Plasma Chemistry in Aqueous Solutions

When plasmas are used for plasma redox biology, in most cases an aqueous liquid medium is present between the plasma and the living matter. The presence and composition of a liquid medium can drastically impact the resulting plasma-produced reactive oxygen and nitrogen species (RONS) delivered to the biological substrate. In addition, several treatment approaches are based on the application of plasma-treated liquids. Hence, understanding the interaction of plasmas with liquids and the resulting RONS is a critical step towards a detailed understanding of plasma redox biology. This chapter summarizes our current understanding of plasma chemistry in an aqueous solution relevant to plasma redox biology. We introduce the basics of plasma-liquid interactions and the key impact of the transport of gas-phase reactive species through solutions and how this transport is impacted by the treatment modality. In addition, we provide an overview of the major chemical mechanisms that have been found to play a key role in plasma redox biology. We conclude with a brief overview of the state of the art in the quantification of RONS in solution and relevant modeling.