Rapid Inactivation of Biological Species in the Air using Atmospheric Pressure Nonthermal Plasma

Abstract

Here, nonthermal plasma generated by a dielectric barrier discharge (DBD) system was applied to inactivating aerosolized Bacillus subtilis cells and Pseudomonas fluorescens as well as indoor and outdoor bioaerosols. The culturability, viability, and diversity losses of the microorganisms in air samples treated by the plasma for 0.06-0.12 s were studied using culturing, DNA stain as well as polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) methods. In addition, the viable fraction of bacterial aerosols with and without the plasma treatment was also quantified using qPCR coupled with ethidium monoazide (EMA). It was shown that less than 2% of B. subtilis aerosols survived the plasma treatment of 0.12 s, while none of the P. fluorescens aerosols survived. Viability tests, EMA-qPCR results, and Scanning Electron Microscopy (SEM) images demonstrated that both bacterial species suffered significant viability loss, membrane, and DNA damages. Exposure of environmental bacterial and fungal aerosols to the plasma for 0.06 s also resulted in their significant inactivations, more than 95% for bacteria and 85-98% for fungal species. PCR-DGGE analysis showed that plasma exposure of 0.06 s resulted in culturable bacterial aerosol diversity loss for both environments, especially pronounced for indoor environment. The results here demonstrate that nonthermal plasma exposure could offer a highly efficient air decontamination technology.

Optimization of Propidium Monoazide Quantitative PCR for Evaluating Performances of Bioaerosol Samplers for Sampling AirborneStaphylococcus aureus

“…Therefore, multiple PMA concentrations may have to be assessed and optimized before PMA-qPCR is used to define the bacteria viability in different applications. EMA, another DNA-intercalating agent, has been used at a concentration of 25 mg/ml to detect Legionella pneumophila (Chang and Chou 2011a,b) and at 100 mg/ml to detect Bacillus subtilis and Pseudomonas fluorescens in the air (Liang et al 2012). However, EMA can enter both viable and dead S. aureus at a concentration of 50 mg/ml (Kobayashi et al 2009a).…”

Bacterial inactivation by high-voltage atmospheric cold plasma: influence of process parameters and effects on cell leakage and DNA

“…; Liang et al . ), while others suggested no clear differences in inactivation by cold atmospheric plasma treatment in relation to cell wall structure (Klämpfl et al . ).…”

Assessment of Microbicidal Activity of Atmospheric Pressure Non- Thermal Plasma Against Planktonic and Biofilm Forms

“…There are many challenges in healthcare environment which consists of very vulnerable patients, inaccessible or challenging items of equipment to decontaminate and microbes that have adapted to be able to replicate and spread in this hospitable niche [7].…”