He-Plasma Jet Generation and Its Application for E. coli Sterilization

Abstract

Atmospheric pressure plasma jet (APPJ) is a promising technique for the sterilization of pathogenic microorganisms in an ambient environment. In this work, a helium-APPJ was generated by double dielectric barrier discharge and applied to the sterilization of model microorganism in air and water. Discharge characteristics (including waveform and frequency of applied voltage), jet properties (such as feed gas flow rate, jet length, thermal effect, and optic emission spectra), and sterilization performance (in terms of clear/sterilized area, size of plaques, and sterilization efficiency) were investigated. Homogeneous helium plasma jet was generated in an energy-efficient way (18 kHz, 6 kV, 0.08 W) with a 19 mm jet and limited heating. The He-APPJ achieved good sterilization performances within very short treatment time (as short as 30 s). For surface sterilization, the area of clear zone and size of the plaque were 1809 mm2 and 48 mm, respectively, within 5 min treatment. For water sterilization, 99.8% sterilization efficiency was achieved within 5 min treatment. The optic emission spectra suggest that active species such as excited molecules, ions, and radicals were produced in the He-APPJ. The as-produced active species played important roles in the sterilization process.

Simultaneous degradation of glucocorticoids and sterilization using bubbling corona discharge plasma based systems: A promising terminal water treatment facility for hospital wastewater

“…All the above data indicate that PBCD-based treatments are effective in sterilization. It has been proven that reactive nitrogen radicals (RNS) and reactive oxygen radicals (ROS) produced by NTP can disrupt cells and their contents, leading to bacterial inactivation or even death [25] , [38] . What played a decisive role will be discussed in the following sections.…”

“…By detecting the emission spectrum of the PBCD reactor with OES, a series of RNS and ROS were observed [17] , [25] . RNS mainly refer to the strong emission of the second positive ion system of N 2 molecules (N 2 (C-B)) at 300 – 400 nm [17] .…”

“…NOγ bands in the range of 200–300 nm also appeared [17] . These excited metastable free radicals collide with microbial cells in the solution, causing the cell membrane to deform and malfunction, which eventually cause perforation [25] . In addition, the charged electrons and ions will collide with the GC molecules in the solution, breaking chemical bonds and completing the degradation of GCs [25] .…”

“…E. coli (CGMCC 1.1512) cultured in Luria-Bertani medium was used as a model microorganism to evaluate the bactericidal effects of the PBCD-based system. The density was determined by OD 600 and the heterotrophic plate-counting method [25] . Two hundred millilitres of E. coli solution (10 9 CFU/mL) was sterilized under the corresponding conditions for GC removal.…”

Study on Active Particles in Air Plasma and Their Effect on α-Amylase

“…The application of plasma technology is growing as theoretical studies into plasma physics and plasma chemistry become more in-depth. Plasma presents a highly excited unstable state, which contains a large number of high-energy electrons, ions, molecules, neutral atoms, excited state atoms, photons, and radicals [ 1 , 2 , 3 ]. The plasma transforms the electrical energy from the power source into various forms of energy such as light, sound, electricity, and chemistry.…”