Effective Fungal Spore Inactivation with an Environmentally Friendly Approach Based on Atmospheric Pressure Air Plasma

Abstract

Fungal contamination of surfaces is a global burden, posing a major environmental and public health challenge. A wide variety of antifungal chemical agents are available; however, the side effects of the use of these disinfectants often result in the generation of toxic residues raising major environmental concerns. Herein, atmospheric pressure air plasma generated by a surface barrier discharge (SBD) is presented as an innovative green chemical method for fungal inactivation, with the potential to become an effective replacement for conventional chemical disinfection agents, such as Virkon. Using Aspergillus flavus spores as a target organism, a comparison of plasma based decontamination techniques is reported, highlighting their respective efficiencies and uncovering their underpining inactivation pathways. Tests were performed using both direct gaseous plasma treatment and an indirect treatment using a plasma activated aqueous broth solution (PAB). Concentrations of gaseous ozone and nitrogen oxides were determined with Fourier-transform infrared spectroscopy (FTIR) and Optical emission spectroscopy (OES), whereas hydrogen peroxides, nitrites, nitrates, and pH were measured in PAB. It is demonstrated that direct exposure to the gaseous plasma effluent exhibited superior decontamination efficiency and eliminated spores more effectively than Virkon, a finding attributed to the production of a wide variety of reactive oxygen and nitrogen species within the plasma.

Cold atmospheric pressure plasma‐assisted removal of aflatoxin B1 from contaminated corn kernels

“…The decontamination capacity of CAP created in the form of SBD in the air is mainly attributed to the highly reactive CAP chemistry and CAP‐induced UV irradiation. As proven in our previous research, [ 11c,13 ] CAP‐generated RONS are the most important part of the degradation processes. According to the numerical model presented by Hasan and Walsh, [ 9a,14 ] the reformation of CAP RONS chemistry takes place with the distance from the SBD electrode.…”

Sterilization in liquids by air plasma under intermittent discharge

“…O, N, • OH, O 2 -, HO 2 , O 3 , H 2 O 2 , NO x , and ONOOwere said to play an extremely important role in the sterilization of spores (Hojinik et al, 2019). However, the concentrations of H 2 O 2 , NO 2 -, and O 3 , which had half-lives of several tens of minutes and below several tens of mg/L, were too low to inactivate the spores in water (Hayashi et al, 2012).…”

“…O also had a lifetime of milliseconds (Hayashi et al, 2012). • OH and H 2 O 2 were produced by reaction (1), (2) (Hojinik et al, 2019), (3) and (4) (Dobrynin et al, 2014).…”

“…Peroxynitrite has a lifetime of 1 second (Kirsch et al, 1998); it penetrated the cell membrane, reached the cytology site, was a powerful oxidant, and was thought to contribute greatly to sterilization. (Hojinik et al, 2019).…”

Piezoelectric Direct Discharge: Devices and Applications

“…Control of fungal plant pathogens [136] (e.g., Aspergillus flavus by surface barrier discharge [137]).…”