Plasma formation using a capillary discharge in water for biotechnological applications

The present work reports plasma creation by means of a specially designed underwater discharge system and investigates the sterilization of E. coli by using the system. The underwater plasma was formed from a tungsten electrode inserted in a narrow dielectric capillary, producing a plasma by electrical breakdown. This produced various reactive plasma species from dissociation of water vapor; there species contain atomic oxygen, atomic hydrogen, and hydroxyl radicals. These are wellknown to be very helpful to sterilize microorganisms in water. The disinfection test comfirmed that the underwater discharge was effective in killing E. coli , showing a define D -value of 2.8 s.