Cold Atmospheric Plasmas in Biology and Medicine: The Fundamentals

Cold atmospheric plasmas (CAP) sources have recently been playing an important role in various biomedical applications, which include the killing of pathogenic bacteria and viruses, the destruction of cancer cells and tumors, and the enhancement of wound healing via disinfection and proliferation of healthy cells¹. It has been shown that the biological effects of CAP are mostly mediated by the reactive oxygen and nitrogen species, ROS/RNS. These include O, OH, H₂O₂, O₃, O₂^-, O₂(¹Δ), NO, ONOO^-. The generation and transport of these reactive species proceed in several stages. Charged particles and other atomic and molecular reactive species are first produced in the main plasma ignition region. These species are then transported in the plasma afterglow, interact in a gas-liquid interface, until finally reaching their biological targets, such as cells and tissues. Both ROS and RNS possess strong oxidative properties and can trigger signaling pathways in biological cells. Therefore, delivering controllable doses of these species to cells and tissues can lead to specific biological outcomes including the onset of apoptosis, enhancement or suppression of cell proliferation, modified cell migration, etc. The ability to modulate cell behavior has crucial implications in various CAP biomedical applications such as wound healing and cancer treatment. In this paper the fundamental scientific basis of the application of CAP to cells and tissues is discussed and some applications in select healthcare therapies are presented.

¹ M. Laroussi, X. Lu, and M. Keidar, “Perspective: The Physics, Diagnostics, and Applications of Atmospheric Pressure Low Temperature Plasma Sources Used in Plasma Medicine”, J. Appl. Phys. 122, 020901 (2017).