In the last two decades, non-equilibrium, low temperature, atmospheric pressure plasmas have gained acceptance as an attractive technological solution in industrial applications such as the surface modification of polymers. This is because of the ability of non-equilibrium plasmas to achieve enhanced gas phase chemistry without the need for elevated gas temperatures. In these plasmas the chemistry is driven by the energetic electrons, while the heavy particles remain at low energy. This low temperature feature of non-equilibrium plasmas makes them a very attractive technology in applications requiring medium preservation and where surface chemistry is desired but without damage to the bulk of the material under treatment. Biomedical applications are amongst these.

Preliminary research is showing promising possibilities to use low temperature plasmas in medical applications such as wound healing, tissue engineering, surface modification of biocompatible materials, and the sterilization of reusable heat-sensitive medical instruments. However, before any of these exciting possibilities become reality, an in-depth understanding of the effects of plasma on the cellular and sub-cellular levels has to be achieved.

In this lecture, a review of the knowledge that has been gained during the last few years will be presented. First an overview of research efforts on the inactivation of bacterial cells will be presented. This includes the evaluation of the inactivation kinetics and the roles played by the various plasma agents (such as UV photons and free radicals) in the inactivation process. The second part of this lecture deals with plasma sub-lethal effects on both prokaryotic and eukaryotic cells. Application to wound healing will be particularly highlighted.