This study investigated the use of glutathione as a marker to establish a correlation between plasma parameters and the resultant liquid chemistry from two distinct sources to predefined biological outcomes. Two different plasma sources were operated at parameters that resulted in similar biological responses: cell viability, mitochondrial activity, and the cell surface display of calreticulin. Specific glutathione modifications appeared to be associated with biological responses elicited by plasma. These modifications were more pronounced with increased treatment time for the European Cooperation in Science and Technology Reference Microplasma Jet (COST-Jet) and increased frequency for the dielectric barrier discharge and were correlated with more potent biological responses. No correlations were found when cells or glutathione were exposed to exogenously added long-lived species alone. This implied that short-lived species and other plasma components were required for the induction of cellular responses, as well as glutathione modifications. These results showed that comparisons of medical plasma sources could not rely on measurements of long-lived chemical species; rather, modifications of biomolecules (such as glutathione) might be better predictors of cellular responses to plasma exposure.
Developing a low‐cost depyrogenation process is vital in extending the medical applicability of polymers that can be used in medicine. We present an overview of the plasma‐based depyrogenation literature and address the need to develop a nonthermal plasma‐based depyrogenation process for delicate materials such as chitosan. We present a low‐cost plasma apparatus to treat chitosan powder in hermetically sealed bags. We decouple the experiments into two parts: depyrogenation experiments for dried standard endotoxin on glass slides and analysis of chitosan modifications through Fourier‐transform infrared spectroscopy. We demonstrate depyrogenation efficacy with up to a 4‐log reduction in endotoxin levels and discuss minor changes observed in plasma‐treated chitosan.
Surface Dielectric Barrier Discharges (SDBDs) have been gaining interest in recent years for numerous applications. One of the advantages of SDBDs is their scalability and flexibility of materials used, allowing larger electrodes than simple linear electrodes investigated in earlier works. This paper seeks to elucidate the properties of more complicated SDBD geometries utilizing differing repeated lattice structures. Voltage and current traces, optical emission spectroscopy, digital imaging, and numerical analysis are used to analyze the electrodes. Reduced electric fields obtained through optical emission spectroscopy and the total power deposited into the plasma are presented. The reduced electric field is not significantly affected by increasing applied voltage, but minor variations could be observed due to the geometry of the electrode lattice structures. Finally, it was observed that plasma power is not a simple linear relationship in these more complicated lattice structures. Smaller lattice structures were observed to have lower energy deposited per period.
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