Prospects of TiO2-based photocatalytic degradation of microplastic leachates related disposable facemask, a major COVID-19 waste

COVID-19 is one of the serious catastrophes that have a substantial influence on human health and the environment. Diverse preventive actions were implemented globally to limit its spread and transmission. Personnel protective equipment (PPE) was an important part of these control approaches. But unfortunately, these types of PPE mainly comprise plastics, which sparked challenges in the management of plastic waste. Disposable face masks (DFM) are one of the efficient strategies used across the world to ward off disease transmission. DFMs can contribute to micro and nano plastic pollution as the plastic present in the mask may degrade when exposed to certain environmental conditions. Microplastics (MPs) can enter the food chain and devastate human health. Recognizing the possible environmental risks associated with the inappropriate disposal of masks, it is crucial to avert it from becoming the next plastic crisis. To address this environmental threat, titanium dioxide (TiO2)-based photocatalytic degradation (PCD) of MPs is one of the promising approaches. TiO2-based photocatalysts exhibit excellent plastic degradation potential due to their outstanding photocatalytic ability, cost efficiency, chemical, and thermal stability. In this review, we have discussed the reports on COVID-19 waste generation, the limitation of current waste management techniques, and the environmental impact of MPs leachates from DFMs. Mainly, the prominence of TiO2 in the PCD and the applications of TiO2-based photocatalysts in MPs degradation are the prime highlights of this review. Additionally, various synthesis methods to enhance the photocatalytic performance of TiO2 and the mechanism of PCD are also discussed. Furthermore, current challenges and the future research perspective on the improvement of this approach have been proposed.

Experimental study of the purification performance of a MopFan-based photocatalytic air cleaning system.

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2, the virus that causes the coronavirus disease (COVID)-19, is primarily transmitted through respiratory droplets which linger in enclosed spaces, often exacerbated by HVAC systems. Although research to improve HVAC handling of SARS-CoV-2 is progressing, currently installed HVAC systems cause problems because they recirculate air and use ineffective filters against virus. This paper details the process of developing a novel method of eliminating air pollutants and suspended pathogens in enclosed spaces using Photocatalytic Oxidation (PCO) technology. It has been previously employed to remove organic contaminants and compounds from air streams using the irradiation of titanium dioxide (TiO2) surfaces with ultraviolet (UV) lights causing the disintegration of organic compounds by reactions with oxygen (O) and hydroxyl radicals (OH). The outcome was two functional prototypes that demonstrate the operation of PCO-based air purification principle. These prototypes comprise a novel TiO2 coated fibre mop system, which provide very large surface area for UV irradiation. Four commercially accessible materials were used for the construction of the mop: Tampico, Brass, Coco, and Natural synthetic. Two types of UV lights were used: 365 nm (UVA) and 270 nm (UVC). A series of tests were conducted that proved the prototype's functionality and its efficiency in lowering volatile organic compounds (VOCs) and formaldehyde (HCHO). The results shown that a MopFan with rotary mop constructed with Coco fibres and utilising UVC light achieves the best VOC and HCHO purification performance. Within 2 h, this combination lowered HCHO by 50% and VOCs by 23% approximately.

Occurrence and Treatment of Antibiotic-Resistant Bacteria Present in Surface Water.

According to the World Health Organization, antibiotic resistance is one of the main threats to global health. The excessive use of several antibiotics has led to the widespread distribution of antibiotic-resistant bacteria and antibiotic resistance genes in various environment matrices, including surface water. In this study, total coliforms, Escherichia coli and enterococci, as well as total coliforms and Escherichia coli resistant to ciprofloxacin, levofloxacin, ampicillin, streptomycin, and imipenem, were monitored in several surface water sampling events. A hybrid reactor was used to test the efficiency of membrane filtration, direct photolysis (using UV-C light emitting diodes that emit light at 265 nm and UV-C low pressure mercury lamps that emit light at 254 nm), and the combination of both processes to ensure the retention and inactivation of total coliforms and Escherichia coli as well as antibiotic-resistant bacteria (total coliforms and Escherichia coli) present in river water at occurrence levels. The membranes used (unmodified silicon carbide membranes and the same membrane modified with a photocatalytic layer) effectively retained the target bacteria. Direct photolysis using low-pressure mercury lamps and light-emitting diode panels (emitting at 265 nm) achieved extremely high levels of inactivation of the target bacteria. The combined treatment (unmodified and modified photocatalytic surfaces in combination with UV-C and UV-A light sources) successfully retained the bacteria and treated the feed after 1 h of treatment. The hybrid treatment proposed is a promising approach to use as point-of-use treatment by isolated populations or when conventional systems and electricity fail due to natural disasters or war. Furthermore, the effective treatment obtained when the combined system was used with UV-A light sources indicates that the process may be a promising approach to guarantee water disinfection using natural sunlight.

Engineering of silk fibroin bio-nanocomposites: A glimpse of advanced research on innovative formulations for potential applications

Silk Fibroin is widely used as a green biomaterial in various fields of research like textiles, biomedical engineering biotechnology, electronics, photonics and energy research. This is because SF can be reconstituted in numerous forms by physical and chemical processes in numbers of studies have attempted to incorporate addition to its unique functional aspects that can be incorporated into SF while maintaining its beneficial natural characters. This new area of biotechnology with bio-nanocomposites is the result of breakthroughs in nanoscience and nanotechnology. SF bio-nanocomposites and their innovative applications for the use of these SF bio-nanocomposites materials have been developed in recent years and these are documented in previous chapters of this book. In this chapter, we report on the advanced research of the engineering of silk fibroin bio-nanocomposites suitable for emerging technologies. Though the formulation of silk fibroin is a natural process, carried out with silkworms, it can be modified with the mulberry leaves which are the silkworm feed. Further, silk fibroin can be changed by doping rare earth elements or by incorporating their nanoparticles at different stages of its formulations. Thus, the properties of silk fibroin are engineered suitably to meet the requirements of various devices with different methods reported recently in the literature. Lastly, the hypothetical applications of silk fibroin in protecting healthcare buildings (hospitals) from pathogenic infections specifically with photocatalytic disinfection of pathogens have been reported in this chapter. This innovative emerging potential application of silk fibroin seems to be an attractive solution to control the spread of communicable diseases like COVID-19. The chapter ends with a report on a recent method based on microwave applications in which formulation of time SF bio-nanocomposites. This modification is reduced synthesis time from 52 hours to 4 hours. This alteration is predicted as a significant step towards commercialization of formulation of SF bio-nanocomposites technologies newly developed in recent years. © 2023 Nova Science Publishers, Inc.

Burdock-Derived Composites Based on Biogenic Gold, Silver Chloride and Zinc Oxide Particles as Green Multifunctional Platforms for Biomedical Applications and Environmental Protection.

Green nanotechnology is a rapidly growing field linked to using the principles of green chemistry to design novel nanomaterials with great potential in environmental and health protection. In this work, metal and semiconducting particles (AuNPs, AgClNPs, ZnO, AuZnO, AgClZnO, and AuAgClZnO) were phytosynthesized through a "green" bottom-up approach, using burdock (Arctium lappa L.) aqueous extract. The morphological (SEM/TEM), structural (XRD, SAED), compositional (EDS), optical (UV-Vis absorption and FTIR spectroscopy), photocatalytic, and bio-properties of the prepared composites were analyzed. The particle size was determined by SEM/TEM and by DLS measurements. The phytoparticles presented high and moderate physical stability, evaluated by zeta potential measurements. The investigation of photocatalytic activity of these composites, using Rhodamine B solutions' degradation under solar light irradiation in the presence of prepared powders, showed different degradation efficiencies. Bioevaluation of the obtained composites revealed the antioxidant and antibacterial properties. The tricomponent system AuAgClZnO showed the best antioxidant activity for capturing ROS and ABTS•+ radicals, and the best biocidal action against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The "green" developed composites can be considered potential adjuvants in biomedical (antioxidant or biocidal agents) or environmental (as antimicrobial agents and catalysts for degradation of water pollutants) applications.

Atomic layer deposition of ZnO on polypropylene nonwovens for photocatalytic antibacterial facemasks.

Addressing respiratory infectious diseases remains one of the main priorities due to the increased risk of exposure caused by population growth, increasing international travel and commerce, and most recently, the COVID-19 outbreak. In the war against respiratory diseases, facemasks are powerful tools to obstruct the penetration of microorganisms, thereby protecting the wearer from infections. Nonetheless, the intercepted microorganisms on the surface of facemasks may proliferate and lead to secondary infection. To solve this problem, atomic layer deposition is introduced to deposit uniform and mechanically robust ZnO layers on polypropylene (PP) nonwoven fabrics, a widely used raw material in fabricating facemasks. The loading of ZnO demonstrates no adverse effects on the separation performance of facemasks, and the filtration efficiency of the facemasks towards different types of nanoparticles remains higher than 98.9%. Moreover, the modified PP nonwoven fabrics are granted with excellent antibacterial activity and photocatalytic sterilization ability, which can inactivate both germ-negative and germ-positive bacteria (E. coliandS. aureus) effectively with and without light illumination. Therefore, the modified PP nonwoven fabrics are potential candidates to be used as the outer layer on facemasks and endow them with photocatalytic antibacterial activity.

Selected dechlorination of triclosan by high-performance g-C3N4/Bi2MoO6 composites: Mechanisms and pathways

Environmental-friendly and efficient strategies for triclosan (TCS) removal have received more attention. Influenced by COVID-19, a large amount of TCS contaminants were accumulated in medical and domestic wastewater discharges. In this study, a unique g-C3N4/Bi2MoO6 heterostructure was fabricated and optimized by a novel and simple method for superb photocatalytic dechlorination of TCS into 2-phenoxyphenol (2-PP) under visible light irradiation. The as-prepared samples were characterized and analyzed by XRD, BET, SEM, XPS, etc. The rationally designed g-C3N4/Bi2MoO6 (4:6) catalyst exhibited notably photocatalytic activity in that more than 95.5% of TCS was transformed at 180 min, which was 3.6 times higher than that of pure g-C3N4 powder. This catalyst promotes efficient photocatalytic electron-hole separation for efficient dechlorination by photocatalytic reduction. The samples exhibited high recyclable ability and the dechlorination pathway was clear. The results of Density Functional Theory calculations displayed the TCS dechlorination selectivity has different mechanisms and hydrogen substitution may be more favorable than hydrogen ion in the TCS dechlorination hydrogen transfer process. This work will provide an experimental and theoretical basis for designing high-performance photocatalysts to construct the systems of efficient and safe visible photocatalytic reduction of aromatic chlorinated pollutants, such as TCS in dechlorinated waters. © 2022 Elsevier Ltd

Inhibitory effects of fucoidan from Laminaria japonica against some pathogenic bacteria and SARS-CoV-2 depend on its large molecular weight.

Fucoidan is a highly sulfated polysaccharide with a wide range of bioactivities, including anti-pathogenic activity. However, the relationship between structure and activity of fucoidan in inhibiting pathogen infections remains unclear. Here, different-molecular-weight fucoidans were prepared by photocatalytic degradation followed by membrane ultrafiltration, and their chemical structures and anti-pathogenic microbiota activity were compared. Results showed that photocatalytic degradation could effectively degrade fucoidan while its structure block and sulfate groups were not destroyed obviously. Fucoidan (90.8 kDa) of 5 mg/mL could inhibit the growth of S. aureus, S. typhimurium and E. coli, but its degradation products, Dfuc1 (19.2 kDa) and Dfuc2 (5.5 kDa), demonstrated lower inhibitory effect. In addition, compared to Dfuc1 and Dfuc2, fucoidan showed stronger capability to prevent the adhesion of S. aureus, L. monocytogenes, V. parahaemolyticus and S. typhimurium to HT-29 cells. Moreover, the inhibitory effect against SARS-CoV-2 and the binding activity to S protein were also positively correlated to molecular weight. These results indicate that natural fucoidan with higher molecular weight are more effective to inhibit these pathogenic bacteria and SARS-CoV-2, providing a better understanding of the relationship between structure and activity of fucoidan against pathogenic microbiota.

Bambusa arundinacea leaves extract-derived Ag NPs: evaluation of the photocatalytic, antioxidant, antibacterial, and anticancer activities.

Bio-fabrication has become a safe approach for silver nanoparticles (Ag NPs). The plant-mediated biosynthesized Ag NPs have emerged as a potential substitute for conventional chemical formation. The biosynthesized Ag NPs were analyzed in terms of crystalline nature, morphology, chemical composition, particle size, stability, size, and shape of the particles. The XRD, FTIR, and TEM analysis indicate the presence of the bioactive secondary metabolites compounds. The bamboo-mediated Ag NPs demonstrated a notable antibacterial efficacy against Gram-positive and Gram-negative pathogenic microorganisms and showed significant antioxidant activity against DPPH free radicals. The degradation of methylene blue at various intervals under solar light irradiation was used to evaluate the photocatalytic performance of Ag NPs. Further, Ag NPs conveyed potent anticancer activity against MCF-7 cell lines with a significant value IC50. The bamboo leaves-mediated Ag NPs synthesized Ag NPs signified strong antibacterial, antioxidant, and anticancer activity; hence, it can be used in various biomedical applications and face mask coating to prevent the coronavirus after successful clinical trials in research laboratories.

Large-scale evaluation of microorganism inactivation by bipolar ionization and photocatalytic devices.

The COVID-19 pandemic has raised awareness in the spread of disease via airborne transmission. As a result, there has been increasing interest in technologies that claim to reduce concentrations of airborne pathogens in indoor environments. The efficacy of many of these emerging technologies is not fully understood, and the testing that has been done is often conducted at a small scale and not representative of applied settings. There is currently no standard test method for evaluating air treatment technologies, making it difficult to compare results across studies or technology types. Here, a consistent testing approach in an operational-scale test chamber with a mock recirculating heating, ventilation, and air conditioning (HVAC) system was used to evaluate the efficacy of bipolar ionization and photocatalytic devices against the non-enveloped bacteriophage MS2 in the air and on surfaces. Statistically significant differences between replicate sets of technology tests and control tests (without technologies active) are apparent after 1 h, ranging to a maximum of 0.88 log10 reduction for the bipolar ionization tests and 1.8 log10 reduction for the photocatalytic device tests. It should be noted that ozone concentrations were elevated above background concentrations in the test chamber during the photocatalytic device testing. No significant differences were observed between control and technology tests in terms of the amount of MS2 deposited or inactivated on surfaces during testing. A standardized, large-scale testing approach, with replicate testing and time-matched control conditions, is necessary for contextualizing laboratory efficacy results, translating them to real-world conditions, and for facilitating technology comparisons.

Polyimide Surface Dielectric Barrier Discharge for Inactivation of SARS-CoV-2 Trapped in a Polypropylene Melt-Blown Filter

Surface dielectric barrier discharge (SDBD) was used to inactivate the infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) trapped in a polypropylene (PP) melt-blown filter. We used a dielectric barrier made of polyimide films with hexagonal holes through which air flowed. In a cylindrical wind tunnel, the SDBD device supplied reactive oxygen species such as ozone to the SARS-CoV-2 trapped in the PP filter. A plaque assay showed that SDBD at an ozone concentration of approximately 51.6 ppm and exposure time of 30 min induced more than 99.78% reduction for filter-adhered SARS-CoV-2. A carbon catalyst after SDBD effectively reduced ozone exhaust below 0.05 ppm. The combination of SDBD, PP filter, and catalyst could be a promising way to decrease the risk of secondary infection due to indoor air purifiers.

Synthesis and Anticancer and Antiviral Activities of C-2'-Branched Arabinonucleosides.

d-Arabinofuranosyl-pyrimidine and -purine nucleoside analogues containing alkylthio-, acetylthio- or 1-thiosugar substituents at the C2' position were prepared from the corresponding 3',5'-O-silylene acetal-protected nucleoside 2'-exomethylenes by photoinitiated, radical-mediated hydrothiolation reactions. Although the stereochemical outcome of the hydrothiolation depended on the structure of both the thiol and the furanoside aglycone, in general, high d-arabino selectivity was obtained. The cytotoxic effect of the arabinonucleosides was studied on tumorous SCC (mouse squamous cell) and immortalized control HaCaT (human keratinocyte) cell lines by MTT assay. Three pyrimidine nucleosides containing C2'-butylsulfanylmethyl or -acetylthiomethyl groups showed promising cytotoxicity at low micromolar concentrations with good selectivity towards tumor cells. SAR analysis using a methyl ß-d-arabinofuranoside reference compound showed that the silyl-protecting group, the nucleobase and the corresponding C2' substituent are crucial for the cell growth inhibitory activity. The effects of the three most active nucleoside analogues on parameters indicative of cytotoxicity, such as cell size, division time and cell generation time, were investigated by near-infrared live cell imaging, which showed that the 2'-acetylthiomethyluridine derivative induced the most significant functional and morphological changes. Some nucleoside analogues also exerted anti-SARS-CoV-2 and/or anti-HCoV-229E activity with low micromolar EC50 values; however, the antiviral activity was always accompanied by significant cytotoxicity.

Photocatalytic degradation of COVID-19 related drug arbidol hydrochloride by Ti3C2 MXene/supramolecular g-C3N4 Schottky junction photocatalyst.

Because of the current COVID-19 outbreak all over the world, the problem of antiviral drugs entering water has become increasingly serious. Arbidol hydrochloride (ABLH) is one of the most widely used drugs against COVID-19, which has been detected in sewage treatment plant sediments after the COVID-19 outbreak. However, there has been no report on the degradation of ABLH. In order to remove ABLH we prepared a novel photocatalyst composed of Ti3C2 MXene and supramolecular g-C3N4 (TiC/SCN) via a simple method. The properties of the material were studied by a series of characterizations (SEM, TEM, EDS, XRD, FTIR, UV-vis, DRS, XPS, TPC, PL, EIS and UPS), indicating the successful preparation of TiC/SCN. Results show that 99% of ABLH was removed within 150 min under visible light illumination by the 0.5TiC/SCN (containing 0.5% of TiC). The performance of 0.5TiC/SCN was about 2.66 times that of SCN resulting from the formation of Schottky junction. Furthermore, under real sunlight illumination, 99.2% of ABLH could be removed by 0.5TiC/SCN within 120 min, which was better than that of commercial P25 TiO2. The pH, anions (NO3- and SO42-) and dissolved organic matter (fulvic acid) could significantly affect the ABLH degradation. Moreover, three possible degradation pathways of ABLH were proposed, and the toxicities of the corresponding by-products were less toxic than ABLH. Meanwhile, findings showed that the superoxide radicals played a major role in the photocatalytic degradation of ABLH by 0.5TiC/SCN. This study provides a well understanding of the mechanism of ABLH degradation and provides a valuable reference for the treatment of ABLH in water.

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.

Atomic layer deposition of chalcogenide thin films: processes, film properties, applications, and bibliometric prospect

The use of atomic layer deposition (ALD) for the deposition of chalcogenide thin films have offered great potential applications in numerous research areas such as change-memory storage, sensors, solar cells, photocatalysis, and batteries, but advancing in these fields of research without understanding the previous developments may not be possible. In this review, both qualitative and quantitative methods were used to establish the development of ALD chalcogenide thin films research for the first time. The qualitative approach was used to study several investigations that utilized the ALD technique in fabricating different chalcogenide thin film materials. The thin films deposition processes, properties, and ap-plications were emphasized. It established the fact that ALD can produce quality chalco-genide thin films for different applications. Similarly, the bibliometrics which is a quantitative method was utilized to analyze ALD chalcogenide thin films based on the published documents retrieved from the Scopus database between the period 1993 and 2021. The influence and quality of published documents were assessed based on the ranking of several authors, authors' countries, institutions, and journals through various indicators like numbers of the published article, total citation and average citation per year, impact factor, and h_index. The bibliometric study revealed the highest annual publication was in 2019 and was found to decrease gradually in 2020 and 2021, which may be due to the outbreak of the covid-19 pandemic. It concluded by creating the prospect for researchers to have knowledge about ALD chalcogenide thin films research, allowing more research focus and selecting an appropriate research collaborative network. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Ozone-enhanced TiO2 nanotube arrays for the removal of COVID-19 aided antibiotic ciprofloxacin from water: Process implications and toxicological evaluation.

The purpose of this study was to evaluate the performance of synthesized TiO2 nanotube arrays (NTAs) for the removal of the COVID-19 aided antibiotic ciprofloxacin (CIP) and the textile dye methylene blue (MB) from model wastewater. Synthesis of TiO2 NTAs showed that anodization potential and calcination temperatures directly influence nanotube formation. The increased anodization potential from 10 to 40 V resulted in the development of larger porous nanotubes with a diameter of 36-170 nm, while the collapse of the tubular structure was registered at the highest applied potential. Furthermore, it was found that the 500 °C calcination temperature was the most prominent for the formation of the most photocatalytically active TiO2 NTAs, due to the optimal anatase/rutile ratio of 4.60. The degradation of both model compounds was achieved with all synthesized TiO2 NTAs; however, the most photocatalytically active NTA sample was produced at 30 V and 500 °C. Compared to photocatalysis, CIP degradation was greatly enhanced by 5-25 times when ozone was introduced to the photocatalytic cell (rates 0.4-4.2 × 10-1 min-1 versus 0.07-0.2 × 10-1 min-1). This resulted in the formation of CIP degradation by-products, with different mass-to-charge ratios from [M+H]+ 346 to 273 m/z. Even though the CIP degradation pathway is rather complex, three main mechanisms, decarboxylation, hydroxylation reaction, and piperazine ring cleavage, were proposed and explained. Furthermore, treated samples were placed in contact with the crustaceans Daphnia magna. It was found that 100% mortality was achieved when approximately 60% of the remaining TOC was present in the samples, indicating that toxic degradation by-products were formed.

Electrospun nanofibrous membrane with antibacterial and antiviral properties decorated with Myoporum bontioides extract and silver-doped carbon nitride nanoparticles for medical masks application.

Public health safety issues have been plaguing the world since the pandemic outbreak of coronavirus disease (COVID-19). However, most personal protective equipments (PPE) do not have antibacterial and anti- toxicity effects. In this work, we designed and prepared a reusable, antibacterial and anti-toxicity Polyacrylonitrile (PAN) based nanofibrous membrane cooperated with Ag/g-C3N4 (Ag-CN), Myoporum.bontioides (M. bontioides) plant extracts and Ag nanoparticles (NPs) by an electrospinning-process. The SEM and TEM characterization revealed the formation of raised, creased or wrinkled areas on the fiber surface caused by the Ag nanoparticles, the rough surface prevented the aerosol particles on the fiber surface from sliding and stagnating, thus providing excellent filtration performance. The PAN/M. bontioides/Ag-CN/Ag nanofibrous membrane could be employed as a photocatalytic bactericidal material, which not only degraded 96.37% of methylene blue within 150 min, but also exhibited the superior bactericidal effect of 98.65 ± 1.49% and 97.8 ± 1.27% against E. coli and S. aureus, respectively, under 3 hs of light exposure. After 3 cycles of sterilization experiments, the PAN/M. bontioides/Ag-CN/Ag nanofibrous membrane maintained an efficient sterilization effect. Molecular docking revealed that the compounds in M. bontioides extracts interacted with neo-coronavirus targets mainly on Mpro and RdRp proteins, and these compounds had the strongest docking energy with Mpro protein, the shortest docking radius, and more binding sites for key amino acids around the viral protein targets, which influenced the replication and transcription process of neo-coronavirus. The PAN/M.bontioides/Ag-CN/Ag nanofibrous membrane also performed significant inhibition of influenza A virus H3N2. The novel nanofiber membrane is expected to be applied to medical masks, which will improve human isolation and protection against viruses.

Application of Nanotechnology for Virus Inactivation in Water: Implications for Transmission over line Blocking of the Novel Coronavirus SARS over line CoV over line 2

The novel coronavirus pneumonia epidemic (COVID over line 19) brings a serious threat to the development of human society and the health of human beings. Due to the stability of the severe acute respiratory syndrome coronavirus 2 ( SARS over line CoV over line 2) in urban sewage, which has become one of the virus pollution sources, it has been a focus how to eliminate the existing virus in water. SARS over line CoV over line 2 structurally consists of RNA chains and protein capsids, and thus can be inactivated via reactive oxygen species ( ROS) attack. Moreover, block of biochemical metabolism and destruction of virus structure are also effective inactivation methods for SARS over line CoV over line 2 inactivation. Nanomaterials exhibit surface and interface effects, specific microstructure and excellent physicochemical properties, implying their high application potential in SARS over line CoV over line 2 inactivation. In this study, we overall review application of nanotechnologies for SARS over line CoV over line 2 inactivation, including photocatalysis, heterogeneous catalytic oxidation, ion toxicity induced inactivation, and structural effects inactivation method. Furthermore, based on the structural composition, as well as survival and transmission characteristics of SARS over line CoV over line 2 in water environment, the application potential of various nanotechnologies for SARS over line CoV over line 2 inactivation are deeply discussed. This study can provide a theoretical basis and practical reference for the application of nanotechnology for the SARS over line CoV over line 2 inactivation and the secondary transmission interruption in water.

Evaluation of the multifunctional activity of silver bionanocomposites in environmental remediation and inhibition of the growth of multidrug-resistant pathogens

Synthesis of bio-based environmental remedial and antimicrobial products is an urgent need of the 21st century in the COVID-19 pandemic world. Keeping this in mind, cellulose-supported Ag bionanocomposites (AGC NCs) were synthesized by using cellulose as a reducing and stabilizing agent. AGC NCs showed potential antimicrobial activity against Candida albicans, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis with a MIC of 15, 15, 35, 15, and 30 mu g ml(-1) respectively. AGC NCs efficiently degraded harmful dyes, Orange G, Phenol red, Brilliant blue FCF, Giemsa stain, Neutral red, and 2-nitro aniline in the presence of sunlight with a rate constant of 0.229 x 10(-2) min(-1), 1.147 x 10(-2) L mol(-1) min(-1), 0.447 x 10(-2) L mol(-1) min(-1), 4.144 x 10(-2) mol L-1 min(-1), 0.317 x 10(-2) L mol(-1) min(-1), and 0.785 x 10(-2) L mol(-1) min(-1) in 60 min respectively. AGC NCs also showed efficient antioxidant activity in DPPH assay with an IC50 value of 52.67 mu g ml(-1). Formation of Ag NPs was confirmed by observing the UV-Visible absorption peak at 418 nm. The FCC structure of AGC NCs was confirmed by the X-ray diffraction (XRD) pattern with well-defined peaks at angles 38.24 degrees, 44.40 degrees, 64.64 degrees, and 77.28 degrees corresponding to the planes 111, 200, 220, and 311, with a d-spacing of 2.35, 2.04, 1.44, and 1.23 (JCPDS no. 00-001-1164). The presence of cellulose in AGC NCs was determined by Fourier transform infrared spectroscopy (FTIR) with bands at 3421.90 cm(-1) and 2899.3 cm(-1) due to O-H stretching and the methylene (-CH2-) group respectively and at 1076-1023 cm(-1) and 903 cm(-1) due to -C-O-C- pyranose ring skeletal vibration and beta-glycosidic linkages. The morphology, shape and size (13.21 nm), and elemental composition of the nanocomposites were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS) respectively. The thermal properties (exothermic peaks appear at 335 degrees C and 440 degrees C due to the thermal degradation of Ag NPs and cellulose respectively), surface area (13.892 m(2) g(-1)), stability (-18.43 +/- 0.850 mV), and hydrodynamic diameter (399.10 +/- 30.49 nm) and polydispersity index (PDI) value (0.565 +/- 0.193) of the composites were determined by thermogravimetric analysis (TGA) and differential thermal analysis (DTA), Brunauer-Emmett-Teller (BET) method, Zeta potential studies, and dynamic light scattering (DLS) respectively.

Virucidal Properties of Photocatalytic Coating on Glass against a Model Human Coronavirus.

The antimicrobial properties of photocatalysts have long been studied. However, most of the available literature describes their antibacterial properties, while knowledge of their antiviral activity is rather scarce. Since the outset of the coronavirus disease 2019 (COVID-19) pandemic, an increasing body of research has suggested their antiviral potential and highlighted the need for further research in this area. In this study, we investigated the virucidal properties of a commercial TiO2-coated photocatalytic glass against a model human coronavirus. Our findings demonstrate that the TiO2-coated glass consistently inactivates coronaviruses upon contact under daylight illumination, in a time-dependent manner. A 99% drop in virus titer was achieved after 3.9 h. The electron micrographs of virus-covered TiO2-glass showed a reduced number of virions compared to control glass. Morphological alterations of TiO2-exposed viruses included deformation, disruption of the viral envelope, and virion ghosts, endorsing the application of this material in the construction of protective elements to mitigate the transmission of viruses. To the best of our knowledge, this is the first report showing direct visual evidence of human coronaviruses being damaged and morphologically altered following exposure to this photocatalyst. IMPORTANCE Surface contamination is an important contributor to SARS-CoV-2 spread. The use of personal protective elements and physical barriers (i.e., masks, gloves, and indoor glass separators) increases safety and has proven invaluable in preventing contagion. Redesigning these barriers so that the virus cannot remain infectious on them could make a difference in COVID-19 epidemiology. The introduction of additives with virucidal activity could potentiate the protective effects of these barriers to serve not only as physical containment but also as virus killers, reducing surface contamination after hand touch or aerosol deposition. We performed in-depth analysis of the kinetics of photocatalysis-triggered coronavirus inactivation on building glass coated with TiO2. This is the first report showing direct visual evidence (electron microscopy) of coronaviruses being morphologically damaged following exposure to this photocatalyst, demonstrating the high potential of this material to be incorporated into daily-life high-touch surfaces, giving them an added value in decelerating the virus spread.