Physical and biological mechanisms of plasma interaction with living tissue

Summary form only given: The number of potential applications of non-equilibrium nonthermal atmospheric pressure discharges in biology and medicine has grown significantly in the recent years. The plasma science community is looking closely at medical applications of various plasma systems. For example, use of plasma in treatment of dental cavities, sterilization of various surfaces, treatment of skin diseases, delicate surgeries, and many other applications. It is now clear that these plasmas can have not only physical (i.e. burning the tissue), but a medically relevant therapeutic effect- plasmas can trigger a complex sequence of biological responses in tissues and cells. To move ahead in further development of actual commercial tools that will enter the hospital, and in finding novel, and perhaps even unexpected, uses of these plasmas and understanding of mechanisms of interaction of non-equilibrium gas discharge with living organisms becomes essential. It is our goal to attempt an understanding of mechanisms of interaction of plasma with living tissues and cells. Clearly, these mechanisms depend on the way the plasma is generated, the way it is delivered, and the organism it is delivered to; i.e. radiofrequency discharge in helium will likely have somewhat different mechanisms of interaction than afterglow from a nitrogen arc. We attempt to classify different types of species created in plasma and assess their importance in achieving desirable effect. As the system readily available to us is the floating electrode dielectric barrier discharge (FE-DBD), we will use it as example plasma; however, we will attempt to be more general in our task of understanding the mechanisms. We will present different types of plasmas we use for treatment of living tissues and cells followed by discussion of physical and then biological mechanisms of interaction.