Atmospheric-pressure, nonthermal plasma sterilization of microorganisms in liquids and on surfaces (original) (raw)
Related papers
Air and Water Sterilization using Non-Thermal Plasma
2007 IEEE Pulsed Power Plasma Science Conference, 2007
The sterilization effect of plasma on air and water were investigated in this study * . For air sterilization, a small scale model of HVAC was designed and Dielectric Barrier Discharge plasma source was used for treatment of air. This PDRF (Pathogen Detection and Remediation Facility) consisted of a circulatory airflow system, a plasma chamber and a sampling system. Air sterilization experiments were performed and the inactivation of Escherichia coli was studied. Conventional water sterilization methods such as chlorination, ozonation, filtration, UV irradiation etc have several drawbacks. Pulsed plasma discharge for the destruction of microorganisms in waste water and potable water is a cost effective technique developed recently. The energy efficiency of different types of plasma discharges in water contaminated with Escherichia coli has been studied. The effect of initial concentration of bacterial solution on the inactivation efficiency has also been studied 1-4244-0914-4/07/$25.00 ©2007 IEEE.
Applied Biochemistry and Biotechnology, 2010
We developed and employed a new geometrical structure of dielectric barrier discharge in atmospheric pressure for bacterial broad spectrum sterilization. We utilized a plasma source having an AC power supply at 50 HZ and 5,400 V (rms value). We prepared suspensions of the Gram-negative bacteria species (Escherichia coli, Pseudomonas aeruginosa) and a Gram-positive of Bacillus cereus with Luria-Bertani broth media up to OD 600 nm =0.25 of McFarland standard. Afterglow of non-thermal atmospheric pressure plasma treated these suspensions. The influence of the atmospheric plasma afterglow on the species was assayed in different time durations 5, 10, and 15 min. The spectroscopic results of this investigation indicated that the survival reduction of the species can reach to 100% for P. aeruginosa in an exposure time of 10 min, E. coli and B. cereus in an exposure time of 15 min.
International journal of …, 2001
Utilizing an ionized gas (plasma) to achieve sterilization is an alternative to conventional sterilization means as far as sterilization of heat-sensitive materials and innocuity of sterilizing agents are concerned. The literature on plasma sterilization is reviewed. A major issue of plasma sterilization is the respective roles of UV photons and reactive species such as atomic and radicals. Insight into this matter is obtained by analyzing the survival curves of microorganisms. In contrast to classical sterilization where such plots show a unique straight line, plasma sterilization yields survival diagrams with two or three different linear segments. Three basic mechanisms are involved in the plasma inactivation of microorganisms: (A) direct destruction by UV irradiation of the genetic material of microorganisms; (B) erosion of the microorganisms atom by atom, through intrinsic photodesorption by UV irradiation to form volatile compounds combining atoms intrinsic to the microorganisms; (C) erosion of the microorganisms, atom by atom, through etching to form volatile compounds as a result of slow combustion using oxygen atoms or radicals emanating from the plasma. In some cases, etching is further activated by UV photons, increasing the elimination rate of microorganisms. These mechanisms make plasma sterilization totally different from classical sterilization techniques and suggest its use to inactivate nonconventional infectious agents such as the abnormal prions.
Comparison of Direct and Indirect Effects of Non-Thermal Atmospheric-Pressure Plasma on Bacteria
Plasma Processes and Polymers, 2007
Effectiveness of non-thermal atmospheric pressure Floating Electrode Dielectric Barrier Discharge plasma in interaction with living organisms is investigated. Two regimes are analyzed: where this plasma comes in direct contact with the organism and where this plasma in separated for the treatment target by a grounded mesh. Direct plasma contact is found to be more efficient at sterilization and the mechanism is hypothesized to be due to charged species delivered by plasma to the surface of the organism.
Plasma for air and water sterilization
2008
This chapter describes the research efforts of Drexel Plasma Institute (DPl) in the area of plasma-based air and water sterilization. Motivation of this research is presented as well as the methods for selection of parameters for the experimental systems. Experimentally obtained results for air sterilization demonstrate that the direct influence of plasma charged particles on airborne bacteria in combination with active chemical substances generated by plasma is the probable reason for high sterilization efficiency of the Dielectric Barrier Grating Discharge (DBGD). Energy input on the level of 13 kJ/m3 is enough to reach a 5-log reduction of viable E. coli bacteria. Experimentally reached D-value (the dosage required for a 90Yo reduction of the number of viable microorganisms) for E. coli bacteria deactivation in water using spark discharge is very low, about 125 kJlm3, and UV-radiation is the most plausible sterilization factor in this case. A new seminumerical model is proposed for initial phase of electrical breakdown in water.
Low temperature atmospheric plasma for microbial decontamination
2013
Low temperature Plasma (LTP) is a high-energy gas that is created when an electrical current is passed through a gas. Until recently, plasmas could only be created at relatively high temperatures in a vacuum and the use of plasma on sensitive materials such as human tissue, food products, medical devices and the packaging industry, was therefore impractical. However, over the last few years technological breakthroughs have made it possible to produce low temperature plasmas under atmospheric conditions providing many advantages. Plasma discharges with a higher oxygen concentration have been associated with increased levels of microbial survival inhibition due to oxygen based active species, atomic oxygen and ozone. Low temperature plasmas have shown success in decontamination of a wide range of microorganisms including bacteria, fungi and algae and has even shown success in damaging bacterial spores. These factors have brought this exciting new, emerging technology to the forefront ...
AIP Advances, 2020
In this work, the bacteria inactivation using the nonthermal atmospheric pressure plasma has been studied. The bacteria inactivation was conducted using a self-design nonthermal atmospheric pressure plasma jet system. During this experiment, Escherichia coli was used as an objective microorganism. The primary operating gas for the plasma jet used in this work is helium, and small fractions of oxygen or nitrogen (0.2%) were used as the secondary gas. The three plasma jet cases were operated at 3.5 kV, 14 l/m, and 7 mm, which represented the applied voltage, gas flow rate, and distance from the nozzle, respectively. The types of reactive species have been examined using optical emission spectroscopy. The gas temperature and optical emission spectrum were measured under the same condition. The active species of OH, OII, OI, N21+, N22+, and He are indented in the UV-vis wavelength range. The inactivation of E. coli bacteria has occurred after 20 s of nonthermal plasma treatment, whether...
Design an Atmospheric Pressure Non-Thermal Plasma Device for Killing Bacteria
Abstract In this work, a dielectric barrier discharge DBD plasma system has been designed and fabricated . This system produces non-thermal atmospheric pressure plasma , where two planar stainless steel electrodes with a diameter (4.5cm ) were used . Besides an upper electrode was covered by a sheet of Pyrex with thickness (1.2 mm) as an electrical insulator . For comparison purpose, another electrode with a diameter (2.5cm) was used as an upper electrode . The distance between the electrodes was fixed at two values: 1mm and 2mm . Characteristics of the system such as I-V curve and breakdown voltage at many different conditions were studied . The study also included the effect of both area of electrodes and the distance between the electrodes on the current of the system and breakdown voltage, It was found that by increasing the distance between the electrodes the breakdown voltage increased. It was also found that the current values increases on the decrease in the distance between the electrodes . Also it was found that by increasing the area of electrode the value of breakdown voltage increases and the current value decreases . This work also included the application of the plasma produced from the system in the field of bacterial sterilization , where samples of Gram- positive bacteria (Staphylococcus aureus) and Gram- negative bacteria (Escherichia coli) were exposed to intervals (1-20)second . It was found that the percentage of the killing of Gram- positive bacteria (S. aureas) was 100% at time (14)second , whereas ,the percentage of the killing of Gram-negative bacteria (E.coli) was 100% at (10) second. This shows that Gram-positive bacteria is more resistant than Gram-negative bacteria to sterilization by DBD plasma system.
Non-thermal plasma applications in air sterilization
The 31st IEEE International Conference on Plasma Science, 2004. ICOPS 2004. IEEE Conference Record - Abstracts., 2004
In our present study, two non-thermal plasma devices, dielectric barrier discharge and magnetically-rotated gliding arc, are being used to sterilize air containing high concentrations of viral and bacterial bioaerosols. A Pathogen Detection and Remediation Facility was designed for bioaerosol generation, containment, and sampling during plasma sterilization experiments.
Inactivation of Bacteria in Flight by Direct Exposure to Nonthermal Plasma
IEEE Transactions on Plasma Science, 2000
Plasma treatment is a promising technology for fast and effective sterilization of surfaces, waterflow, and airflow. The treatment of airflow is an important area of healthcare and biodefense that has recently gained the interest of many scientists. In this paper, we describe a dielectric barrier grating discharge (DBGD) which is used to study the inactivation of airborne Escherichia coli inside a closed air circulation system. Earlier published results indicate approximately 5-log reduction (99.999%) in the concentration of the airborne bacteria after single DBGD exposure of 10-s duration. This paper investigates plasma species influencing the inactivation. The two major factors that are studied are the effect of charged and short-lived species (direct exposure to plasma) and the effect of ozone. It is shown that for a 25% reduction in direct exposure, the inactivation falls from 97% to 29% in a single pass through the grating. The influence of ozone was studied by producing ozone remotely with an ozone generator and injecting the same concentration into the system, as that produced by the DBGD plasma. The results show a 10% reduction in the bacterial load after 10-s exposure to ozone; thus, ozone alone may not be one of the major inactivating factors in the plasma.