Non-equilibrium atmospheric pressure plasmas interacting with biological matter offer a unique source of highly reactive chemistry beneficial for many applications including food decontamination, wound healing and cancer treatment. Many of these applications require controlled and selective interactions. For example, in decontamination processes, the inactivation of bacteria on healthy tissue or food samples needs to occur with minimized off target effects. Controlling selectivity requires a detailed understanding of the underlying plasma-bio-interaction mechanisms. As the majority of these plasma-bio interactions occur in an aqueous environment, linking plasma-produced reactive species in this environment with biological responses is of key importance to develop controlled and selective applications of plasmas in biomedical applications.
My group, in collaboration with microbiologists, has investigated the reactive species responsible for plasma-induced liquid phase processes such as the inactivation of bacteria and virus and the interaction of plasma with mammalian cells using a well-characterized atmospheric pressure plasma jet with a known composition of the reactive species in the gas phase. As in several other reports we found the importance of long-lived species such as H2O2 and OCl-. However many results indicated the direct or indirect importance of short-lived species. We will discuss these results in detail illustrating the unique character of the plasma treatment and also outline the strong possible sensitivity of plasma-bio interactions on treatment modalities.
This work is partially supported by the United States Department of Energy, Office of Fusion Energy Science (DE-SC0001319 and DE-SC0016053), the National Science Foundation (PHY 1500135) and the US Department of Agriculture, National Institute of Food and Agriculture (2017-67017-26172).