Effect of discharge parameters and surface characteristics on ambient-gas plasma disinfection

Ambient-gas plasma, or plasma created from air at ambient conditions, has been studied as a means of disinfecting surfaces. However, the parameters that determine the effectiveness of plasma disinfection are not well understood. We report results from surface disinfection experiments and determine the characteristics that are responsible for the antimicrobial effect against the model bacterium Escherichia coli. Our results suggest that neutral reactive species are more influential in surface disinfection than charged particles. In addition, non-biological surfaces are easier to disinfect than pig skin. Air plasma performed comparably to conventional antiseptics, indicating that ambient-gas plasma treatment could be a promising strategy for both clinical and community infection control. Ambient-gas plasma can inactivate bacteria on surfaces, but its efficacy depends both on the nature of the discharge and the type of surface being disinfected. Under our conditions, inactivation is modulated by reactive neutral species, not ions or electrical effects. Most "non-biological" surfaces are comparatively easy to disinfect, but it is much more difficult to disinfect pig skin.