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Choudhury B, Lednicky JA, Loeb JC, Portugal S, Roy S. Inactivation of SARS CoV-2 on porous and nonporous surfaces by compact portable plasma reactor. Front Bioeng Biotechnol 2024; 12:1325336. [PMID: 38486867 PMCID: PMC10937532 DOI: 10.3389/fbioe.2024.1325336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 02/05/2024] [Indexed: 03/17/2024] Open
Abstract
We report the inactivation of SARS CoV-2 and its surrogate-Human coronavirus OC43 (HCoV-OC43), on representative porous (KN95 mask material) and nonporous materials (aluminum and polycarbonate) using a Compact Portable Plasma Reactor (CPPR). The CPPR is a compact (48 cm3), lightweight, portable and scalable device that forms Dielectric Barrier Discharge which generates ozone using surrounding atmosphere as input gas, eliminating the need of source gas tanks. Iterative CPPR exposure time experiments were performed on inoculated material samples in 3 operating volumes. Minimum CPPR exposure times of 5-15 min resulted in 4-5 log reduction of SARS CoV-2 and its surrogate on representative material samples. Ozone concentration and CPPR energy requirements for virus inactivation are documented. Difference in disinfection requirements in porous and non-porous material samples is discussed along with initial scaling studies using the CPPR in 3 operating volumes. The results of this feasibility study, along with existing literature on ozone and CPPR decontamination, show the potential of the CPPR as a powerful technology to reduce fomite transmission of enveloped respiratory virus-induced infectious diseases such as COVID-19. The CPPR can overcome limitations of high temperatures, long exposure times, bulky equipment, and toxic residuals related to conventional decontamination technologies.
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Affiliation(s)
- Bhaswati Choudhury
- SurfPlasma, Inc., Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - John A. Lednicky
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
- Department of Environmental and Global Health, University of Florida, Gainesville, FL, United States
| | - Julia C. Loeb
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
- Department of Environmental and Global Health, University of Florida, Gainesville, FL, United States
| | - Sherlie Portugal
- SurfPlasma, Inc., Gainesville, FL, United States
- School of Electrical Engineering, Technological University of Panama, Panama City, Panama
| | - Subrata Roy
- SurfPlasma, Inc., Gainesville, FL, United States
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, United States
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Kimura S, Ishikawa S, Hayashi N, Fujita K, Inatomi Y, Suzuki S. Bacterial and fungal bioburden reduction on material surfaces using various sterilization techniques suitable for spacecraft decontamination. Front Microbiol 2023; 14:1253436. [PMID: 38152378 PMCID: PMC10751312 DOI: 10.3389/fmicb.2023.1253436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/28/2023] [Indexed: 12/29/2023] Open
Abstract
Planetary protection is a guiding principle aiming to prevent microbial contamination of the solar system by spacecraft (forward contamination) and extraterrestrial contamination of the Earth (backward contamination). Bioburden reduction on spacecraft, including cruise and landing systems, is required to prevent microbial contamination from Earth during space exploration missions. Several sterilization methods are available; however, selecting appropriate methods is essential to eliminate a broad spectrum of microorganisms without damaging spacecraft components during manufacturing and assembly. Here, we compared the effects of different bioburden reduction techniques, including dry heat, UV light, isopropyl alcohol (IPA), hydrogen peroxide (H2O2), vaporized hydrogen peroxide (VHP), and oxygen and argon plasma on microorganisms with different resistance capacities. These microorganisms included Bacillus atrophaeus spores and Aspergillus niger spores, Deinococcus radiodurans, and Brevundimonas diminuta, all important microorganisms for considering planetary protection. Bacillus atrophaeus spores showed the highest resistance to dry heat but could be reliably sterilized (i.e., under detection limit) through extended time or increased temperature. Aspergillus niger spores and D. radiodurans were highly resistant to UV light. Seventy percent of IPA and 7.5% of H2O2 treatments effectively sterilized D. radiodurans and B. diminuta but showed no immediate bactericidal effect against B. atrophaeus spores. IPA immediately sterilized A. niger spores, but H2O2 did not. During VHP treatment under reduced pressure, viable B. atrophaeus spores and A. niger spores were quickly reduced by approximately two log orders. Oxygen plasma sterilized D. radiodurans but did not eliminate B. atrophaeus spores. In contrast, argon plasma sterilized B. atrophaeus but not D. radiodurans. Therefore, dry heat could be used for heat-resistant component bioburden reduction, and VHP or plasma for non-heat-resistant components in bulk bioburden reduction. Furthermore, IPA, H2O2, or UV could be used for additional surface bioburden reduction during assembly and testing. The systemic comparison of sterilization efficiencies under identical experimental conditions in this study provides basic criteria for determining which sterilization techniques should be selected during bioburden reduction for forward planetary protection.
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Affiliation(s)
- Shunta Kimura
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
- Space Exploration Innovation Hub Center, Japan Aerospace Exploration Agency, Sagamihara, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Sagamihara, Japan
| | - Shu Ishikawa
- Engineering Division, Kajima Corporation, Tokyo, Japan
| | - Nobuya Hayashi
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhisa Fujita
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
- Safety and Mission Assurance Department, Japan Aerospace Exploration Agency, Tsukuba, Japan
| | - Yuko Inatomi
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
- Space Exploration Innovation Hub Center, Japan Aerospace Exploration Agency, Sagamihara, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Sagamihara, Japan
| | - Shino Suzuki
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan
- Space Exploration Innovation Hub Center, Japan Aerospace Exploration Agency, Sagamihara, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Sagamihara, Japan
- Geobiology and Astrobiology Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
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T P R, Kar S. Effect of an additional floating electrode on radio frequency cross-field atmospheric pressure plasma jet. Sci Rep 2023; 13:10665. [PMID: 37393352 DOI: 10.1038/s41598-023-37805-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/28/2023] [Indexed: 07/03/2023] Open
Abstract
Atmospheric pressure plasma jets with cross-field electrode configuration are a potential jet design for gases with high breakdown fields. This study focuses on the effect of an additional floating electrode on the cross-field plasma jet properties. Detailed experiments are done with the additional floating electrodes of different widths introduced below the ground electrode in a plasma jet with a cross-field electrode configuration. It is observed that in the presence of an additional floating electrode in the jet propagation path, less applied power is needed for the plasma jet to cross the nozzle and jet length increases. This threshold power, as well as the maximum jet length, depends on the electrode widths. A detailed analysis of charge dynamics in the presence of an additional floating electrode shows decrement in the net charge transferred radially to the external circuit through the ground electrode, and an increment in the net charge transferred axially. Increment in the optical emission intensity of reactive oxygen and nitrogen species, as well as the relative yield of ions like N[Formula: see text], O[Formula: see text], OH[Formula: see text], NO[Formula: see text], O[Formula: see text], and OH[Formula: see text] in the plasma plume, that are crucial for biomedical applications suggest an improvement in the reactivity of plasma plume in the presence of additional floating electrode.
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Affiliation(s)
- Radhika T P
- Department of Energy Science and Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Satyananda Kar
- Department of Energy Science and Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
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Muto R, Hayashi N. Sterilization characteristics of narrow tubing by nitrogen oxides generated in atmospheric pressure air plasma. Sci Rep 2023; 13:6947. [PMID: 37117603 PMCID: PMC10147937 DOI: 10.1038/s41598-023-34243-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 04/26/2023] [Indexed: 04/30/2023] Open
Abstract
The sterilization characteristics of active species generated by an atmospheric dielectric barrier discharge plasma using air and oxygen at the inner surface of silicone tubing were investigated. A dielectric barrier discharge torch plasma device was installed at one end of the tube and generated long-lived active species that flowed into the tube. A strip-type biological indicator with a 105-cell bacterial spore was placed at the opposite end of the 60 cm tube. Sterilization was completed within 30 min by active particles generated from the air plasma. The main factors contributing to the sterilization by air plasma were HNO3 and N2O5. When organic materials (keratin, aspartic acid, and dipicolinic acid) reflecting components of the bacterial spore, were treated by the sterilization procedure there was little effect on dipicolinic acid. Keratin was oxidized by ozone and NOx generated from the oxygen and air plasmas, respectively. Aspartic acid underwent little change in composition from ozone generated from the oxygen plasma, whereas nitro (NO2), nitroso (NO), and aldehyde (CHO) groups were formed from ozone and NOx generated from the air plasma.
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Affiliation(s)
- Reona Muto
- Interdisciplinary Graduate School of Engineering Sciences, Department of Advanced Energy Engineering Science, Kyushu University, Fukuoka, 816-8580, Japan
| | - Nobuya Hayashi
- Interdisciplinary Graduate School of Engineering Sciences, Department of Advanced Energy Engineering Science, Kyushu University, Fukuoka, 816-8580, Japan.
- International Research Center for Space and Planetary Environmental Science, Kyushu University, Fukuoka, 819-0395, Japan.
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