Study on surface sterilization of remote argon plasma

The germicidal effect (GE) and kinetics of Staphylococcus aureus by remote argon plasma are investigated, and the inactivation mechanism combining with the distribution of reactive species in the whole plasma field is discussed. The results show that the germicidal effect strongly depends on the experimental conditions, and with exposure time increasing, the kill rate slowers with three different segments. The effective inactivation appears within the distance of 0-30 cm (GE is no less that 99.9%) with the process parameters as follows: RF power of 100 W, time of 240 s, gas flow of 20 cm³/min, and pressure of 22 Pa. When the ionization degree of argon gas is sufficient under high power, the effectiveness of the remote argon plasma sterilization is believed to be attributed to the intense etching action on cell materials, which is initiated by discharge particles (electrons and Ar ions), the bombardment by free radicals is subsidiary. UV radiation in the plasma is the primary reason of bacterial inactivation under lower power.