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Efficient and quick inactivation of SARS coronavirus and other microbes exposed to the surfaces of some metal catalysts



To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were pressed into wafers. One hundred microL 10(6) TCID50/mL SARS-CoV, 100 microL 10(6) PFU/mL recombinant baculovirus expressing hamster's prion protein (haPrP) protein and roughly 10(6) E. coli were slowly dropped onto the surfaces of the catalyst wafers and exposed for 5 and 20 min, respectively. After eluted from the surfaces of wafers, the infectivity of viruses and propagation of bacteria were measured. The expression of PrP protein was determined by Western blot. The morphological changes of bacteria were observed by electronic microscopy. After exposure to the catalysts surfaces for 5 and 20 min, the infectivity of SARS-CoV in Vero cells and baculovirus in Sf9 cells dropped down to a very low and undetectable level, and no colony was detected using bacteria culture method. The expression of haPrP protein reduced to 21.8% in the preparation of Sf9 cells infected with recombinant baculovirus exposed for 5 min and was undetectable exposed for 20 min. Bacterial membranes seemed to be cracked and the cytoplasm seemed to be effluent from cell bodies. Exposures to the surfaces of Ag/Al2O3 and Cu/Al2O3 destroy the replication and propagation abilities of SARS-CoV, baculovirus and E. coli. Inactivation ability of metal catalysts needs to interact with air, utilizing oxygen molecules in air. Efficiently killing viruses and bacteria on the surfaces of the two metal catalysts has a promising potential for air-disinfection in hospitals, communities, and households.
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... Studies have demonstrated the virucidal efficacy of AgNP against human pathogenic viruses, including enveloped viruses such as respiratory syncytial virus (RSV), influenza virus, hepatitis B virus (HBV), and human immunodeficiency virus (HIV), as well as non-enveloped viruses such as human norovirus [2]. In addition, Ag + has been shown to possess virucidal efficacy against severe acute respiratory syndrome coronavirus (SARS-CoV) [21] and SARS-CoV-2 [22,23]. AgNP formulations have been proposed for cleaning inanimate surfaces to efficiently control the ongoing COVID-19 pandemic [23]. ...
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This chapter focuses on viral efficacy evaluations of silver ion (Ag+) formulations against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus associated with the COVID-19 pandemic and feline calicivirus (FCV), a surrogate for human norovirus. The chapter discusses the proposed mechanism of inactivation, with reference to some previously published articles. In addition, it discusses the background/current trend/future view of Ag+ products that have been used widely as surface/environment disinfectants in daily life all over the world. In efficacy studies performed by using the standardized ASTM E1052 methodology, it was found that Ag+ formulated with a low concentration (26% w/w) of ethanol displayed virucidal activity against SARS-CoV-2 and FeCV. These formulations might be useful for preventing the transmission of such viruses and limiting the outbreaks of emerging infectious diseases caused by coronaviruses and caliciviruses. To our knowledge, this is the first report describing the virucidal efficacy of an Ag+ formulation, evaluated by using the standardized ASTM E1052 methodology, for inactivating SARS-CoV-2. Some characteristics of Ag+-based virucides are discussed in this research report/minireview.
... 10,11 Over the years, considerable research has been conducted to investigate antiviral activities of copper nanoparticles (Cu NPs). [12][13][14] Copper-based materials have been vigorously investigated for their rapid and high inactivation efficacy against pathogens such as the inuenza virus (H1N1) 15 and coronaviruses such as severe acute respiratory syndrome coronavirus (SARS-CoV) 16 and human coronaviruses. 17 Consequently, copper was selected as the model antibacterial agent in this study due to its cost-effective and signicant antiviral behavior. ...
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The widespread transmission of coronavirus disease (COVID-19) poses an urgent need for air filter development to prevent pathogens from spreading in indoor spaces. This paper aimed to introduce an in-situ...
... In another experimental and theoretical study, the authors calculated the Gibbs free energies of the complexes formed between Ag + ions, Ag atoms, and two-atom Ag clusters with the amino acid's various functional groups [7,8,11]. Some theoretical and experimental studies on amino acids and silver ions have been performed by other authors [1,[11][12][13][14]. In one of the works [6,9] the silver ion complex, Ag + , was examined with amino acid using hybrid density functional theory at the B3LYP/DZVP level. ...
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The world has face the COVID-19 pandemic which has already caused millions of death. Due to the urgency in fighting the virus, we study five residues of free amino acids present in the structure of the SARS-CoV-2 spike protein (S). We investigated the spontaneous interaction between amino acids and silver ions (Ag +), considering these ions as a virucide chemical agent for SARS-CoV-2. The amino acid-Ag + systems were investigated in a gaseous medium and a simulated water environment was described with a continuum model (PCM) the calculations were performed within the framework of density functional theory (DFT). Calculations related to the occupied orbitals of higher energy showed that Ag + has a tendency to interact with the nitrile groups (-NH). The negative values of the Gibbs free energies show that the interaction process between amino acids-Ag + in both media occurs spontaneously. There is a decrease in Gibbs free energy from the amino acid-Ag + interactions immersed in a water solvation simulator.
The COVID-19 pandemic has demonstrated the need for versatile and robust countermeasures against viral threats. A wide range of viruses, including SARS-CoV-2, the virus that causes COVID-19, can be deactivated by metal and metal-oxide surface coatings. However, such coatings are expensive and cannot easily be retrofitted to existing infrastructure. Low-cost materials to halt the propagation of a variety of viruses must be produced with minimal quantities of expensive precursors. In this regard, we show that commercially available copper oxide nanoparticle suspensions can deactivate more than 99.55% of the human coronavirus 229E in 30 min, confirming the particles' efficiency as a fast antiviral material.
Coronavirus disease 2019 (COVID-19) infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global burden to public health that manifests various symptoms, including self-limiting upper respiratory disorder, severe pneumonia, multi-organ failure, and even death. Thus, efficient approaches to tackle the rapid biological diversity and mutations of coronaviruses (CoVs) are required. Recently, nanotechnology approaches have enabled control of virus transmission by offering efficient personal protective equipment, antiviral surface coatings, and disinfectants. Besides, nanotechnology could be used in viral infection sampling, sample processing, amplification, and sensing to create rapid, sensitive, and accurate diagnostic tests. Nanomaterials have been increasingly used to deliver potential therapeutic agents, vaccines, and artificial viruses because of their certain properties such as high surface-to-volume ratio, specific optical, antiviral action, drug encapsulation, nanoscale biorecognition, and controlled release properties. This chapter covers nanotechnology-based approaches for preventing, diagnosing, and treating CoV infections with an emphasis on SARS-CoV-2.
The concept of a porous [email protected] photocatalytic structure with less stable component as a core (CuxO) and a firm one (TiO2) as a shell having unique antimicrobial properties has been introduced in this study. The Cux[email protected]2 photocatalysts with different compositions (CuxO content from 1 to 50 wt.%), and thus various morphologies (a broad shell of titania composed of fine nanoparticles or incomplete coverage of CuxO core) and properties (oxidation states of elements, crystallite size, photoabsorption properties), have been prepared by water-in-oil microemulsion method. The materials have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS) and scanning transmission electron microscopy (STEM). The antibacterial tests have been performed via suspension method for Escherichia coli (E. coli) K12 in the dark and under UV (300–420 nm) or vis (> 420 nm) irradiation. It has been found that the morphology, which influences also other properties, e.g., surface charge and composition (being responsible for an efficient photocatalyst adsorption on the bacteria surface), is decisive for the overall antibacterial performance. The photocatalyst with the lowest content of copper (1%), and thus with a broad titania shell, exhibits the highest activity in the dark, probably due to the largest content of Cu2O. Interestingly, irradiation of this sample with any photons (UV or vis) is detrimental for antibacterial effect, probably due to the change of oxidation state of copper. In contrast, the irradiation significantly enhances the bactericidal activity of samples with larger content of CuxO (10 and 50%), and thus being not completely covered with titania, probably due to enhanced photocatalytic activity (Z-scheme mechanism) under UV irradiation, and electrostatic attractions between positively and negatively charged copper and bacteria, respectively, under vis light.
Water is linked to every aspect of our life, and the nexus between water and health is well-documented. Lack of access to clean water and waterborne diseases is a significant cause of human misery. Pesticides are a group of chemicals widely detected in water bodies, mainly due to their indiscriminate use in the agricultural sector. Due to possible entry into human and animal food chains, health hazards posed by pesticides have become a considerable area of concern worldwide. Nevertheless, the production and use of pesticides are increasing, and the global pesticide market is expected to reach 24.6 billion USD by 2020–2024. Given the widespread occurrence and potential toxicity, many treatment technologies are in place to treat pesticide-contaminated water. However, the diverse chemical nature of the pesticides and the stringent regulations in drinking water standards, 0.1 μg/L for a single pesticide and 0.5 μg/L for the sum of all pesticides, limit the use of many existing treatment systems. The advancement in nanoscience and nanotechnology suggests that nanoscale materials, especially nanocarbon and its derivatives, are promising candidates for scavenging pesticides in water. This chapter reviews the literature on various nanoscale carbons with exciting properties and their applications for treating pesticide-laden drinking water. The mechanism of removal, challenges, prospects, and future development in the area is discussed. This chapter also covers the origin, occurrence of pesticides in water bodies, and their human and ecological health impacts.
Clean drinking water is absolutely essential for our survival. Unfortunately, drinking water resources are being polluted in a variety of ways. Conventional water purification technologies are generally not efficient. To mitigate this problem, scientists around the world are working to develop new cost-effective, environment-friendly technologies. Nanomaterials with extraordinary physical, chemical, mechanical, and morphologic properties offer a potential solution to water pollution issues. In this chapter, we point out some basic information on various sources of contamination and their effects on human beings and environment, differences between wastewater and drinking water treatment processes, and limitations of conventional water treatment technologies. We describe how nanophotocatalyst, nanomembrane, nanoreactor, and nanoadsorbent can decontaminate polluted water sources. In addition, we discuss how to remove five selected pollutants (arsenic, lead, pharmaceutical, per- and polyfluoroalkyl substances, and corona viruses) from water by various nanomaterials. Finally, we show some limitations of using nanomaterials for water treatment.
Emergence and re-emergence of four types of severely infectious viruses have claimed significant numbers of lives when anthropogenic activities contribute to the mutagenesis of these pathogens and infectivity of these pathogens has been noticeably altered. However, both point and non-point sources can transport these viruses in water treatment and resource recovery facilities (RRF) where the presence of these pathogens in aerosolized form or in suspension can cause astronomical public health concerns. Hence, numerous scientific studies have been reviewed to comprehend the possible inactivation mechanisms of those viruses in aqueous phase where thermal-, photo-, and chemical-inactivation have confirmed their effectiveness in restraining those viruses and inactivation mechanisms are the major focuses to apprehend the quick and cost-effective virus removal process from water and RRF. Although practical applications of nano-sized disinfectants have challenged researchers, those disinfectants can completely kill the viruses and hamper RNA/DNA replication without any sign of reactivation or repair. Moreover, limitations and future research potential are discussed so that efficacious strategic management for a treatment facility can be developed at the forefront of fighting tactics against an epidemic or a pandemic. Enumerations, besides state-of-the-art detection techniques with gene sequences, are mentioned for these viruses. HIGHLIGHTS UV and FUVC can effectively inactivate corona- and ebolaviruses.; Nanostructured disinfectants have potential to inactivate the emerging viruses by forming ROSs in both solid and liquid phase.; Disintegration of capsid protein and nucleic acid is imperative to inactivate viruses.; A strategic framework to develop early warning in the community should be established.; This kind of review manuscript is extremely rare.;
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In March 2003, a novel coronavirus (SARS-CoV) was discovered in association with cases of severe acute respiratory syndrome (SARS). The sequence of the complete genome of SARS-CoV was determined, and the initial characterization of the viral genome is presented in this report. The genome of SARS-CoV is 29,727 nucleotides in length and has 11 open reading frames, and its genome organization is similar to that of other coronaviruses. Phylogenetic analyses and sequence comparisons showed that SARS-CoV is not closely related to any of the previously characterized coronaviruses.
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Information on the clinical features of the severe acute respiratory syndrome (SARS) will be of value to physicians caring for patients suspected of having this disorder. We abstracted data on the clinical presentation and course of disease in 10 epidemiologically linked Chinese patients (5 men and 5 women 38 to 72 years old) in whom SARS was diagnosed between February 22, 2003, and March 22, 2003, at our hospitals in Hong Kong, China. Exposure between the source patient and subsequent patients ranged from minimal to that between patient and health care provider. The incubation period ranged from 2 to 11 days. All patients presented with fever (temperature, >38 degrees C for over 24 hours), and most presented with rigor, dry cough, dyspnea, malaise, headache, and hypoxemia. Physical examination of the chest revealed crackles and percussion dullness. Lymphopenia was observed in nine patients, and most patients had mildly elevated aminotransferase levels but normal serum creatinine levels. Serial chest radiographs showed progressive air-space disease. Two patients died of progressive respiratory failure; histologic analysis of their lungs showed diffuse alveolar damage. There was no evidence of infection by Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella pneumophila. All patients received corticosteroid and ribavirin therapy a mean (+/-SD) of 9.6+/-5.42 days after the onset of symptoms, and eight were treated earlier with a combination of beta-lactams and macrolide for 4+/-1.9 days, with no clinical or radiologic efficacy. SARS appears to be infectious in origin. Fever followed by rapidly progressive respiratory compromise is the key complex of signs and symptoms from which the syndrome derives its name. The microbiologic origins of SARS remain unclear.
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A worldwide outbreak of severe acute respiratory syndrome (SARS) has been associated with exposures originating from a single ill health care worker from Guangdong Province, China. We conducted studies to identify the etiologic agent of this outbreak. We received clinical specimens from patients in seven countries and tested them, using virus-isolation techniques, electron-microscopical and histologic studies, and molecular and serologic assays, in an attempt to identify a wide range of potential pathogens. None of the previously described respiratory pathogens were consistently identified. However, a novel coronavirus was isolated from patients who met the case definition of SARS. Cytopathological features were noted in Vero E6 cells inoculated with a throat-swab specimen. Electron-microscopical examination revealed ultrastructural features characteristic of coronaviruses. Immunohistochemical and immunofluorescence staining revealed reactivity with group I coronavirus polyclonal antibodies. Consensus coronavirus primers designed to amplify a fragment of the polymerase gene by reverse transcription-polymerase chain reaction (RT-PCR) were used to obtain a sequence that clearly identified the isolate as a unique coronavirus only distantly related to previously sequenced coronaviruses. With specific diagnostic RT-PCR primers we identified several identical nucleotide sequences in 12 patients from several locations, a finding consistent with a point-source outbreak. Indirect fluorescence antibody tests and enzyme-linked immunosorbent assays made with the new isolate have been used to demonstrate a virus-specific serologic response. This virus may never before have circulated in the U.S. population. A novel coronavirus is associated with this outbreak, and the evidence indicates that this virus has an etiologic role in SARS. Because of the death of Dr. Carlo Urbani, we propose that our first isolate be named the Urbani strain of SARS-associated coronavirus.
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We sequenced the 29,751-base genome of the severe acute respiratory syndrome (SARS)-associated coronavirus known as the Tor2 isolate. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses, including two human coronaviruses, HCoV-OC43 and HCoV-229E. Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of coronaviruses. The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using polymerase chain reaction and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.
We show that dissociative oxygen adsorption on Ag(001) induces below room temperature a missing row 22×2 reconstruction of the substrate. As demonstrated by the analysis of the photoelectron diffraction patterns, the oxygen atoms sit thereby in a c(2×2) arrangement in the previous fourfold hollow sites nearly coplanar with the Ag atoms, while rows of substrate atoms are removed along the [100] directions. Annealing the crystal above 350 K restores the p(1×1) symmetry and the oxygen moves to 0.6 Å above the fourfold hollow site. It becomes then more oxidic in nature, as demonstrated by the shift of the O 1s level from 530.3 eV to 528.3 eV. The phase transition affects also the O 2s and O 2p levels as well as the surface component of Ag 3d5/2. The vibrational frequency of the oxygen adatoms against the surface decreases at the phase transition, in accord with the larger adsorption distance. The higher temperature phase is active towards CO and C2H4 oxidation, while the low-temperature phase is not. When cooling the sample below room temperature the reconstructed phase is restored. The time constant of this process as well as the chemical reactivity of the high-temperature phase are weakly reproducible since they depend on the previous history, i.e., presumably on the subsurface oxygen content of the sample.
The deactivation and regeneration phenomenon during room temperature CO oxidation was studied over a Au/γ-Al2O3 catalyst, which was as active as the most active supported Au catalysts reported in the literature. The initial rapid loss of activity could be prevented if either hydrogen or water vapor was present in the reaction mixture. Otherwise, it could be recovered by exposure of the deactivated catalyst to either hydrogen or water vapor at room temperature. Thermal treatment above 100 °C in a dry atmosphere also deactivated the catalyst. These results suggested that hydroxyl group, most likely associated with a Au(I) cation, is associated with the active site and support the proposal that the active site is an ensemble of Au+OH− together with Au(0) atoms. The CO oxidation reaction was proposed to proceed via the insertion of CO into the Au+OH− bond to form a hydroxycarbonyl, which is oxidized to a bicarbonate. Decarboxylation of the bicarbonate completes the reaction cycle.
An idea of the chemical reconstruction caused by the formation of quasi-compounds and their self-assembly is defined. New surfaces were fabricated by combining the reaction of the quasi-compounds and their self-assembly. A quasi-compound of (CuO) strings was grown in the [11̄0] direction on Ag(110) by the reaction of (AgO) strings with Cu atoms, which brought about a reversible reaction of (CuO)⇄(Cu)6+O2. By the reaction of (AgO) strings with CO2, a composite structure of (AgO) and (AgCO3) was established on the Ag(110) surface. When Cu atoms were vaporized on this composite surface, the (AgO) strings reacted selectively with Cu atoms, and (CuO) strings grew in the [11̄0] direction. Interestingly, an opposite selective reaction occurred when the composite surface was scanned with a W tip coated with Cu; that is, Cu atoms react selectively with carbonate species. These phenomena suggest that the chemical reaction and the chemical transportation reaction will make realize atomic scale surface fabrication possible. The photochemical reaction of a quasi-compound was also attained on a composite surface of (AgO) and (Ag2N) strings on the Ag(110) surface, where the (AgO) strings were selectively erased by illumination.
Conversion of the PrP cellular form (PrP(C)) to the pathogenic form (PrP(Sc)) is the key step in the pathogenesis of transmissible spongiform encephalophathies. Although the mechanism of conformational conversion of PrP proteins remains uncertain, the cell-free conversion reaction and other in vitro PrP amplification tests allow it to be studied under the much quicker and simpler conditions than those of transmission bioassay in vivo. Using baculovirus expression system, wild-type hamster (HaPrP) and human PrP (HuPrP), as well as D178N mutated human PrP (HuPrPm178) were expressed in HIS-fusion form. After 35S-methionine labeling and purification with Ni-NTA agarose affinity chromatography, individual expressed PrP proteins were mixed with PrP(Sc) isolated from hamster brain tissue infected with scrapie 263K. Protease-resistant isoform was detected in the homologous HaPrP reaction, but not in the two heterologous HuPrP preparations, implying a species-specific molecular recognition between PrP(C) and PrP(Sc). HIS-tag in HIS-HaPrP seems to have little effect on the formation of protease-resistant protein in this preparation. This system proposes a simple and protein productive-enriched way for cell-free conversion of prion proteins, as the replacement of native or genetic engineering expressed sole PrP(C) from mammalian or non-mammalian sources.
An outbreak of severe acute respiratory syndrome (SARS) has been reported in Hong Kong. We investigated the viral cause and clinical presentation among 50 patients. We analysed case notes and microbiological findings for 50 patients with SARS, representing more than five separate epidemiologically linked transmission clusters. We defined the clinical presentation and risk factors associated with severe disease and investigated the causal agents by chest radiography and laboratory testing of nasopharyngeal aspirates and sera samples. We compared the laboratory findings with those submitted for microbiological investigation of other diseases from patients whose identity was masked. Patients' age ranged from 23 to 74 years. Fever, chills, myalgia, and cough were the most frequent complaints. When compared with chest radiographic changes, respiratory symptoms and auscultatory findings were disproportionally mild. Patients who were household contacts of other infected people and had older age, lymphopenia, and liver dysfunction were associated with severe disease. A virus belonging to the family Coronaviridae was isolated from two patients. By use of serological and reverse-transcriptase PCR specific for this virus, 45 of 50 patients with SARS, but no controls, had evidence of infection with this virus. A coronavirus was isolated from patients with SARS that might be the primary agent associated with this disease. Serological and molecular tests specific for the virus permitted a definitive laboratory diagnosis to be made and allowed further investigation to define whether other cofactors play a part in disease progression.
Ralph A. Tripp, Lia M. Haynes, Deborah Moore, Barbara Anderson, Azaibi Tamin, Brian H. Harcourt, Les P. Jones, Mamadi Yilla, Gregory J. Babcock, Thomas Greenough, Donna M. Ambrosino, Rene Alvarez, Justin Callaway, Sheana Cavitt, Kurt Kamrud, Harold Alterson, Jonathan Smith, Jennifer L. Harcourt, Congrong Miao, Raj Razdan, James A. Comer, Pierre E. Rollin, Thomas G. Ksiazek, Anthony Sanchez, Paul A. Rota, William J. Bellini, Larry J. Anderson. (2005) Monoclonal antibodies to SARS-associated coronavirus (SARS-CoV): Identification of neutralizing and antibodies reactive to S, N, M and E viral proteins. Journal of Virological Methods 128, 21-28 CrossRef