Impact of Microwave Plasma Torch on the Yeast Candida glabrata

Abstract

Recently, various cold plasma sources have been tested for their bactericidal and fungicidal effects with respect to their application in medicine and agriculture. The purpose of this work is to study the effects of a 2.45 GHz microwave generated plasma torch on a model yeast example Candida glabrata. The microwave plasma was generated by a surfatron resonator, and pure argon at a constant flow rate of 5 Slm was used as a working gas. Thanks to a high number of active particles generated in low-temperature plasma, this type of plasma has become highly popular, especially thanks to its bactericidal effects. However, its antimycotic effects and mechanisms of fungal inactivation are still not fully understood. Therefore, this study focuses on the antifungal effects of the microwave discharge on Candida glabrata. The main focus is on the measurement and evaluation of changes in inactivation effects caused by varying initial concentration of Candida glabrata cells, applied microwave power and exposure time. The discharge was applied on freshly inoculated colonies of Candida glabrata spread on the agar plates and its inhibitory effects were observed in the form of inhibition zones formed after the subsequent cultivation.

Effects of different cold atmospheric‐pressure plasma sources on the yeast Candida glabrata

“…The concentration of the active species is the highest at the tip of the plasma plume [26] and that is why the distance between the treated sample and the edge of the cavity (for both MW sources) was chosen in a way that the end of the plasma plume would touch the treated surface (see Table 1). The schematic setup and the discharge can be seen in Figure 1, and a detailed description with the diagnostics and other characteristics, including voltage, current, and reactive species analysis, can be found in Krcma et al and Trebulova et al [26,38] 2.1.2 | Unipolar MW torch (Surfayok) MWs generated by the same generator as in the case of the surface-wave MW torch and a power of 9-12 W are guided by a coaxial cable into the plasma generator, where they propagate in all directions and pass their energy to argon molecules, thus ionizing them. The plasma is formed in the cavity and is blown out in the form of a single plasma beam.…”

“…A detailed study on this issue was published recently. [38] F I G U R E 6 The inhibitory effects of the surface-wave microwave (MW) torch with the power of 12 W on three different concentrations of Candida glabrata: 10 7 CFU/mL, 10 6 CFU/mL, and 10 5 CFU/mL, after 48 h cultivation at 24°C.…”

Influence of Feeding Gases on the Composition of Plasma Activated Water

“…It was noted that usage of pure argon as career gas lead to sweeping in of molecules contained in the surrounding air (oxygen, nitrogen, water vapor, etc.) into the plasma flow wherein they were excited or ionized resulting in the presence of RONS such as nitrogen monoxide radical (NO), hydroxyl radical (OH), atomic oxygen (O), peroxynitrite molecule (ONOOH) or ozone (O3) in the plasma torch [11]. J Julák et al prepared PAW in the atmosphere of Ar, air, CO2 and N2.…”

Application of Plasma Technology in Bioscience and Biomedicine

“…The antimicrobial efficacy of cold plasmas and plasma-treated liquids is of interest in a variety of fields, ranging from the food industry [5] to the medical field [6][7][8][9].…”

“…The authors propose these as an innovative alternative to the sanitization processes currently used in production plants [6]. Also, on the topic of fungicidal effects, in the work by Trebulova et al the effects of a plasma torch on the inactivation of model yeast (Candida glabrata) provided insights into the effects of the reactive species from the plasma gas phase [7].…”