Dry Bio-Decontamination Process in Reduced-Pressure O2 Plasma

Hongxia Liu,Xin Ma,Chi He,Xinxin Feng,Jinzhuo Xie

doi:10.3390/app9091933

Abstract

The main objective of this work was to fully understand the bio-decontamination process in a reduced-pressure oxygen plasma. Gram-negative Escherichia coli species was chosen as the target microorganism in this test. The comparison of decontamination efficacy between plasma total and UV radiation individually under various treatment parameters and tests of DNA agarose electrophoresis were made to evaluate the inactivation effect of UV radiation. The quantity of protein leakage and the concentration of malondialdehyde (MDA), which are markers of the end products of lipid peroxidation, in bacterial suspension after treatment were determined to estimate the contribution of both charged particles and free radicals for bacterial death. In addition, a scanning electronic microscope was used to visualize the plasma effect on microorganisms. The results showed that the essential action of the oxygen plasma on Escherichia coli is believed to be attributed to the fast and intense etching on cell membrane by electrons and ions. Attacks on polyunsaturation fatty acid (PUFA) in the cell membrane by oxygen free radicals and the destruction of the DNA in the cell by UV radiation are accessorial during an effective decontamination process.

Highlights

The elimination of disease-causing agents from the surfaces of equipment, which can sometimes be challenging to fulfill without using toxic materials or high temperatures, is an absolutely necessary requirement in many fields
E. coli 8099 slant lawn incubated at 37 ◦ C for 24 h was oscillated and eluted by phosphate buffer solution (PBS), the eluent was diluted to form certain concentration suspensions of bacilli
The decontamination efficiency of oxygen plasma total and UV radiation individual was investigated at the same operation parameters, respectively, from E as functions of plasma RF power, treatment time and gas flow rate

Summary

Introduction

The elimination of disease-causing agents from the surfaces of equipment, which can sometimes be challenging to fulfill without using toxic materials or high temperatures, is an absolutely necessary requirement in many fields. Both methods suffer from drawbacks such as exposure to extremely high temperatures (>1000 ◦ C) in the case of autoclaves, and toxic exposure in the case of EtO Another concern with the latter is the long aeration process which, importantly, creates a serious threat for both personnel and the environment [1]. Do affect only slightly the bulk material, are environmentally sound, do not produce toxic by-products, and are fast and cost-effective This kind of method is regarded as a green technique and even as the most promising bio-decontamination technique [2,3,4]

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