Characterization of non-thermal atmospheric pressure helium plasma jet for biomedical applications

In this work, an atmospheric pressure plasma jet generated in a dielectric barrier discharge (DBD) configuration with He and He/O₂ mixture has been characterized using electrical and optical emission spectroscopy (OES) diagnostics. A visible plasma plume length of approx. 33 mm was generated using a 60 kHz AC power supply. The discharge characteristics in the active and afterglow region of the plasma jet that are critical for biomedical applications have been investigated. Atomic and molecular lines of selected reactive plasma species that are considered to be u seful to induce biochemical reactions in biomedical applications such as OH transition at 308 nm and OH transition at 287 nm, O I transition 3p⁵P→3s⁵S⁰ at 777.41 nm, O I transition 3p³P→3s³S⁰ at 844.6 nm, N₂(C-B) second positive system (SPS) with electronic transition in the range of 300-450 nm and N₂⁺(B-X) first negative system (FNS) with electronic transition at 391.4 nm have been studied. The OH rotational temperatures that are equal to gas temperatures was measured based on the fitting of experimental spectra on to simulated spectra of the plasma jet. Our results show that, in the entire active plasma region, the gas temperature remains at 380 K and it increases to 400 K in the afterglow region of the plasma jet. In conclusion, the plasma jet produces significant reactive species while gas temperature remains cold and therefore it can be applied to a range of biomedical applications¹².