Basic Reflections on Cold Atmospheric Pressure Plasma Therapy

Abstract

When a pure gas or gas mixture is passed through an electrical field, of fixed or alternating amplitude, cold plasma is produced. Cold plasma is a charged gas that consists of electrons, radicals, ions and high energy light photons. It includes and has been compared to reactive oxygen and reactive nitrogen species using gas chromatography and emission spectroscopy. It is applied directly to disease sites such as cancerous lesions, bacterially infected wounds, and burns. There are two cold atmospheric pressure plasma device types. With indirect discharge, the active plasma species are carried by a gas flow from the discharge arcs. In direct discharge, the sample is one of the electrodes as an active part of the discharge. In indirect discharge, the sample is treated with a plasma jet. With direct discharge, the cold atmospheric pressure plasma will not be generated until the sample is close enough to the electrode. Therefore, the plasma jet device may be suitable for treating a small area on a sample, while, in contrast, the dielectric barrier discharge may be more suitable for a more intense treatment on a large area of a sample. Indirect treatment with cold atmospheric pressure plasma is achieved by application of a liquid medium, in which the components of the plasma are dissolved by first applying the plasma jet to the liquid medium. Antibacterial, antifungal, and antiviral applications have been reported, including SARS-CoV-2 viral and pneumococcus bacterial infections. Reports on combinations with photodynamic therapy are increasing.