Atmospheric Pressure Single Electrode Argon Plasma Jet for Biomedical Applications

Atmospheric pressure single electrode argon /oxygen plasma jet has been generated between a high-voltage electrode and the surrounding room air for treating thermally sensitive materials is reported. The discharge has been characterized by electrical and optical emission spectroscopic technique. The microplasma jet device operated by an electrical power less than 10 W exhibited a long plasma jet of about 8.0 cm with temperature near 300 K, not causing any harm to human skin. Optical emission spectra measured in the range of 200–900 nm showed that various reactive species such as O, OH, N +, Ar etc., are present in the plasma plume. Optical emission spectrometry has been used for the determination of electron temperature (Te) and electron density (ne) of the produced plasma. The analyses provided that electron density and electron temperature vary with plasma jet length. This plasma jet has been applied for inactivation of prokaryotic cells (Escherichia coli, Staphylococcus aureus) and eukaryotic cells (Candida albicans, Saccharomyces cerevisae) to obtain >4 log10 reduction in E. coli and < 2,000 cells reduction in eukaryotic microalgae C. vulgaris, operating at a voltage of 3.5 kV, frequency of 27 kHz and gas flow rate of 2 L/min at jet. We also investigated the effect of plasma jet in pH and temperature of cell culture medium to demonstrate that plasma species are solely responsible for inactivating living cells.