Structural and Immunoreactivity Properties of the SARS-CoV-2 Spike Protein upon the Development of an Inactivated Vaccine.

Inactivated vaccines are promising tools for tackling the COVID-19 pandemic. We applied several protocols for SARS-CoV-2 inactivation (by ß-propiolactone, formaldehyde, and UV radiation) and examined the morphology of viral spikes, protein composition of the preparations, and their immunoreactivity in ELISA using two panels of sera collected from convalescents and people vaccinated by Sputnik V. Transmission electron microscopy (TEM) allowed us to distinguish wider flail-like spikes (supposedly the S-protein's pre-fusion conformation) from narrower needle-like ones (the post-fusion state). While the flails were present in all preparations studied, the needles were highly abundant in the ß-propiolactone-inactivated samples only. Structural proteins S, N, and M of SARS-CoV-2 were detected via mass spectrometry. Formaldehyde and UV-inactivated samples demonstrated the highest affinity/immunoreactivity against the convalescent sera, while ß-propiolactone (1:2000, 36 h) and UV-inactivated ones were more active against the sera of people vaccinated with Sputnik V. A higher concentration of ß-propiolactone (1:1000, 2 h) led to a loss of antigenic affinity for both serum panels. Thus, although we did not analyze native SARS-CoV-2 for biosafety reasons, our comparative approach helped to exclude some destructive inactivation conditions and select suitable variants for future animal research. We believe that TEM is a valuable tool for inactivated COVID-19 vaccine quality control during the downstream manufacturing process.

Resolving the "health vs environment" dilemma with sustainable disinfection during the COVID-19 pandemic.

The overuse of disinfection during the COVID-19 pandemic leads to an emerging "health versus environment" dilemma that humans have to face. Irresponsible and unnecessary disinfection should be avoided, while comprehensive evaluation of the health and environmental impacts of different disinfectants is urgently needed. From this discussion, we reach a tentative conclusion that hydrogen peroxide is a green disinfectant. Its on-demand production enables a circular economy model to solve the storage issues. Water, oxygen, and electrons are the only feedstock to generate H2O2. Upon completion of disinfection, H2O2 is rapidly converted back into water and oxygen. This model adopts several principles of green chemistry to ensure overall sustainability along the three stages of its whole life cycle, i.e., production, disinfection, and decomposition. Physical methods, particularly UV irradiation, also provide sustainable disinfection with minimal health and environmental impacts.

The Effect of Disinfectants on the SARS-CoV-2 RNA Detection in Swabs from Various Surfaces.

The COVID-19 pandemic has spread rapidly around the world; some countries have introduced controls on imported products, including testing for viral nucleic acids. In this work, the influence of disinfectants for treating various SARS-CoV-2-contaminated surfaces on the detection of viral RNA fragments in swabs from these surfaces was analyzed using quantitative RT-PCR. Quaternary ammonium salt, hydrogen peroxide, 1-propanol, and sodium salt of dichloroisocyanuric acid, as well as ultraviolet irradiation, were tested as such disinfecting agents. Our results show that without exposure to disinfectants, viral RNA can be detected on the surface of all examined materials for at least 3 days. UV irradiation or irrigation with a disinfectant containing 0.2% active chlorine had the greatest effect on the decontamination of nonporous surfaces as measured by RT-PCR of swabs from these surfaces. Irrigation with disinfectants of porous surfaces (cardboard) had practically no effect on the detection of SARS-CoV-2 RNA by RT-PCR.

A comprehensive review of various approaches for treatment of tertiary wastewater with emerging contaminants: what do we know?

In the last few decades, environmental contaminants (ECs) have been introduced into the environment at an alarming rate. There is a risk to human health and aquatic ecosystems from trace levels of emerging contaminants, including hospital wastewater (HPWW), cosmetics, personal care products, endocrine system disruptors, and their transformation products. Despite the fact that these pollutants have been introduced or detected relatively recently, information about their characteristics, actions, and impacts is limited, as are the technologies to eliminate them efficiently. A wastewater recycling system is capable of providing irrigation water for crops and municipal sewage treatment, so removing ECs before wastewater reuse is essential. Water treatment processes containing advanced ions of biotic origin and ECs of biotic origin are highly recommended for contaminants. This study introduces the fundamentals of the treatment of tertiary wastewater, including membranes, filtration, UV (ultraviolet) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Next, a detailed description of recent developments and innovations in each component of the emerging contaminant removal process is provided.

Antiseptic drugs and disinfectants with experience of the second year of COVID-19 pandemic-related side effects

This review covers publications during the period January 2021 to December 2021 on adverse reactions to antiseptic drugs and disinfectants. Specific agents discussed are alcohols (ethanol, isopropanol), aldehydes (formaldehyde), ethylene oxide, guanidines (chlorhexidine, polyhexamethylene guanidine, and polyhexamethylene biguanidine), benzalkonium compounds, triclosan, povidone-iodine, and sodium hypochlorite. No new data were identified for glutaraldehyde, cetrimide, tosylchloramide, triclocarban, and phenolic compounds. The use of antiseptic drugs and disinfectants has increased considerably since 2020 in various medical and occupational settings, in commerce and gastronomy, as well as in the home, due to their antiviral properties against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the still ongoing Coronavirus Disease 2019 (COVID-19) pandemic. Irritant effects on the respiratory system, the skin and eyes were the most common adverse reaction, while the widespread and occasionally excessive use led to increased reports of poisonings as well as of oral misuse of disinfectants, sometimes associated with serious outcomes such as death from methanol intoxication. Eye exposures in children caused by inadvertent exposures due to unsupervised dispensers in public spaces were pointed out as being specifically problematic. Side effects in the eye may also occur in the general population by improper and unprotected use of UV lamps. The need to improve the safe use of disinfectant devices was pointed out in general.

Fate of Microplastics Released by Discarded Disposable Masks

The pandemic of COVID-19 has led to a surge increase in the production of masks. Due to the rapid propagation of COVID-19 and the long survival time of plastic surfaces, a large number of masks are discharged into the environment without treatment. In this paper, the release of microplastics (MPs) in nature was simulated by using mask samples irradiated by ultraviolet (UV) light. After 28 days of ultraviolet radiation, part of the main chain of the mask was broken and a large number of transparent MPs fell off. The longer the UV irradiation time, the larger the proportion of small particle MPs. The middle layer of surgical mask is the most difficult to release MPs due to charge treatment, and N95 mask is the most difficult to degrade the inner material. © 2022, HARD Publishing Company. All rights reserved.

Antimicrobial Activity of a Titanium Dioxide Additivated Thermoset

The transmission of pathogens via surfaces poses a major health problem, particularly in hospital environments. Antimicrobial surfaces can interrupt the path of spread, while photocatalytically active titanium dioxide (TiO2) nanoparticles have emerged as an additive for creating antimicrobial materials. Irradiation of such particles with ultraviolet (UV) light leads to the formation of reactive oxygen species that can inactivate bacteria. The aim of this research was to incorporate TiO2 nanoparticles into a cellulose-reinforced melamine-formaldehyde resin (MF) to obtain a photocatalytic antimicrobial thermoset, to be used, for example, for device enclosures or tableware. To this end, composites of MF with 5, 10, 15, and 20 wt% TiO2 were produced by ultrasonication and hot pressing. The incorporation of TiO2 resulted in a small decrease in tensile strength and little to no decrease in Shore D hardness, but a statistically significant decrease in the water contact angle. After 48 h of UV irradiation, a statistically significant decrease in tensile strength for samples with 0 and 10 wt% TiO2 was measured but with no statistically significant differences in Shore D hardness, although a statistically significant increase in surface hydrophilicity was measured. Accelerated methylene blue (MB) degradation was measured during a further 2.5 h of UV irradiation and MB concentrations of 12% or less could be achieved. Samples containing 0, 10, and 20 wt% TiO2 were investigated for long-term UV stability and antimicrobial activity. Fourier-transform infrared spectroscopy revealed no changes in the chemical structure of the polymer, due to the incorporation of TiO2, but changes were detected after 500 h of irradiation, indicating material degradation. Specimens pre-irradiated with UV for 48 h showed a total reduction in Escherichia coli when exposed to UV irradiation.

A Critical Review on Diverse Technologies for Advanced Wastewater Treatment During SARS-CoV-2 Pandemic: What Do We Know?

Advanced wastewater treatment technologies are effective methods and currently attract growing attention, especially in arid and semi-arid areas, for reusing water, reducing water pollution, and explicitly declining, inactivating, or removing SARS-CoV-2. Overall, removing organic matter and micropollutants prior to wastewater reuse is critical, considering that water reclamation can help provide a crop irrigation system and domestic purified water. Advanced wastewater treatment processes are highly recommended for contaminants such as monovalent ions from an abiotic source and SARS-CoV-2 from an abiotic source. This work introduces the fundamental knowledge of various methods in advanced water treatment, including membranes, filtration, Ultraviolet (UV) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Following that, an analysis of each process for organic matter removal and mitigation or prevention of SARS-CoV-2 contamination is discussed. Next, a comprehensive overview of recent advances and breakthroughs is provided for each technology. Finally, the advantages and disadvantages of each method are discussed.

Evaluation of the Degradation of Materials by Exposure to germicide UV-C Light through Colorimetry, Tensile Strength and Surface Microstructure Analyses

Due to the COVID19 pandemic, solutions to automate disinfection using UV-C combined with mobile robots are beginning to be explored. It has been proved that the use of these systems highly reduces the risk of contagion. However, its use in real applications is not being as rapid as it needs to be. One of the main market input barriers is the fear of degrading facilities. For this reason, it is crucial to perform a detailed study on the degradation effect of UV-C light on inert materials. This experimental study proves that, considering exposition times equivalent to several work years in hospital rooms, only the appearance of the material is affected, but not their mechanical functionalities. This relevant result could contribute to accelerate the deployment of these beneficial disinfection technologies. For that purpose, a colorimetry test, tensile strength test, and analysis of the surface microstructure were carried out. The results showed that polymers tend to turn yellow, while fabrics lose intensity depending on the color. Red is hardly affected by UV-C, but blue and green are. Thus, this study contributes to the identification of the best materials and colors to be used in rooms subjected to disinfection processes. In addition, it is shown how the surface microstructure of the materials is altered in most of the materials, but not the tensile strength of the fabrics.

Amphiphilic Janus Microspheres Prepared by Caged Photoactivatable Alkoxysilane

A simple photolysis route was proposed to prepare Amphiphilic Janus Particles (AJP) based on SiO2 microspheres. The surface of SiO2 microspheres were modified by photoactive alkoxysilane, which was synthesized by dealcoholization condensation of 6-nitroveratroyloxycarbonyl and isocyanatopropyl-triethoxysilane. UV irradiation caused eater-breaking allowed for the precise control of hydrophilic modification of the hemispherical exposed particles surfaces. The component and morphology of the obtained particles were characterized by fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy, and the Janus feature was evaluated by scanning electron microscopy, transmission electron microscopy, and dispersity in the oil–water dual-phases. The following results were obtained. The AJP with 450 nm size processes the hydrophilic amino groups on one side and the hydrophobic 6-nitroveratryloxycarbonyl moieties on the other. Additionally, the AJP were located at the phase boundary between water and n-hexane, and the negative charged gold nanoparticles with 25 nm size were adsorbed only onto the side with the positive charged amino groups. The AJP have interfacial adsorption energies that can be as much as three times larger than that of homogeneous particles and thus exhibit excellent surface activities.

An IoT Approach for Monitoring UV Disinfection Robots

The use of ultraviolet germicidal irradiation (UVGI) technology as a means of disinfecting hospitals and other frontline settings has increased significantly in the wake of the COVID-19 pandemic. Although the science of UVGI is well established, it can be difficult to determine in practice if sufficient levels of UVC has been irradiated to kill the target microbes in a room. This research presents the development of a low-cost wireless UVC sensor that can be used to systematically track the UV irradiation dose on target surfaces during a UV disinfection procedure. We present key elements of the design of this device, which included a custom PCB, enclosure, operating software, and graphical user interface. The applicability of the system was assessed through an experiment where the devices were placed at 12 locations in a CT scan treatment room that was subject to a UVGI disinfection procedure using an autonomous UV robot. Over the course of three cleaning sessions, each lasting approximately 10 minutes, it was found that each site location received an average UVC dose of 13mJ/cm2, which is more than published D90 values for SARS-Cov-2, influenza, and a number of known pathogens that are commonly found in hospital settings. This study provides early validation of the potential effectiveness of low-power wireless UV level monitoring technology, which may form part of future distributed room sensing networks or as part of smart wearable devices carried by relevant hospital staff. © 2021 IEEE.

Prediction of Photolysis Kinetics of Viral Genomes under UV254 Irradiation to Estimate Virus Infectivity Loss.

UV254 irradiation disinfection is a commonly used method to inactivate pathogenic viruses in water and wastewater treatment. Model prediction method can serve as a pre-screening tool to quickly estimate the effectiveness of UV254 irradiation on emerging or unculturable viruses. In this study, an improved prediction model was applied to estimate UV254 photolysis kinetics of viral genomes (kpred, genome) based on the genome sequences and their photoreactivity and to correlate with the experimental virus infectivity loss kinetics (kexp, infectivity). The UV254 inactivation data of 102 viruses (including 2 dsRNA, 65 ssRNA, 33 dsDNA and 2 ssDNA viruses) were collected from the published experimental data with kexp, infectivity ranging from 0.016 to 3.49 cm2 mJ-1. The model had fairly good performance in predicting the virus susceptibility to UV254 irradiation except dsRNA viruses (Pearson's correlation coefficient = 0.64) and 70% of kpred, genome fell in the range of 1/2 to 2 times of kexp, infectivity. The positive deviation of the model often occurred for photoresistant viruses with low kexp, infectivity less than 0.20 cm2 mJ-1 (e.g., Adenovirus, Papovaviridae and Retroviridae). We also applied this model to predict the UV254 inactivation rate of SARS-CoV-2 (kpred, genome = 3.168 cm2 mJ-1) and a UV dose of 3 mJ cm-2 seemed to be able to achieve a 2-log removal by conservative calculation using 1/2kpred, genome value. This prediction method can be used as a prescreening tool to assess the effectiveness of UV254 irradiation for emerging/unculturable viruses in water or wastewater treatment.

Reprocessing of N95 masks: Experience from a resource-limited setting in India.

OBJECTIVES: Due to the surge in demand for N95 masks during the Covid-19 pandemic, and considering the situation in countries grappling with acute shortages of N95 masks, this study investigated the possibilities of decontamination and reuse of masks. METHODS: Three N95 masks of different makes (A, B and C) were subjected to six decontamination methods: ultraviolet (UV) irradiation, isopropyl alcohol (IPA) dip, plasma sterilization (Sterrad®), ethylene oxide (ETO, 3M®), dry heat sterilization, and moist heat sterilization (autoclaving). The integrity of the N95 masks was assessed by measuring their particle filtering efficiency at particle sizes ranging 0.3-0.5 microns. RESULTS: All the masks decontaminated with ETO and plasma sterilization retained over 95% particle filtering efficiency. Masks decontaminated using IPA dip and autoclaving showed a drop, and UV irradiation showed variations in particle size efficiency degradation after decontamination. CONCLUSIONS: Plasma sterilization is recommended for decontamination of N95 masks in low-resource settings. ETO is not recommended due to hazards associated with handling of ethylene oxide, although the filtering efficiency was retained. Since the UV irradiation method showed variations in results, evaluation of UV decontamination for N95 masks needs to be performed on a case-by-case basis.

A Review of Recent Evidence for Utilizing Ultraviolet Irradiation Technology to Disinfect Both Indoor Air and Surfaces.

Background: The implementation of "no-touch" technologies such as ultraviolet (UV)-based sanitizers to effectively disinfect the air and high-touch surfaces may be important to keeping working environments and indoor public gathering places, where there may be a higher risk of infection from specific agents, safe for all occupants, particularly with the emergence of highly communicable diseases. UV technologies have been used for many years and are being revisited as one of disinfecting technology to address the SARS-CoV-2 virus that causes COVID-19. Methods: We selected over 20 relevant source documents from approximately 80 papers dating between 1985 and the present (2020) to evaluate the applicability, safety and relative contribution of ultraviolet to disinfect air and surfaces in the built environment. UV-based sanitizers have the potential for effective application when used in conjunction with other disinfecting means. Results: The efficacy of UV-based sanitizer technologies are promising but are dependent on numerous environmental, physical and technical factors. Conclusions: We believe that UV technologies should not be utilized in isolation and should be considered as an adjunct to protocol-driven standard operating procedures for cleaning and disinfection, had hygiene practices, and appropriate use of personal protective equipment (PPE).

Ultraviolet Irradiation Enhances the Microbicidal Activity of Silver Nanoparticles by Hydroxyl Radicals.

It is known that silver has microbicidal qualities; even at a low concentration, silver is active against many kinds of bacteria. Silver nanoparticles (AgNPs) have been extensively studied for a wide range of applications. Alternately, the toxicity of silver to human cells is considerably lower than that to bacteria. Recent studies have shown that AgNPs also have antiviral activity. We found that large amounts of hydroxyl radicals-highly reactive molecular species-are generated when AgNPs are irradiated with ultraviolet (UV) radiation with a wavelength of 365 nm, classified as ultraviolet A (UVA). In this study, we used electron spin resonance direct detection to confirm that UV irradiation of AgNPs produced rapid generation of hydroxyl radicals. As hydroxyl radicals are known to degrade bacteria, viruses, and some chemicals, the enhancement of the microbicidal activity of AgNPs by UV radiation could be valuable for the protection of healthcare workers and the prevention of the spread of infectious diseases.