Bacterial sterilization by a dielectric barrier discharge (DBD) in air

Abstract

a b s t r a c tCold atmospheric plasma treatment of microorganisms and living tissues has become a popular topic in modern plasma physics and in medical science. The plasma is capable of bacterial inactivation and noninflammatory tissue modification, which makes it an attractive tool for treatment of skin diseases, open injuries and dental caries. Because of their enhanced plasma chemistry, Dielectric Barrier Discharges (DBDs) have been widely investigated for some emerging applications such as biological and chemical decontamination of media at ambient conditions. Despite the high breakdown voltage in air at atmospheric pressure, the average current of DBD discharges is low. Therefore, a DBD can be applied in direct contact with biological objects without causing any damage. In this work a 60 Hz DBD reactor, which generates cold atmospheric plasma inside Petri dishes with bacterial culture, is investigated. Samples of Staphylococcus aureus, a Gram-positive bacterium and Escherichia coli a Gram-negative bacterium were selected for this study. The bacterial suspensions were evenly spread on agar media planted in Petri dishes. The reactor electrodes were placed outside the Petri dish, thus eliminating the risk of samples microbial contamination. The covered Petri dish with agar medium in it serves as dielectric barrier during the treatment. The plasma processing was conducted at same discharge power (∼ 1.0 W) with different exposure time. Sterilization of E. coli and S. aureus was achieved for less than 20 min. Plasma induced structural damages of bacteria were investigated by Scanning Electron Microscopy.

Efficacy of Different Carrier Gases for Barrier Discharge Plasma Generation Compared to Chlorhexidine on the Survival of <b><i>Pseudomonas aeruginosa</i></b> Embedded in Biofilm in vitro

“…Possibly, the admixture of 1% O 2 quenches the excited Ar species [55] and inhibits secondary plasma products which are important for potential antimicrobial effects against P. aeruginosa . Otherwise, on scanning electron images, some other authors have shown cell detritus after plasma treatment [40,56,57]. It may well be that an increased O 2 concentration accelerates microbial cell damage, which may result in a plasma shadow effect by accumulated cell detritus.…”

Study of the Influence of Variation in Distances Between Electrodes in Spectral DBD Plasma Excitation

“…Plasma species is one of the key parameters, because it influences the amount of species obtained as well as the energy consumed during the treatment of materials, such as film deposition 7,8 , surface sterilization 9 , polymers surface treatment 9 , dental and skin treatments 10 . This knowledge is of utmost importance not only to obtain better results in respective treatments, but also to offer minimal risk to the operator and user when used in biomedical applications.…”

Thermal Characteristics of Helical Coiled Heat Exchanger with Graphene-Deionized Water on Waste Heat Recovery of Combustion Stack Gas

“…To measure the discharge at the electrode, the resistor was replaced by a 3-nF capacitor. The discharge energy per cycle was calculated based on the area of the charge-voltage Lissajous figure (Kostov et al, 2010). The mean power consumption was calculated by multiplying the energy of each cycle by the source frequency (Mahoney et al, 2010).…”