Understanding the Role of Plasma Bullet Currents in Heating Skin to Mitigate Risks of Thermal Damage Caused by Low-Temperature Atmospheric-Pressure Plasma Jets
Shunya Hashimoto,
Hideo Fukuhara,
Endre J. Szili,
Chiaki Kawada,
Sung-Ha Hong,
Yuta Matsumoto,
Tatsuru Shirafuji,
Masayuki Tsuda,
Atsushi Kurabayashi,
Mutsuo Furihata,
Hiroshi Furuta,
Akimitsu Hatta,
Keiji Inoue,
Jun-Seok Oh
Affiliations
Shunya Hashimoto
Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan
Hideo Fukuhara
Department of Urology, Kochi Medical School, Kochi University, Kochi 783-8505, Japan
Endre J. Szili
Future Industries Institute, University of South Australia, Adelaide, SA 5095, Australia
Chiaki Kawada
Department of Urology, Kochi Medical School, Kochi University, Kochi 783-8505, Japan
Sung-Ha Hong
Future Industries Institute, University of South Australia, Adelaide, SA 5095, Australia
Yuta Matsumoto
Graduate School of Engineering, Osaka Metropolitan University, Osaka 558-8585, Japan
Tatsuru Shirafuji
Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan
Masayuki Tsuda
Division of Laboratory Animal Science, Life and Functional Materials, Kochi Medical School, Kochi University, Kochi 783-8505, Japan
Atsushi Kurabayashi
Department of Pathology, Kochi Medical School, Kochi University, Kochi 783-8505, Japan
Mutsuo Furihata
Department of Pathology, Kochi Medical School, Kochi University, Kochi 783-8505, Japan
Hiroshi Furuta
Department of Electronic & Photonic Systems Engineering, Kochi University of Technology, Kochi 782-8502, Japan
Akimitsu Hatta
Department of Electronic & Photonic Systems Engineering, Kochi University of Technology, Kochi 782-8502, Japan
Keiji Inoue
Department of Urology, Kochi Medical School, Kochi University, Kochi 783-8505, Japan
Jun-Seok Oh
Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan
Low-temperature atmospheric-pressure plasma jets are generally considered a safe medical technology with no significant long-term side effects in clinical studies reported to date. However, there are studies emerging that show plasma jets can cause significant side effects in the form of skin burns under certain conditions. Therefore, with a view of developing safer plasma treatment approaches, in this study we have set out to provide new insights into the cause of these skin burns and how to tailor plasma treatments to mitigate these effects. We discovered that joule heating by the plasma bullet currents is responsible for creating skin burns during helium plasma jet treatment of live mice. These burns can be mitigated by treating the mice at a further distance so that the visible plasma plume does not contact the skin. Under these treatment conditions we also show that the plasma jet treatment still retains its medically beneficial property of producing reactive oxygen species in vivo. Therefore, treatment distance is an important parameter for consideration when assessing the safety of medical plasma treatments.
