Masaru Hori1
Nagoya University1
Researches on the application of non-thermal atmospheric pressure plasma to biotechnology fields such as medicine and agriculture have been actively conducted. In particular, plasma medicine is expected to create a new academic field from the viewpoint of fusion between plasma science and medicine, and at the same time has the potential to realize innovative treatment methods. It has been reported that non-thermal plasmas can provide new approaches to sterilization, wound healing, blood coagulation, cancer treatment, regenerative medicine, and immunotherapy. Therefore, many research projects on "plasma medicine and its innovation" are currently being conducted around the world. Our goal is to establish a theory of plasma medicine based on the internal parameters (particle parameters) of the plasma that are relevant to the physics and chemistry within the plasma. For this purpose, we analyze the reactions of plasmas in the gas phase, and then systematically clarify the interactions between plasmas and liquids. Finally, we aim to elucidate the molecular reactions in various cells and biological tissues induced by the reactive species generated in the liquid, with the aim of applying this knowledge to cancer treatment and other applications. The general scheme is to create a plasma source conducive to medicine, diagnose the plasma, and understand the interaction of the plasma with medical and biological targets. In particular, we focus on radical species in plasmas and analyze them based on radical reactions to seamlessly understand the reactions in the gas phase, liquid phase, and in vivo, and to create new medical treatments by controlling radicals.<br/>We have found that plasma-activated medium (PAM) and plasma-activated lactate Ringer's solution (PAL), synthesized by the reaction of radicals in plasma with organic solutions, selectively kill cancer against normal cells. These methods are called the indirect method because the plasma acts only to activate the solution and it is the active solution that acts on the organism. This plasma-activated solution has great potential in cancer treatment and is expected to be used in a wide range of medical applications. We have succeeded in PAM and PAL with high reproducibility by developing ultra-high density non-equilibrium atmospheric pressure plasma and controlling the active species in it with ultra-precision. By identifying the active species in them, we have elucidated the radical-induced biochemical reactions in intracellular signal transduction, genes, metabolism, and immune system. By doing so, we found that by controlling the radicals in the plasma, we can synthesize specific active species in the liquid, and these active species can seamlessly control specific radical reactions in the cell.<br/>In this presentation, I will systematically introduce a series of reactions up to the phenomenon of selective killing of cancer based on radicals, and propose the importance of plasma biology by controlling radicals, and look forward to the contribution of plasma to the permanent development of humanity.