Session TM13: Mini-Conference on Plasma Applications to Ameliorate Covid-19 I

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Pandemic infection due to SARS-CoV2 has spread globally via respiratory droplets and via aerosol. Evidence of viral RNA has also been found in the stool and on environmental surfaces. Young children carry extremely high level of virus in their nose that is likely to contaminate surrounding environment requiring frequent decontamination. In addition, shortage of Personal Protective Equipment (PPE) in resource-constraint settings requires health care workers to wear them for prolonged period with compromised integrity. Need for immediate access to disinfection can obviate the need to wear such PPE. Innovative technology will help surface disinfection in the day care centers, school, hospitals and at home where ill individuals are quarantined. With expertise of physicians, physicists, and biomedical engineers these technologies can be developed and implemented by public health professionals to curtail person-to person transmission of SARS CoV2. These technologies need to be low cost and widely used to reduce disease burden in resource-constraint settings where there is low hygiene. Newer technology using UV light and vaporized hydrogen peroxide has shown to reduce bacterial contamination in hospitals but not in community settings. In order to disinfected hospital rooms or PPE using these technologies, patients/health care workers cannot be in the room. One of the newer technologies like portable of cold plasma in inactivating the SARS-COV2 is being explored for widespread use. Antimicrobial properties of Cold plasma makes its attractive use during the era of SARs-CoV 2 pandemic.   

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It is well known that ultraviolet (UV) is able to damage both the protein capsid and nucleic acid of a virus. Based on that, cold atmospheric plasma (CAP) devices are thus potentially an effective broadband sanitation tool. Responding to the global COVID-19 threat, it is quite urgent to develop CAP devices with the following two features. First, considering the strong absorption of vacuum UV (VUV) of air, the discharge unit in the device has to be close to the target with a safety cover to prevent the side leak of VUV. In this study, we also summarized how UV in the air can generate reactive oxygen and nitrogen species (RONS) with the help of a strong electric field. Therefore, the RONS emission from the device may also deactivate the virus. Second, the device has to be mobile, easy to maneuver, and low-cost. Therefore, we developed several prototypes that are hand-held devices and powered by rechargeable lithium-ion batteries. Considering the shortage of consumables, such as ethanol, these electric-powered sanitation devices can be a good replacement for the liquid sanitation solutions.   

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The diagnosis of SARS Corona virus-2 (SARS-CoV-2) infection and the health management of its associated disease COVID-19 requires the detection of antibody responses. The time pattern of detectability of IgM and IgG antibodies is usually taken as the basis for distinction between acute, recent and past infections. Thereby IgM directed towards viral proteins is regarded as an early marker of infection, which is lost after a few weeks. IgG directed towards viral proteins is expected to become detectable after the IgM response and to be maintained for a much longer time. The analysis of the so far available data on antibody responses towards SARS CoV-2 shows a high degree of variability of the pattern of IgM/IgG detectability in serum. This may easily lead to confusion and diagnostic misinterpretations. This talk presents immunological mechanisms that explain the observed variability of the antibody responses. In addition, a path for the resolution of these diagnostic problems is suggested. Its technical application is based on our knowledge about the maturation of the binding strength of IgG antibodies (termed ``avidity'') after an infection. The use of this method for health management of COVID-19 and for the control of vaccination programs will be discussed.   

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The COVID-19 pandemic has brought to the forefront the need for effective disinfection and treatment for personal, medical, and public preparedness for biological emergencies. Low power (\textasciitilde 1 W) low temperature plasma (LTP) devices that can provide personal and possibly public protection against current and future infections due to their bio active properties (such as reactive radical and non-radical atomic and molecular species, electrons, currents, electric fields, UV, etc.). A surface dielectric barrier discharge (DBD) using a flexible printed circuit design operates in ambient air without any additional gas flow and power density of \textless 0.5 W/cm$^{\mathrm{2}}$. Using E-coli, we demonstrate a 4log$_{\mathrm{10}}$ reduction of the bacterial load on a glass surface in direct contact with the device. An added dramatic improvement of surface disinfection results from a combined action of plasma and a common disinfectant. We discuss the efficacy of other DBD devices operating without a gas flow in ambient air. This research was performed at the Princeton Collaborative Low Temperature Plasma Research Facility (PCRF) at PPPL, and supported by the US DOE under contract DE-AC02-09CH11466.   

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It is known by now that on inanimate surfaces, infectious SARS-CoV2 virions can be detected for up to 3 days which poses challenges for limiting transmission [1]. While heat and chemicals have proven to be effective for inactivating viruses such as SARS-CoV2, those methods cannot be readily applied to all surfaces/materials which may be heat labile. Furthermore, chemical disinfectants can be harmful. To address this challenge and because of the urgency of the situation with the COVID-19 pandemic, we tested the efficacy of commercially available home-use plasma devices for the rapid and inexpensive antiviral treatment of surfaces. These devices include d'Arsonval high frequency current source [2] and plasma globe [3]. Both devices use a dielectric-barrier discharge for the plasma generation. They are already readily available for public purchase through on-line markets, and easy to use. Results of experimental characterization and antiviral tests for both devices will be presented in this talk. [1] N. van Doremalen et al., New England J. Med. 382, 1564 (2020) [2] J. Napp et al., GMS Hygiene and Infection Control 10 (2015) [3] M. Burin et al., Phys. Plasmas 22, 053509 (2015).   

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SARS-CoV-2 appears to be primarily transmitted via droplets of different sizes causing COVID-19. We report on recently commenced studies of SARS-CoV-2 in droplets where we use high power, short laser pulses to induce fragmentation and ionization of virus-laden droplets, combined with betatron x-ray imaging. Our goal is to collect ion spectra and to correlate them with images to reconstruct the microenvironment of their origin for a series of droplet compositions. If we are successful in detecting fingerprint ions then this can be used as a diagnostic tool for rapid identification of SARS-CoV-2 in biological specimen, including saliva, nasopharyngeal swabs and tracheal aspirates. In addition, this approach can identify biochemical targets to decrease viral viability by modifying the microenvironment of SARS-CoV-2-laden droplets limiting the spread of COVID-19.   

Plasma Wand Source for Surface Disinfection

Presented here are results from an atmospheric pressure plasma-to-surface applicator for contactless rapid surface disinfection that can be applied to both hard and soft surfaces, without damage the surface. The technology is envisioned for use in those areas frequented by the public or those areas that are used by many over the course of a day, and which are generally difficult to disinfect with quick turnover time. The source produces reactive oxygen species using a room temperature plasma that removes biological contaminants from the surfaces regardless of surface morphology. Discharge power consumption and reactive species production is accessed using diagnostics and a global model. Additionally, plasma driven surface reaction mechanisms are discussed.   

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In this talk attention is drawn to the importance of accounting for osmotic pressure when analyzing physiological effects on cells and viruses in plasma medicine and disinfection. The effect of a plasma on living cells and viruses in a physiological solution can be related to a change in pH and the osmotic pressure difference across the cell membrane, as a result of the injection into a physiological solution of additional long-lived solvated (hydrated) ions by the plasma. This, in turn, leads to a stretching or compression of the membrane, depending on the difference of total external and internal pressures. The hypertonic solution mode is most likely realized. The selective effect of plasma on cells, observed in experiments, may be associated with the change in the mechanical properties of membranes (and thereby, a weakening of their protective properties). Corresponding estimates are given. Our work does not claim to have found the only reason, why weakly ionized non-equilibrium plasma leads to cell and virus death, but has identified a potential further physical mechanism that has relevance in plasma induced biological effects. 1. M. N. Shneider, M. Pekker, J. Appl. Phys. 123, 204701 (2018); 2. M.N. Shneider, M. Pekker, Plasma Res. Express 1, 045001 (2019)