Destruction of biological particles using non-thermal plasma.
Mechanism of inactivation of bio-particles exposed to non-thermal plasma (NTP), namely, dielectric barrier discharge (DBD), and plasma jet (PJ), has been studied usingE. coli,B. subtilisspore,S. cerevisiaeand bacteriophages. States of different biological components were monitored during the course of inactivation. Analysis of green fluorescent protein, GFP, introduced intoE. coli. orB. subtilesspore cells proved that radicals generated by NTP penetrate into microbes, destroying the cell membrane and finally damage the genes. We have evaluated the damage of the bacteriophages. Bacteriophage λ having double stranded DNA was exposed to DBD, then DNA was purified and subjected toin vitroDNA packaging reactions. The re-packaged phages consist of the DNA from discharged phages and brand-new coat proteins were proved to be active, indicating that the damage of coat proteins is responsible for inactivation. M13 phages having single stranded DNA were also examined with the same manner. In this case, damage to the DNA was as severe as that of the coat proteins. For practical applications, DBD showed very intense sterilization ability forB. Subtilisspore with the D-value of less than 10 s. This result indicates a possibility of application of NTP for quick sterilization.
Toyohashi University of Technology, 1-1 Hibarigaoka, Tenpaku-cho, Toyohashi, Aichi 441-8580, Japan.
Akira
A
Mizuno
dielectric barrier discharge; non-thermal plasma; plasma jet; radical; sterilization