From RONS to ROS: Tailoring Plasma Jet Treatment of Skin Cells

Abstract

Finding a solution for air species contamination of atmospheric pressure plasmas in plasma medical treatment is a major task for the new field of plasma medicine. Several approaches use complex climate chambers to control the surrounding atmosphere. In this paper, ambient species are excluded in plasma-human-skin-cell treatment by ensheathing the plasma jet effluent with a shielding gas. Not only does this gas curtain protect the plasma jet effluent from inflow of air species but it also, more importantly, allows controlling the effluent reactive species composition by adjusting the mixture of the shielding gas. In the present investigations, the mixture of nitrogen to oxygen within the gas curtain around an argon atmospheric pressure plasma jet (kinpen) is varied. The resulting reactive plasma components produced in the jet effluent are thus either oxygen or nitrogen dominated. With this gas curtain, the effect of reactive oxygen species (ROS) and reactive nitrogen species (RNS) on the cell viability of indirectly plasma-treated HaCaT skin cells is studied. This human keratinocyte cell line is an established standard for a skin model system. The cell viability is determined by a fluorometric assay, where metabolically active cells transform nonfluorescent resazurin to the highly fluorescent resorufin. Plasma jet and gas curtain are characterized by numerical flow simulation as well as by optical emission spectroscopy. The generation of nitrite within the used standard cell culture medium serves as a measure for generated RNS. Measurements with the leukodye dichlorodihydrofluorescein diacetate show that, despite a variation of the shielding gas mixture, the total amount of generated reactive oxygen plus nitrogen species is constant. It is shown that a plasma dominated by RNS disrupts cellular growth less than a ROSdominated plasma.Index Terms-Atmospheric pressure plasma jet, gas curtain, plasma liquid interaction, plasma medicine, reactive nitrogen species (RNS), reactive oxygen plus nitrogen species (RONS), reactive oxygen species (ROS), skin cells.

Non-thermal plasma treatment induces MAPK signaling in human monocytes

“…Additionally, H 2 O 2 increased the relative phosphorylation of MEK 1/2 (1.8-fold) and ERK 1/2 (1.3-and 1.4-fold), consistent with Bhatt et al, who showed that ERK 1/2 can be induced in human monocytes by exogenous reactive oxygen species such as H 2 O 2 [28]. Since H 2 O 2 is generated in plasma-treated liquids, it is hypothesized to be one of the species activating the MEK-ERK pathway [29].…”

Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

“…Additionally, we found that the trend of VUV induced oxygen free radicals in complex liquids and the inhibition of human skin cells' viability 42 shows exactly the contrary behavior in dependency of the surrounding atmosphere. Thus, it can be claimed that the VUV generated ROS in the liquid are not the dominating species for inhibition of skin cell viability.…”

Identification of the biologically active liquid chemistry induced by a nonthermal atmospheric pressure plasma jet

“…This is an expected result and correlates well with the known chemistry of jet based plasmas and their interaction with liquids. 37,48 However, the impact of these nitrogen species on cell proliferation rate is limited. Sodium nitrite did not affect HaCaT cell proliferation rates up to 2000 lM under test conditions [ Fig.…”