)The destructive effects of different ROS(O,OH,HO2,H2O2)on SCG molecules of yeast cell wall skeleton structure are investigated by using the method of reaction molecular dynamics simulation.The results show that the hydrogen capture reaction between ROS and SCG result in the breakage of chemical bonds(C-O,C-C)in the structure,which lead to the destruction of yeast cell wall.Among them,0 and OH attract H atoms in the structure with high activity,easily breaking C-C bonds and monosaccharides in the dextran branched chain;HO2 and H2O2 are dehydrogenate by the structure,and the reaction efficiency is high.They are easy to break C-O bonds,mainly by breaking the glycoside bonds to disintegrate the chain structure of dextran.The destruction paths of various ROS in different positions of SCG structure are described.It is found that monosaccharide structure was more easily destroyed than glycoside bond.Through data analysis,the characteristics and effects of different ROS on SCG damage are compared.Among them,the activity of O is the strongest,followed by OH,and the activity of HO2 and H2O2 is weaker due to different ways of action.Moreover,the conversion between ROS will affect the reaction efficiency to a certain extent.The simulation results are verified with the experimental phenomena,and the microscopic mechanism of ROS destroying fungal cell wall in plasma is explained at atomic level.(3)The reaction of OH radicals with PNAG molecules of Staphylococcus aureus membrane skeleton structure is simulated by molecular dynamics with different concentrations(i.e.5,10,20,30,40,50).It is found that OH radicals not only destroy chemical bonds and lead to the breakage of PNAG molecular structure,but also adsorb on PNAG molecules to form new chemical structures.With the increase of OH radical concentration,the reaction efficiency increases first and then decreases.At the same time,many new reaction paths destroying monosaccharides appear in the simulation.When the concentration of OH reaches 50.it destroyes the glycoside bond.Moreover.the breakage of C-C bond increases rapidly and then slowly,while that of C-O bond increases slowly and then rapidly.But the number and proportion of C-C.bond breakage are much higher than that of C-O bond.And C-N bond is hardly damag,ed by OH.The adsorption reaction between OH and structure is mainly located in the R group.especially-NH2.With the increase of OH concentration.the adsorption of OH on the glycoside bond occurs.A comprehensive study of the reaction path and efficiency of ROS interaction with biological structure at the atomic level can provide micro-theoretical guidance for the correlation between experimental parameters and experimental results.It will guide the application of plasma in biomedical field and promote the development of plasma medicine research.