HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Copyright
The pathway of the biologically active molecule hydrogen peroxide (H 2 O 2 ) from the plasma generation in the gas phase by an atmospheric pressure argon plasma jet, to its transition into the liquid phase and finally to its inhibiting effect on human skin cells is investigated for different feed gas humidity settings. Gas phase diagnostics like Fourier transformed infrared spectroscopy and laser induced fluorescence spectroscopy on hydroxyl radicals ( • OH) are combined with liquid analytics such as chemical assays and electron paramagnetic resonance spectroscopy. Furthermore, the viability of human skin cells is measured by Alamar Blue ® assay. By comparing the gas phase results with chemical simulations in the far field, H 2 O 2 generation and destruction processes are clearly identified. The net production rate of H 2 O 2 in the gas phase is almost identical to the H 2 O 2 net production rate in the liquid phase. Moreover, by mimicking the H 2 O 2 generation of the plasma jet with the help of an H 2 O 2 bubbler it is concluded that the solubility of gas phase H 2 O 2 plays a major role in generating hydrogen peroxide in the liquid. Furthermore, it is shown that H 2 O 2 concentration correlates remarkably well with the cell viability. Other species in the liquid like • OH or superoxide anion radical (O •− 2 ) do not vary significantly with feed gas humidity.
This paper presents a combined 2D numerical and experimental study of the influence of N 2 admixture on the dynamics of a He-N 2 discharge in the 10 cm long dielectric tube of a plasma gun set-up. First, the comparison between experiments and simulations is carried out on the ionization front propagation velocity in the tube. The importance of taking into account a detailed kinetic scheme for the He-N 2 mixture in the simulations to obtain a good agreement with the experiments is put forward. For the μs driven plasma gun, the two-and three-body Penning reactions occurring in the plasma column behind the ionization front, are shown to play a key role on the discharge dynamics. In the experiments and simulations, the significant influence of the amplitude of the applied voltage on the ionization front propagation velocity is observed. As the amount of N 2 varies, simulation results show that the ionization front velocity, depends on a complex coupling between the kinetics of the discharge, the photoionization and the 2D structure of the discharge in the tube. Finally, the time evolution of axial and radial components of the electric field measured by an electro-optic probe set outside the tube are compared with simulation results. A good agreement is obtained on both components of the electric field. In the tube, simulations show that the magnitude of the axial electric field on the discharge axis depends weakly on the amount of N 2 conversely to the magnitude of the off-axis peak electric field. Both, simulations and first measurements in the tube or within the plasma plume show peak electric fields of the order of 45 kV•cm −1 .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.