Sterilization of Escherichia coli O157:H7 using micro corona ionizer

Abstract

We demonstrated in vitro sterilization of Escherichia coli O157:H7 bacteria on agar by a pin-between-planes micro corona ionizer. The gap between the pin and the grid was similar to 1.1 mm, the length of the grid was similar to 2.1 mm and the height was similar to 1.0 mm. The effective pin radius and discharge length were both approximated to be 200 mu m. Ozone generation rates of similar to 2.3 x 10(-3) mg/s, similar to 2.7 x 10(-3) mg/s and similar to 3.5 x 10(-3) mg/s at 1,500 V were calculated for relative humidity (RH) of 35 %, 25 % and 10 % respectively. Analytical ozone generation rate increases as RH decreases and it is consistent with experimental observations. Using target and control petri dishes with E. coli plated agar, the sterilization capability of the micro corona ionizer at 37 A degrees C for 24 h was evaluated. A similar to 60 % reduction in bacterial colony was shown with plate counting and its kill radius could be tuned from similar to 20 mm to similar to 5 mm by reducing the duty cycle from 100 % to 50 % with 30 min pulse width. The results suggested that the micro corona ionizer might be suitable as a tunable ozone source in wound dressing for chronic wound management.