Viricidal Activity of Thermoplastic Polyurethane Materials with Silver Nanoparticles.

The use of diverse Ag-based nanoparticulated forms has shown promising results in controlling viral propagation. In this study, a commercial nanomaterial consisting of ceramic-coated silver nanoparticles (AgNPs) was incorporated into thermoplastic polyurethane (TPU) plates using an industrial protocol, and the surface composition, ion-release dynamics and viricidal properties were studied. The surface characterization by FESEM-EDX revealed that the molar composition of the ceramic material was 5.5 P:3.3 Mg:Al and facilitated the identification of the embedded AgNPs (54.4 ± 24.9 nm). As determined by ICPMS, the release rates from the AgNP-TPU into aqueous solvents were 4 ppm/h for Ag and Al, and 28.4 ppm/h for Mg ions. Regarding the biological assays, the AgNP-TPU material did not induce significant cytotoxicity in the cell lines employed. Its viricidal activity was characterized, based on ISO 21702:2019, using the Spring viraemia of carp virus (SVCV), and then tested against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The results demonstrated that AgNP-TPU materials exhibited significant (75%) and direct antiviral activity against SVCV virions in a time- and temperature-dependent manner. Similar inhibition levels were found against SARS-CoV-2. These findings show the potential of AgNP-TPU-based materials as a supporting strategy to control viral spread.

Characterization of Planktochlorella nurekis Extracts and Virucidal Activity against a Coronavirus Model, the Murine Coronavirus 3.

Certain members of the Coronaviridae family have emerged as zoonotic agents and have recently caused severe respiratory diseases in humans and animals, such as SARS, MERS, and, more recently, COVID-19. Antivirals (drugs and antiseptics) capable of controlling viruses at the site of infection are scarce. Microalgae from the Chlorellaceae family are sources of bioactive compounds with antioxidant, antiviral, and antitumor activity. In the present study, we aimed to evaluate various extracts from Planktochlorella nurekis in vitro against murine coronavirus-3 (MHV-3), which is an essential human coronavirus surrogate for laboratory assays. Methanol, hexane, and dichloromethane extracts of P. nurekis were tested in cells infected with MHV-3, and characterized by UV-vis spectrophotometry, nuclear magnetic resonance (NMR) spectroscopy, ultraperformance liquid chromatography-mass spectrometry (UPLC-MS), and the application of chemometrics through principal component analysis (PCA). All the extracts were highly efficient against MHV-3 (more than a 6 Log unit reduction), regardless of the solvent used or the concentration of the extract, but the dichloromethane extract was the most effective. Chemical characterization by spectrophotometry and NMR, with the aid of statistical analysis, showed that polyphenols, carbohydrates, and isoprene derivatives, such as terpenes and carotenoids have a more significant impact on the virucidal potential. Compounds identified by UPLC-MS were mainly lipids and only found in the dichloromethane extract. These results open new biotechnological possibilities to explore the biomass of P. nurekis; it is a natural extract and shows low cytotoxicity and an excellent antiviral effect, with low production costs, highlighting a promising potential for development and implementation of therapies against coronaviruses, such as SARS-CoV-2.

Efficacy of Ultraviolet-C Devices for the Disinfection of Personal Protective Equipment Fabrics and N95 Respirators.

Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, a plethora of ultraviolet-C (UV-C) disinfection products have come to market, especially in emerging economies. UV-C-based disinfection products for mobile phones, food packaging, face masks and personal protective equipment (PPE), and other everyday objects are available in popular electronic-commerce platforms as consumer products. Product designers from multinational to startup companies began to design UV-C disinfection products but had no prior-art reference, user feedback, or validation of product efficacy, which are important stages in product design. A UV-C disinfection product cannot be assessed by most consumers for its viricidal efficacy. Many firms entered the domain of UV-C products and were unaware of the necessary validation requirements. Lack of availability and access to virology laboratories, due to lockdowns in countries, and lack of standards and certification for UV-C disinfection products limited product designers and firms in benchmarking their UV-C-based devices before market release. This work evaluates two UV-C disinfection devices for viricidal efficacy on PPE fabric and National Institute for Occupational Safety and Health (NIOSH)-certified N95 respirators through controlled experiments using the H1N1 virus, which is enveloped and is transmitted via the respiratory route similar to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of COVID-19. The experiment also evaluated the effectiveness of chemical disinfectants along with and versus UV-C disinfection. Experiments for material selection, UV dose calculation, and UV endurance of PPE samples to be disinfected are also discussed. The outcome of this work establishes a systematic method to validate the efficacy of UV-C disinfection products. The design guidelines would benefit product designers in designing UV-C-based disinfection products.

On the emergence of antibacterial and antiviral copper cold spray coatings.

In this literature review, the antipathogenic properties and contact-mediated antibacterial and antiviral performance of copper cold spray surfaces are assessed and compared with alternative antimicrobial materials that are able to kill and/or inactivate infectious agents via direct contact. Discussion is also provided concerning the suitability of copper cold spray material consolidations as biocidal and viricidal surfaces that retain long-term functionality as a preventative measure against fomite transmission of pathogenic agents and hospital-acquired infections from contaminated high-touch surfaces. Numerable alternative antimicrobial coatings and surfaces that do not rely upon the oligodynamic action of copper are detailed. Given the ongoing need for recognition of said alternative antimicrobial materials by authoritative agencies, such as the U.S. Environmental Protection Agency, the relevant literature on non-copper-based antipathogenic coatings and surfaces are then described. Furthermore, a wide-ranging take on antipathogenic copper cold spray coatings are provided and consideration is given to the distinctive grain-boundary mediated copper ion diffusion pathways found in optimizable, highly deformed, copper cold spray material consolidations that enable pathogen inactivation on surfaces from direct contact. To conclude this literature review, analysis of how copper cold spray coatings can be employed as a preventative measure against COVID-19 was also presented in light of on-going debates surrounding SARS-CoV-2's non-primary, but non-negligible, secondary transmission pathway, and also presented in conjunction with the inevitability that future pathogens, which will be responsible for forthcoming global pandemics, may spread even more readily via fomite pathways too.

Cupric Oxide Coating That Rapidly Reduces Infection by SARS-CoV-2 via Solids.

The ongoing COVID-19 pandemic has created a need for coatings that reduce infection from SARS-CoV-2 via surfaces. Such a coating could be used on common touch surfaces (e.g., door handles and railings) to reduce both disease transmission and fear of touching objects. Herein, we describe the design, fabrication, and testing of a cupric oxide anti-SARS-CoV-2 coating. Rapid loss of infectivity is an important design criterion, so a porous hydrophilic coating was created to allow rapid infiltration of aqueous solutions into the coating where diffusion distances to the cupric oxide surface are short and the surface area is large. The coating was deposited onto glass from a dispersion of cuprous oxide in ethanol and then thermally treated at 700 °C for 2 h to produce a CuO coating that is ≈30 µm thick. The heat treatment oxidized the cuprous oxide to cupric oxide and sintered the particles into a robust film. The SARS-CoV-2 infectivity from the CuO film was reduced by 99.8% in 30 min and 99.9% in 1 h compared to that from glass. The coating remained hydrophilic for at least 5 months, and there was no significant change in the cross-hatch test of robustness after exposure to 70% ethanol or 3 wt % bleach.

Viricidal treatments for prevention of coronavirus infection.

Coronavirus disease 2019 (COVID-19), which causes severe acute respiratory syndrome and lung failure, is caused by the novel coronavirus, also known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Due to high transmission rates from individual to individual, it has progressed to a pandemic. However, indirect transmission from inanimate objects or surfaces that have come in contact with a patient poses an even more significant threat as it is difficult to trace the source of infection in these cases. Therefore, these surfaces and objects require disinfection with chemicals having potent viricidal activity. These include alcohols, aldehydes, quaternary ammonium compounds, chlorhexidine, and chlorine-based disinfectants, among others. They vary in their viricidal activity depending on their structure, concentrations, and mechanism of action. Several studies have looked into these agents and the transmission of the virus related to it. Moreover, certain viricides, if used as constituents of commercially available oral disinfectants, can further aid in preventing ventilator-associated pneumonia and maintain oral hygiene. However, these chemicals are not entirely free of potential hazards. In this review, we have compiled and critically appraised some commonly used viricidal agents in healthcare settings and the role they can play in the prevention of SARS-CoV-2 transmission.

Sars-CoV-2 (COVID-19) inactivation capability of copper-coated touch surface fabricated by cold-spray technology.

In this work, cold-spray technique was employed for rapid coating of copper on in-use steel parts. The primary intention was to alleviate the tendency of SARS-CoV-2 (COVID-19) virus to linger longer on touch surfaces that attract high-to-medium volume human contact, such as the push plates used in publicly accessed buildings and hospitals. The viricidal activity test revealed that 96% of the virus was inactivated within 2-hrs, which was substantially shorter than the time required for stainless steel to inactivate the virus to the same level. Moreover, it was found that the copper-coated samples significantly reduces the lifetime of COVID-19 virus to less than 5-hrs. The capability of the cold-spray technique to generate antiviral copper coating on the existing touch surface eliminates the need for replacing the entire touch surface application with copper material. Furthermore, with a short manufacturing time to produce coatings, the re-deployment of copper-coated parts can be accomplished in minutes, thereby resulting in significant cost savings. This work showcases the capability of cold-spray as a potential copper-coating solution for different in-use parts and components that can act as sources for the spread of the virus.