Morphological and chemical changes of aerosolized E. coli treated with a dielectric barrier discharge

Abstract

This study presents the morphological and chemical modification of the cell structure of aerosolized Escherichia coli treated with a dielectric barrier discharge (DBD). Exposure to DBD results in severe oxidation of the bacteria, leading to the formation of hydroxyl groups and carbonyl groups and a significant reduction in amine functionalities and phosphate groups. Near edge x-ray absorption fine structure (NEXAFS) measurements confirm the presence of additional oxide bonds upon DBD treatment, suggesting oxidation of the outer layer of the cell wall. Electron microscopy images show that the bacteria undergo physical distortion to varying degrees, resulting in deformation of the bacterial structure. The electromagnetic field around the DBD coil causes severe damage to the cell structure, possibly resulting in leakage of vital cellular materials. The oxidation and chemical modification of the bacterial components are evident from the Fourier transform infrared spectroscopy and NEXAFS results. The bacterial reculture experiments confirm inactivation of airborne E. coli upon treating with DBD.

Cold atmospheric plasma inactivation of aerosolized microdroplets containing bacteria and purified SARS‐CoV‐2 RNA to contrast airborne indoor transmission

“…[ 8,17 ] However, the efficacy of treatments depends on genome structure of the pathogens and their replication machinery [ 18 ] ; furthermore, new technologies must take into account the possibility that both bacteria and viruses could develop harmful mutagenic outcomes associated with multiple transition mutations across the genome when they are underexposed or undergo insufficient inactivation treatments. [ 18,19 ]…”

“…It is shown that a 1.5‐ and 5.5‐log reduction of the airborne Escherichia coli are achieved, respectively, after single plasma exposure of 10 s and 2 min. [ 19,28 ] Another study demonstrated that NTP generated by a wire‐to‐plate type DBD reactor induces a significant inactivation of both Bacillus subtilis ‐ and Pseudomonas fluorescens‐ containing bioaerosol. [ 2 ] Park et al [ 1 ] used a different kind of DBD architecture to effectively inactivate Staphylococcus epidermidis bioaerosols using a short residence time (0.24 s).…”

“…[ 2 ] Park et al [ 1 ] used a different kind of DBD architecture to effectively inactivate Staphylococcus epidermidis bioaerosols using a short residence time (0.24 s). Romero‐Mangado et al [ 19 ] studied the effect of DBD on aerosolized E. coli concluding that the cell structure is damaged to a varying extent and severe oxidation of the cell membrane is found, establishing effective inactivation of the bacteria. Romero‐Mangado et al [ 29 ] also demonstrated the possibility to inactivate bioaerosol containing S. epidermidis or Aspergillus niger , respectively, a Gram‐positive bacteria and fungal spores by means of CAP treatment.…”

Simultaneous bacterial inactivation and degradation of an emerging pollutant under visible light by ZnFe2O4co-modified with Ag and rGO

“…There was a decrease in the peak intensity and slight shi towards the higher wavenumber in the region between 3700 and 3500 cm À1 , which could be assigned to the free -OH group. [49][50][51] Signicant disorder was observed in the 3000-2800 cm À1 region, demonstrating that fatty acids of various membrane components were reduced and transformed. 50 The peaks at 1645 and 1550 cm À1 due to the presence of amide I and amide II bands of proteins and peptides shied to the lower wavenumbers 1640 and 1548 cm À1 , respectively, indicating changes in the protein structures aer the treatment.…”

Efficacy of atmospheric pressure dielectric barrier discharge for inactivating airborne pathogens

“…Previous work using the DBD system was focused on Escherichia coli, a Gram-negative bacteria. 14 The distinctive difference between Gram-negative and Gram-positive bacteria is the presence of a thick peptidoglycan outer layer on Gram-positive bacteria whereas Gram-negative bacteria have a thin peptidoglycan structure. The mentioned study concluded that E. coli cell structure was damaged to varying extent and a severe oxidation of the cell membrane was found, establishing effective inactivation of the bacteria.…”