Abstract

Reactive oxygen and nitrogen species (RONS) generated by medical gas plasmas are considered major mediators of plasma-induced biological effects. This includes the atmospheric pressure argon plasma jet kINPen routinely used in clinical applications. The jet’s biomedical action has been shown to be tailored by modifying its feed gas. However, a systematic comparison of how feed gas composition and humidity shape plasma chemistry remains lacking, which would shift application-specific plasma chemistries from guessing to designing. In this study, we systematically investigated, compared, and statistically related 65 individual feed gas conditions of the kINPen argon plasma jet by increasing O2, N2, and combined O2 + N2 admixtures under dry and humidified conditions. Plasma gas phases were assessed using optical emission spectroscopy and reactive species produced in liquid via hydrogen peroxide, nitrite, and nitrate quantification. O2-containing admixtures generally reduced overall plasma emission and liquid-phase RONS accumulation, whereas N2-containing admixtures preferentially enhanced nitrogen-associated emission features. Water vapor addition via the admixture gas stream acted as an important secondary tuning parameter, exerting the strongest effects under combined O2 + N2 conditions. Multivariate analyses confirmed clear separation of chemistry profiles according to feed gas composition and humidity, while correlation and regression analyses identified several condition-dependent relationships between gas-phase emissions and liquid-phase reaction products. These data provide a comprehensive characterization of kINPen plasma chemistry under controlled feed gas modification and establish a reference framework for tailoring plasma-derived reactive species profiles in future plasma biology and medicine studies.

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