Comparison of Sterilizing Effect of Nonequilibrium Atmospheric-Pressure He/O₂ and Ar/O₂ Plasma Jets

Abstract

The sterilizing effect of the non-equilibrium atmospheric pressure plasma jet by applying it to the Bacillus subtilis spores is invesigated. A stable glow discharge in argon or helium gas fed with active gas (oxygen), was generated in the coaxial cylindrical reactor powered by the radio-frequency power supply at atmospheric pressure. The experimental results indicated that the efficiency of killing spores by making use of an Ar/O2 plasma jet was much better than with a He/O2 plasma jet. The decimal reduction value of Ar/O2 and He/O2 plasma jets under the same experimental conditions was 4.5 seconds and 125 seconds, respectively. It was found that there exists an optimum oxygen concentration for a certain input power, at which the sterilization efficiency reaches a maximum value. It is believed that the oxygen radicals are generated most efficiently under this optimum condition.

Exploring the potential of cold plasma therapy in treating bacterial infections in veterinary medicine: opportunities and challenges

“…For example, when the exposure distance was increased from 0.5 cm to 2 cm in the case of air CAPJ, Pedroni et al (64) observed a reduction in the log colony-forming unit (CFU) reduction value from 2.5 to approximately 1.2. Therefore, the decline in CP's antimicrobial activity with an extended exposure interval, as reported by Pedroni et al (64) and Shouzhe and Jinpyo (63), may be attributed to a decrease in the concentration of active species during CP, as suggested by Lotfy et al (65).…”

“…The distance between the nozzle of the CAPJ and the sample is a crucial factor that impacts the effectiveness of CP in combating microbes. Studies by Sharma et al (62) and Shouzhe and Jinpyo (63), have shown that increasing the exposure distance leads to a decrease in the antimicrobial effect. For example, when the exposure distance was increased from 0.5 cm to 2 cm in the case of air CAPJ, Pedroni et al (64) observed a reduction in the log colony-forming unit (CFU) reduction value from 2.5 to approximately 1.2.…”

Cold Atmospheric Pressure Plasma: A Growing Paradigm in Diabetic Wound Healing—Mechanism and Clinical Significance

“…Thus, to have a successful CAP treatment, one should know the gas flow rate at which the most reactive species concentrate. Also, some reports have shown that the antimicrobial efficacy of CAP treatment is decreased by increasing the CAP exposure distance because the concentration of reactive species is reduced as a result of the short lifetime [64,77], meaning that some of them are annihilated before reaching the sample. The other factor that affects antimicrobial efficacy is the CAP treatment time.…”