Atmospheric pressure plasma jets interacting with liquid covered tissue: touching and not-touching the liquid

Abstract

In the use of atmospheric pressure plasma jets in biological applications, the plasma-produced charged and neutral species in the plume of the jet often interact with a thin layer of liquid covering the tissue being treated. The plasma-produced reactivity must then penetrate through the liquid layer to reach the tissue. In this computational investigation, a plasma jet created by a single discharge pulse at three different voltages was directed onto a 200 µm water layer covering tissue followed by a 10 s afterglow. The magnitude of the voltage and its pulse length determined if the ionization wave producing the plasma plume reached the surface of the liquid. When the ionization wave touches the surface, significantly more charged species were created in the water layer with H 3 O + aq , O 3 − aq , and O 2 − aq being the dominant terminal species. More aqueous OH aq , H 2 O 2aq , and O 3aq were also formed when the plasma plume touches the surface. The single pulse examined here corresponds to a low repetition rate plasma jet where reactive species would be blown out of the volume between pulses and there is not recirculation of flow or turbulence. For these conditions, N x O y species do not accumulate in the volume. As a result, aqueous nitrites, nitrates, and peroxynitrite, and the HNO 3aq and HOONO aq , which trace their origin to solvated N x O y , have low densities.

A Comparison of Floating-Electrode DBD and kINPen Jet: Plasma Parameters to Achieve Similar Growth Reduction in Colon Cancer Cells Under Standardized Conditions

“…Methods to directly detect short-lived species in tissues are currently unavailable. Modeling studies suggest that plasma in direct contact with a target alters species deposition and cell membrane oxidation [101][102][103]. Experimentally, plasma-derived oxidants have been shown to be deposited on cells and liquids through plasma-treated agarose membranes [104] and micropores [105], which may facilitate the deciphering effects of jet plasma short-lived species in cells.…”

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

“…Furthermore, with a higher absorption of higher energy photons, more photochemical processes occur along the photon pathway. During treatment of liquids with the kinpen, a gradient of evaporating liquid from the bulk can be expected, 29 so that the atmosphere surrounding the plasma plume becomes humidified. This humidity has an influence on the H 2 O 2 and • OH generation.…”

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

“…12 It is commonly agreed that reactive oxygen and nitrogen species (ROS and RNS) generated in the active plasma, its afterglow, or at the liquid interface play a major role in creating biological effects of cold plasmas. 7,13 A multitude of oxygen and nitrogen centered radicals have been detected in the gas phase using highly quantitative and selective spectroscopic methods such as laser induced fluorescence and molecular beam mass spectrometry. 14,15 The liquid phase chemicals induced by the plasma in the solution are primarily investigated by indirect methods including electron spin resonance, colorimetric or fluorescence techniques, which can disturb the system under investigation and/or be highly nonselective.…”