Characteristics Of Atmospheric Pressure Plasma Jet And Application In Cell Protection

Atmospheric pressure plasma jet(APPJ)has recently emerged as an effective tool in the field of “plasma medicine” due to its several advantages including easy operation,high reaction efficiency,environmental friendly,low gas temperature,amenability to temperature-sensitive material,and so on.According to previous studies,the neuroprotective effects of APPJ have been discovered against oxidative stress-induced injuries on SH-SY5 Y cells,which was related to the APPJ-induced nitric oxide(NO)accumulation.However,the effects of APPJ on other injuries have not been reported.In this thesis,AC-driven He-APPJ is used on hypoxic injured neurons.after investigation of cell viability,cell morphology and the content of NO and ROS,we explain the protection mechanism of APPJ on hypoxia induced SH-SY5 Y cells.The physical properties,discharge characteristics and development process of the jet are also investigated.There include two parts of experimental works in this thesis.First,the characteristics of atmospheric pressure plasma jet are measured.The development of plasma jet head is recorded by ICCD.The velocity of jet development under different applied voltage and power frequency is calculated accordingly.The results show that the jet speed would be faster and the maximum speed would increase with the increase of voltage and power frequency.The influences of discharge parameters on the jet characteristics are studied.The jet length increases with increasing voltage and flow rates,applied voltage and gas flow are the key factors that affect the jet length.But the jet length remains constant at different frequencies.NO emission spectrum shows that the highest intensity appears at the nozzle exit.The intensity weakens with the increase of distance from the nozzle.There exists a linear relationship between NO intensity values and power frequency and gas flow rates.However,relationship between the NO intensity and the applied voltage is uncertain.Second,the application of atmospheric pressure plasma jet in cell protection experiment is tested.SH-SY5 Y cells are adherently cultured,and then treated with APPJ for different times.Subsequently,cells are cultured in hypoxia for 5 hours and under anoxic condition for 24 hours.Related parameters are tested by various methods,including the cell morphology changes in real time by ECIS,cell apoptosis by LDH assay,the content of NO by Griess kit,and the content of ROS by Hydrogen Peroxide Assay Kit.It is shown that cells proliferate significantly after 20 hours hypoxia treatment,which could be inhibited by the 30 s APPJ treatment.After 24 hours hypoxia,cells membrane deformation and cells contract severely.Cell morphology could be improved by the APPJ treatment,after 24hours hypoxic exposure.The NO concentration increases significantly with the duration of APPJ treatment.It indicates that APPJ could protect SH-SY5Y cells from hypoxia-induced injuries,which may relate with NO accumulation.