Low temperature plasma-based sterilization: Overview and state-of-the-art

Low temperature, high pressure, non-equilibrium plasmas are now routinely used in several material processing applications, and in some cases are competing with low pressure plasmas in areas where these have historically been dominant. Etching and deposition are examples of such applications. Amongst the novel applications of non-equilibrium plasmas, biomedical applications such as electrosurgery, surface modification of biocompatible materials, and the sterilization of heat-sensitive medical tools are particularly interesting. In this paper, first a brief overview of recent research on reduced-pressure plasma-based sterilization/ decontamination methods is given. Then a detailed review and discussion on the effects of atmospheric pressure non-equilibrium plasmas on the cells of bacteria is presented. This includes the evaluation of the inactivation kinetics and the roles of the various plasma agents in the inactivation process. Measurements of the plasma temperature, the UV emission, and concentrations of various reactive species for the case of air plasma are presented. Plasma sub-lethal effects are also briefly discussed, and the prospects of the use of "cold" plasmas in the biomedical field are outlined.