Coupled Antibacterial Effects of Plasma-Activated Water and Pulsed Electric Field

Abstract

In the biomedical applications of cold plasma, the dominant biological effect is most typically attributed to the reactive oxygen and nitrogen species (RONS), while the physical effect of electric fields is sometimes overlooked. Here, we investigated the antibacterial effect of RONS in plasma-activated water (PAW) on the inactivation of E. coli bacteria, coupled with a mild 200-nanosecond pulsed electric field (PEF) treatment. By using transient spark discharge plasma in open atmospheric air and closed air reactors, and by adding hydrogen peroxide (H2O2) into the PAW, different chemical compositions of RONS were obtained. We measured the time evolution of the concentrations of key species in the PAW post-discharge: nitrites (NO2−) and H2O2. PAW rich in both NO2− and H2O2 showed an antibacterial effect, which was enhanced by the PEF, whereas PAW rich in NO2− and poor in H2O2 showed an enhancement of the antibacterial effect by the PEF only when H2O2 was externally added. The presence of sufficient concentrations of both NO2− and H2O2 optimized the formation of peroxynitrous acid (ONOOH), which caused a strong peroxidation of the cell membranes leading to the cell death, but it also made them more vulnerable to the PEF treatment. The results suggest that the interaction with radicals during the bacteria exposure to PAW leads to an antibacterial effect reinforced by the pulsed electric field, hence showing a synergy of the chemical and physical plasma agents. This opens new perspectives for applications both plasma and PEF areas of research.

Efficacy of argon cold atmospheric pressure plasma jet on hospital surface decontamination and its impact on the surface property

“…As a result, the cell's structural integrity would be compromised, leading to cell wall breakdown and membrane poration or permeabilization. Consequently, the influx of these RONS and ions into the cell via membrane pores would destroy intracellular components involving DNA denaturation, protein oxidation, etc [24,26,30,37,64,71,72]. Thus, the identified gas phase species might be involved in bacterial inactivation via oxidative and electrostatic stress.…”

An effective sanitizer for fresh produce production:In situplasma activated water treatment inactivates pathogenic bacteria and maintains the quality of cucurbit fruit

“…To further investigate the unique antimicrobial properties of the in situ DBDD-PAW system, we simulated the local electric field distribution and polarization on bacterial cells in solution and on the cucamelon surface. Intense local electric fields are shown to contribute to the antimicrobial power of in situ PAW systems via membrane damage and electroporation (31). We hypothesise that ·O 2 − and/or downstream reactive species combined with the membrane damage induced by electric fields and polarization lead to the antimicrobial activity observed in this system.…”

An Effective Sanitizer for Fresh Produce Production: In Situ Plasma-Activated Water Treatment Inactivates Pathogenic Bacteria and Maintains the Quality of Cucurbit Fruit

“…2 ). Intense local electric fields are shown to contribute to the antimicrobial power of in situ PAW systems via membrane damage and electroporation ( 31 ). We hypothesize that ·O 2 − and/or downstream reactive species, combined with the membrane damage induced by electric fields and polarization, lead to the antimicrobial activity observed in this system.…”