Nanosecond Pulsed Discharge Plasma And Its Applications In Skin Medicine

In recent years,plasma medicine has become an innovative and emerging field which combining electric engineering,plasma physics,analytical chemistry,life science and clinical medicine.In a general perspective,plasma medicine can be subdivided into two principal approaches.?1?using plasma techniques to treat surfaces,materials or devices to realize sterilization for subsequent special medical applications,and?2?plasma treatment on the human?or animal?body to realize therapeutic effects based on direct interaction of plasma with living tissue.Atmospheric pressure cold plasma generated by pulsed discharging contains various active substances,so it is widely applied in the plasma medicine.In this paper,we designed a nanosecond pulsed power supply and atmospheric pressure cold plasma generator.We change different work source gases to selective product active substances,so as to research their contribution in specific biomedical applications.In this work,an all-solid-state high voltage repetitive pulsed-power modulator was designed based on Marx generator,magnetic compression circuit and pulse transformer.The 6-stage Marx generator based on power MOSFET output the primary pulse voltage with the peak voltage of-5 kV,pulse edge 50 ns,minimum pulse-width 200 ns,repetitive frequency up to 10 kHz.Through the single-stage magnetic switch compression circuit and pulse transformer,the modulator output narrower and higher pulse voltage.Finally we get the high-voltage pulse with the amplitude of 15 kV,rise time 25 ns,pulse-width 35 ns under a 20 k?resistor load.This designed pulsed-power modulator can greatly meet the discharge requirements of resistive-capacitive load.It can drive different structure types of discharge device which applied in the different application field,it can produce room-temperature plasma which can be safely touched by living body.Disinfection is the most extensive research direction in the application of plasma medicine.This paper introduces the sterilization effect of methicillin-resistant staphylococcus aureus?MRSA?suspension using atmospheric pressure cold plasma that discharged by different gas mixture,we find the different work gases discharge can produce different kinds of active substances,and its corresponding sterilization effec t is also different.With the study of sterilization mechanism,we find the reactive nitrogen oxides RONS play the major role of sterilization effect.At the same time,plasma generated ClO^-and HClO while dealing with physiological saline bacteria suspens ion also have certain sterilization effect.This paper introduces the atmospheric pressure cold plasma discharged by different gas mixture treats mice allergic contact dermatitis?ACD?model,and we found that humid Ar+H₂O discharged plasma treatment in mice ACD showed obvious therapeutic effect.At the same time,we treated different degree inflammation of the ACD model,For mild or moderate ACD models,only after one or two times 1-minute-treatment by Ar+H₂O plasma,ACD symptoms have significantly red uced.Even with ulcers of serious ACD,Ar+H₂O plasma treatment approach to show good therapeutic effect,and all the cases can accelerate the healing of ACD damage.Further experiments show that activity of hydrophilic H_x O_y particles generated in the humid plasma can accumulate and penetration into the subcutaneous tissue of mice,and interacts with inflammatory cel s,eventually reduce inflammation and promote the healing of dermatitis.