In the past years, the plasma community witnesses a fast development of bio-medical applications
(see the section 2),
since cold plasmas provide multiple agents that can efficiently kill bacteria and other hazardous microbes.
In biomedical applications, the fundamental research to assess the roles of various plasma agents involved is very important. At present, the major role in atmospheric pressure plasmas generated in air is typically attributed to reactive oxygen and nitrogen species (RONS). The aqueous RONS are formed from dissolved NO, NO2, O3 and OH radicals generated by the plasma in the gas phase.
Depending on the used electrical discharge, different gaseous products can dominate in the treated air. For example, the ozone generation is very efficient by cold plasma sources, such as dielectric barrier or streamer corona discharges.
We also studied ozone generation using pulsed discharges and streamer corona.
Thermal plasma sources, and microwave discharges, on the other hand, can generate significant amounts of nitrogen oxides. However, new types of discharges optimized for bio-medical plasma applications are still being developed and studied.
We are focusing now at the synthesis of NO, NO2 and their precursors (O and N radicals) by the transient spark (TS) discharge in air.
Our research confirmed high reactivity of the plasma generated by the TS, and its antimicrobial activity.
In dry synthetic air, the TS leads to the formation of NOx: the sum of NO and NO2 densities more than 600 ppm was achieved with power input below 6 W (NOx generation rate
∼7×1016 molecules/J). In future, we also plan to optimize the NOx production by varying parameters of the electric circuit (external resistor, internal capacitor, distance of electrodes).
More details in:
Machala Z., Tarabová B., Hensel K., Špetlíková E., Šikurová L., Lukeš P.: Formation of ROS and RNS in Water Sprayed through Transient Spark Discharge in Air and Their Bactericidal Effects, Plasma Process. Polym. 10 (7), 649-659 (2013). abstractdownloadcitations: 87
Hensel K., Machala Z., Tardiveau P.: Capillary Microplasmas for Ozone Generation, Eur. Phys. J. Appl. Phys. 47 (2), 22813 (2009). abstractdownloadcitations: 13
Pawłat J., Hensel K., Ihara S.: Generation of Oxidants and Removal of Indigo Blue by Pulsed Power in Bubbling and Foaming Systems, Czech. J. Phys. 56, B1174-B1178 (2006). abstractdownloadcitations: 2
Janda M., Martišovitš V., Hensel K., Machala Z.: Generation of antimicrobial NOx by atmospheric air transient spark discharge, Plasma Chem. Plasma Proc. 36, 767-781 (2016). abstractdownloadcitations: 8