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1.
Molecules ; 28(8)2023 Apr 20.
Article in English | MEDLINE | ID: covidwho-2299701

ABSTRACT

The development of very efficient and safe non-viral vectors, constituted mainly by cationic lipids bearing multiple charges, is a landmark for in vivo gene-based medicine. To understand the effect of the hydrophobic chain's length, we here report the synthesis, and the chemico-physical and biological characterization, of a new term of the homologous series of hydrogenated gemini bispyridinium surfactants, the 1,1'-bis-dodecyl-2,2'-hexane-1,6-diyl-bispyridinium chloride (GP12_6). Moreover, we have collected and compared the thermodynamic micellization parameters (cmc, changes in enthalpy, free energy, and entropy of micellization) obtained by isothermal titration calorimetry (ITC) experiments for hydrogenated surfactants GP12_6 and GP16_6, and for the partially fluorinated ones, FGPn (where n is the spacer length). The data obtained for GP12_6 by EMSA, MTT, transient transfection assays, and AFM imaging show that in this class of compounds, the gene delivery ability strictly depends on the spacer length but barely on the hydrophobic tail length. CD spectra have been shown to be a useful tool to verify the formation of lipoplexes due to the presence of a "tail" in the 288-320 nm region attributed to a chiroptical feature named ψ-phase. Ellipsometric measurements suggest that FGP6 and FGP8 (showing a very interesting gene delivery activity, when formulated with DOPE) act in a very similar way, and dissimilar from FGP4, exactly as in the case of transfection, and confirm the hypothesis suggested by previously obtained thermodynamic data about the requirement of a proper length of the spacer to allow the molecule to form a sort of molecular tong able to intercalate DNA.


Subject(s)
Chlorides , Hexanes , Gene Transfer Techniques , Surface-Active Agents/chemistry
2.
Int J Pharm X ; 5: 100174, 2023 Dec.
Article in English | MEDLINE | ID: covidwho-2258117

ABSTRACT

The most prevalent conditions among ocular surgery and COVID-19 patients are fungal eye infections, which may cause inflammation and dry eye, and may cause ocular morbidity. Amphotericin-B eye drops are commonly used in the treatment of ocular fungal infections. Lactoferrin is an iron-binding glycoprotein with broad-spectrum antimicrobial activity and is used for the treatment of dry eye, conjunctivitis, and ocular inflammation. However, poor aqueous stability and excessive nasolacrimal duct draining impede these agens' efficiency. The aim of this study was to examine the effect of Amphotericin-B, as an antifungal against Candida albicans, Fusarium, and Aspergillus flavus, and Lactoferrin, as an anti-inflammatory and anti-dry eye, when co-loaded in triblock polymers PLGA-PEG-PEI nanoparticles embedded in P188-P407 ophthalmic thermosensitive gel. The nanoparticles were prepared by a double emulsion solvent evaporation method. The optimized formula showed particle size (177.0 ± 0.3 nm), poly-dispersity index (0.011 ± 0.01), zeta-potential (31.9 ± 0.3 mV), and entrapment% (90.9 ± 0.5) with improved ex-vivo pharmacokinetic parameters and ex-vivo trans-corneal penetrability, compared with drug solution. Confocal laser scanning revealed valuable penetration of fluoro-labeled nanoparticles. Irritation tests (Draize Test), Atomic force microscopy, cell culture and animal tests including histopathological analysis revealed superiority of the nanoparticles in reducing signs of inflammation and eradication of fungal infection in rabbits, without causing any damage to rabbit eyeballs. The nanoparticles exhibited favorable pharmacodynamic features with sustained release profile, and is neither cytotoxic nor irritating in-vitro or in-vivo. The developed formulation might provide a new and safe nanotechnology for treating eye problems, like inflammation and fungal infections.

3.
J Colloid Interface Sci ; 634: 963-971, 2023 Mar 15.
Article in English | MEDLINE | ID: covidwho-2244438

ABSTRACT

HYPOTHESIS: Virus-like particles (VLPs) are promising scaffolds for developing mucosal vaccines. For their optimal performance, in addition to design parameters from an immunological perspective, biophysical properties may need to be considered. EXPERIMENTS: We investigated the mechanical properties of VLPs scaffolded on the coat protein of Acinetobacter phage AP205 using atomic force microscopy and small angle X-ray scattering. FINDINGS: Investigations showed that AP205 VLP is a tough nanoshell of stiffness 93 ± 23 pN/nm and elastic modulus 0.11 GPa. However, its mechanical properties are modulated by attaching muco-inert polyethylene glycol to 46 ± 10 pN/nm and 0.05 GPa. Addition of antigenic peptides derived from SARS-CoV2 spike protein by genetic fusion increased the stiffness to 146 ± 54 pN/nm although the elastic modulus remained unchanged. These results, which are interpreted in terms of shell thickness and coat protein net charge variations, demonstrate that surface conjugation can induce appreciable changes in the biophysical properties of VLP-scaffolded vaccines.


Subject(s)
Bacteriophages , COVID-19 , Vaccines, Virus-Like Particle , Humans , Vaccines, Virus-Like Particle/chemistry , RNA, Viral , SARS-CoV-2
4.
Nano Lett ; 23(4): 1496-1504, 2023 02 22.
Article in English | MEDLINE | ID: covidwho-2235673

ABSTRACT

Despite intense scrutiny throughout the pandemic, development of efficacious drugs against SARS-CoV-2 spread remains hindered. Understanding the underlying mechanisms of viral infection is fundamental for developing novel treatments. While angiotensin converting enzyme 2 (ACE2) is accepted as the key entry receptor of the virus, other infection mechanisms exist. Dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin (DC-SIGN) and its counterpart DC-SIGN-related (DC-SIGNR, also known as L-SIGN) have been recognized as possessing functional roles in COVID-19 disease and binding to SARS-CoV-2 has been demonstrated previously with ensemble and qualitative techniques. Here we examine the thermodynamic and kinetic parameters of the ligand-receptor interaction between these C-type lectins and the SARS-CoV-2 S1 protein using force-distance curve-based AFM and biolayer interferometry. We evidence that the S1 receptor binding domain is likely involved in this bond formation. Further, we employed deglycosidases and examined a nonglycosylated S1 variant to confirm the significance of glycosylation in this interaction. We demonstrate that the high affinity interactions observed occur through a mechanism distinct from that of ACE2.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Angiotensin-Converting Enzyme 2/metabolism , Lectins, C-Type/metabolism , Ligands , Protein Binding
5.
International Journal of Laboratory Hematology ; 45(Supplement 1):169, 2023.
Article in English | EMBASE | ID: covidwho-2219005

ABSTRACT

Introduction: COVID-19 and post-COVID syndrome affect different organs and systems, including blood cells. Hematological disorders in the acute period of COVID-19 are described, however, changes in blood cells and erythropoiesis in the long term require study. The aim of this study was to analyze the morphology of erythrocytes in patients with a history of COVID-19. Method(s): The study included 18 patients who had COVID-19 six or more months ago (age 47-80 years). 9 individuals without diagnosed COVID-19 were selected as a control group (age 24-68 years). Complete blood count was performed on a 5-diff hematology analyzer and erythrocyte morphology was assessed using an atomic force microscope by a semi-contact method. Result(s): Analysis of erythrocyte parameters in postCOVID patients shows a tendency to change some parameters in comparison with the control (Me [Q25;Q75]): RBC 4,8 [4,6;5,2] x10E12/L vs 4,3 [4,1;4,6] x10E12/L (p=0,08), MCV 85,5 [83,3;89,5] fL vs 90,7 [88,7;91,5] fL (p=0,04), MCH 30,0 [29,0;30,3] pg vs 30,6 [29,6;31,9] pg (p=0,09), RDW-CV 13,9 [13,6;14,7] % vs 12,8 [12,6;13,1] % (p=0,003). In addition, the parameters and morphology of erythrocytes changed according to the atomic force microscope. In postCOVID there were a slightly larger maximum cell diameter and a lower minimum height compared with controls: 9,9 [9,5;10,5] mum vs 9,2 [9,1;9,6] mum and 0,4 [0,4;0,6] mum vs 0,6 [0,5;0,6] mum, respectively (p=0,08). In the postCOVID group, there were more erythrocytes with a changed shape - echinocytes, drop-shaped cells, spherocytes: 16 out of 18 versus 1 out of 9 in the control (p=0,0004) and drop-shaped cells were most observed. In addition, 18 patients with postCOVID had no central lumen in their erythrocytes, while only 4 controls lacked it (p=0,003). Conclusion(s): Thus, morphological changes in red blood cells are preserved in patients who have had covid-19 in the long-term period. At the same time, the data of the complete blood count are consistent with the results of an atomic force microscopy. (Figure Presented).

6.
Nano Lett ; 23(2): 619-628, 2023 01 25.
Article in English | MEDLINE | ID: covidwho-2185488

ABSTRACT

Anti-spike neutralizing antibodies (S NAbs) have been developed for prevention and treatment against COVID-19. The nanoscopic characterization of the dynamic interaction between spike proteins and S NAbs remains difficult. By using high-speed atomic force microscopy (HS-AFM), we elucidate the molecular property of an S NAb and its interaction with spike proteins. The S NAb appeared as monomers with a Y conformation at low density and formed hexameric oligomers at high density. The dynamic S NAb-spike protein interaction at RBD induces neither RBD opening nor S1 subunit shedding. Furthermore, the interaction was stable at endosomal pH. These findings indicated that the S NAb could have a negligible risk of antibody-dependent enhancement. Dynamic movement of spike proteins on small extracellular vesicles (S sEV) resembled that on SARS-CoV-2. The sensitivity of variant S sEVs to S NAb could be evaluated using HS-AFM. Altogether, we demonstrate a nanoscopic assessment platform for evaluating the binding property of S NAbs.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Antibodies, Viral , Antibodies, Neutralizing
7.
Cell Rep Med ; 3(10): 100774, 2022 10 18.
Article in English | MEDLINE | ID: covidwho-2050073

ABSTRACT

"Pan-coronavirus" antivirals targeting conserved viral components can be designed. Here, we show that the rationally engineered H84T-banana lectin (H84T-BanLec), which specifically recognizes high mannose found on viral proteins but seldom on healthy human cells, potently inhibits Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (including Omicron), and other human-pathogenic coronaviruses at nanomolar concentrations. H84T-BanLec protects against MERS-CoV and SARS-CoV-2 infection in vivo. Importantly, intranasally and intraperitoneally administered H84T-BanLec are comparably effective. Mechanistic assays show that H84T-BanLec targets virus entry. High-speed atomic force microscopy depicts real-time multimolecular associations of H84T-BanLec dimers with the SARS-CoV-2 spike trimer. Single-molecule force spectroscopy demonstrates binding of H84T-BanLec to multiple SARS-CoV-2 spike mannose sites with high affinity and that H84T-BanLec competes with SARS-CoV-2 spike for binding to cellular ACE2. Modeling experiments identify distinct high-mannose glycans in spike recognized by H84T-BanLec. The multiple H84T-BanLec binding sites on spike likely account for the drug compound's broad-spectrum antiviral activity and the lack of resistant mutants.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Humans , SARS-CoV-2 , Lectins/pharmacology , Mannose/pharmacology , Angiotensin-Converting Enzyme 2 , Spike Glycoprotein, Coronavirus/pharmacology , Antiviral Agents/pharmacology
8.
Lege Artis Medicinae ; 32(3):147-152, 2022.
Article in Hungarian | Scopus | ID: covidwho-1836550

ABSTRACT

The Covid-19 pandemic has swept across the world, causing a never seen burden on our health care systems and challenging biomedical research to give appropriate answers to the epidemic. Modern, one-particle biophysical methods ensure special insight to the characteristics of the cause of the epidemic, the SARS-CoV-2. The virus carries a crown-like layer of spike proteins, which plays a fundamental role in the process of infection. The topography structure and mechanical characteristics of native virions have been determined by atomic force microscopy. Spike proteins form a dynamic surface due to their flexibility and motility. Virions are surprisingly resistant to mechanical compression, and their structure is able to recover after mechanical perturbation. The global structure of the virus is resistant to heat effect, but spike proteins dissociate from the surface with higher temperatures. The mechanical and dynamic characteristics of SARS-CoV-2 contribute to its virulence. The applied one-particle biophysical methods play an important role in understanding and fighting with the more common virus infections. © 2022 Literatura Medica Publishing House. All rights reserved.

9.
Cells ; 11(8)2022 04 12.
Article in English | MEDLINE | ID: covidwho-1785542

ABSTRACT

Salvia miltiorrhiza Bunge, commonly called danshen, is widely used in traditional Chinese medicine for its cardiovascular and neuroprotective effects, which include antioxidative, anti-inflammatory, and antifibrotic properties. The purpose of this study was to evaluate the preclinical potential of S. miltiorrhiza extracts for the treatment of COVID-19. First, the impact of the extract on the binding between SARS-CoV-2 and the cellular ACE2 receptors was assessed using atomic force microscopy (AFM), showing a significant reduction in binding by the extract at concentrations in the µg/mL range. Second, the interference of this extract with the inflammatory response of blood mononuclear cells (PBMCs) was determined, demonstrating potent inhibitory properties in the same concentration range on pro-inflammatory cytokine release and interference with the activation of NFκB signaling. Together, these in vitro data demonstrate the potential of S. miltiorrhiza against COVID-19, consisting first of the blockade of the binding of SARS-CoV-2 to the ACE2 receptor and the mitigation of the inflammatory response from leukocytes by interfering with NFκB signaling. This dataset prompts the launch of a clinical trial to address in vivo the clinical benefits of this promising agent.


Subject(s)
COVID-19 Drug Treatment , Salvia miltiorrhiza , Angiotensin-Converting Enzyme 2 , Medicine, Chinese Traditional , NF-kappa B , SARS-CoV-2 , Salvia miltiorrhiza/chemistry
10.
Int J Mol Sci ; 23(6)2022 Mar 11.
Article in English | MEDLINE | ID: covidwho-1742489

ABSTRACT

The pandemic emergency determined by the spreading worldwide of the SARS-CoV-2 virus has focused the scientific and economic efforts of the pharmaceutical industry and governments on the possibility to fight the virus by genetic immunization. The genetic material must be delivered inside the cells by means of vectors. Due to the risk of adverse or immunogenic reaction or replication connected with the more efficient viral vectors, non-viral vectors are in many cases considered as a preferred strategy for gene delivery into eukaryotic cells. This paper is devoted to the evaluation of the gene delivery ability of new synthesized gemini bis-pyridinium surfactants with six methylene spacers, both hydrogenated and fluorinated, in comparison with compounds with spacers of different lengths, previously studied. Results from MTT proliferation assay, electrophoresis mobility shift assay (EMSA), transient transfection assay tests and atomic force microscopy (AFM) imaging confirm that pyridinium gemini surfactants could be a valuable tool for gene delivery purposes, but their performance is highly dependent on the spacer length and strictly related to their structure in solution. All the fluorinated compounds are unable to transfect RD-4 cells, if used alone, but they are all able to deliver a plasmid carrying an enhanced green fluorescent protein (EGFP) expression cassette, when co-formulated with 1,2-dioleyl-sn-glycero-3-phosphoethanolamine (DOPE) in a 1:2 ratio. The fluorinated compounds with spacers formed by six (FGP6) and eight carbon atoms (FGP8) give rise to a very interesting gene delivery activity, greater to that of the commercial reagent, when formulated with DOPE. The hydrogenated compound GP16_6 is unable to sufficiently compact the DNA, as shown by AFM images.


Subject(s)
DNA/genetics , Gene Transfer Techniques , Methane/chemistry , Pyridinium Compounds/chemistry , Surface-Active Agents/chemistry , Transfection/methods , A549 Cells , Cell Survival , DNA/chemistry , DNA/metabolism , Genetic Therapy/methods , Halogenation , Humans , Hydrogenation , Methane/metabolism , Microscopy, Atomic Force , Molecular Structure , Plasmids/chemistry , Plasmids/genetics , Plasmids/metabolism , Pyridinium Compounds/metabolism , Reproducibility of Results , Surface-Active Agents/metabolism
11.
Int J Mol Sci ; 23(4)2022 Feb 12.
Article in English | MEDLINE | ID: covidwho-1715397

ABSTRACT

The state of red blood cells (RBCs) and their functional possibilities depend on the structural organization of the membranes. Cell morphology and membrane nanostructure are compositionally and functionally related to the cytoskeleton network. In this work, the influence of agents (hemin, endogenous oxidation during storage of packed RBCs, ultraviolet (UV) radiation, temperature, and potential of hydrogen (pH) changes) on the relationships between cytoskeleton destruction, membrane nanostructure, and RBC morphology was observed by atomic force microscope. It was shown that the influence of factors of a physical and biochemical nature causes structural rearrangements in RBCs at all levels of organization, forming a unified mechanism of disturbances in relationships "cytoskeleton-membrane nanosurface-cell morphology". Filament ruptures and, consequently, large cytoskeleton pores appeared. The pores caused membrane topological defects in the form of separate grain domains. Increasing loading doses led to an increase in the number of large cytoskeleton pores and defects and their fusion at the membrane nanosurfaces. This caused the changes in RBC morphology. Our results can be used in molecular cell biology, membrane biophysics, and in fundamental and practical medicine.


Subject(s)
Cell Membrane/ultrastructure , Cytoskeleton/ultrastructure , Erythrocytes/pathology , Adult , Cells, Cultured , Erythrocytes/drug effects , Erythrocytes/radiation effects , Female , Hemin/toxicity , Humans , Hydrogen-Ion Concentration , Light/adverse effects , Male , Middle Aged , Oxidants/toxicity
12.
Viruses ; 13(11)2021 11 19.
Article in English | MEDLINE | ID: covidwho-1538549

ABSTRACT

A growing number of studies indicate that mRNAs and long ncRNAs can affect protein populations by assembling dynamic ribonucleoprotein (RNP) granules. These phase-separated molecular 'sponges', stabilized by quinary (transient and weak) interactions, control proteins involved in numerous biological functions. Retroviruses such as HIV-1 form by self-assembly when their genomic RNA (gRNA) traps Gag and GagPol polyprotein precursors. Infectivity requires extracellular budding of the particle followed by maturation, an ordered processing of ∼2400 Gag and ∼120 GagPol by the viral protease (PR). This leads to a condensed gRNA-NCp7 nucleocapsid and a CAp24-self-assembled capsid surrounding the RNP. The choreography by which all of these components dynamically interact during virus maturation is one of the missing milestones to fully depict the HIV life cycle. Here, we describe how HIV-1 has evolved a dynamic RNP granule with successive weak-strong-moderate quinary NC-gRNA networks during the sequential processing of the GagNC domain. We also reveal two palindromic RNA-binding triads on NC, KxxFxxQ and QxxFxxK, that provide quinary NC-gRNA interactions. Consequently, the nucleocapsid complex appears properly aggregated for capsid reassembly and reverse transcription, mandatory processes for viral infectivity. We show that PR is sequestered within this RNP and drives its maturation/condensation within minutes, this process being most effective at the end of budding. We anticipate such findings will stimulate further investigations of quinary interactions and emergent mechanisms in crowded environments throughout the wide and growing array of RNP granules.


Subject(s)
HIV Infections/virology , HIV-1 , Nucleocapsid Proteins/immunology , Viral Proteases/immunology , HIV-1/immunology , HIV-1/physiology , Humans , Virus Assembly
13.
Front Cell Infect Microbiol ; 11: 655501, 2021.
Article in English | MEDLINE | ID: covidwho-1308269

ABSTRACT

Microbes have an arsenal of virulence factors that contribute to their pathogenicity. A number of challenges remain to fully understand disease transmission, fitness landscape, antimicrobial resistance and host heterogeneity. A variety of tools have been used to address diverse aspects of pathogenicity, from molecular host-pathogen interactions to the mechanisms of disease acquisition and transmission. Current gaps in our knowledge include a more direct understanding of host-pathogen interactions, including signaling at interfaces, and direct phenotypic confirmation of pathogenicity. Correlative microscopy has been gaining traction to address the many challenges currently faced in biomedicine, in particular the combination of optical and atomic force microscopy (AFM). AFM, generates high-resolution surface topographical images, and quantifies mechanical properties at the pN scale under physiologically relevant conditions. When combined with optical microscopy, AFM probes pathogen surfaces and their physical and molecular interaction with host cells, while the various modes of optical microscopy view internal cellular responses of the pathogen and host. Here we review the most recent advances in our understanding of pathogens, recent applications of AFM to the field, how correlative AFM-optical microspectroscopy and microscopy have been used to illuminate pathogenicity and how these methods can reach their full potential for studying host-pathogen interactions.


Subject(s)
Host-Pathogen Interactions , Humans , Microscopy, Atomic Force
14.
Curr Opin Colloid Interface Sci ; 55: 101479, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1267633

ABSTRACT

We provide here a general view on the interactions of surfactants with viruses, with a particular emphasis on how such interactions can be controlled and employed for inhibiting the infectivity of enveloped viruses, including coronaviruses. The aim is to provide to interested scientists from different fields, including chemistry, physics, biochemistry, and medicine, an overview of the basic properties of surfactants and (corona)viruses, which are relevant to understanding the interactions between the two. Various types of interactions between surfactant and virus are important, and they act on different components of a virus such as the lipid envelope, membrane (envelope) proteins and nucleocapsid proteins. Accordingly, this cannot be a detailed account of all relevant aspects but instead a summary that bridges between the different disciplines. We describe concepts and cover a selection of the relevant literature as an incentive for diving deeper into the relevant material. Our focus is on more recent developments around the COVID-19 pandemic caused by SARS-CoV-2, applications of surfactants against the virus, and on the potential future use of surfactants for pandemic relief. We also cover the most important aspects of the historical development of using surfactants in combatting virus infections. We conclude that surfactants are already playing very important roles in various directions of defence against viruses, either directly, as in disinfection, or as carrier components of drug delivery systems for prophylaxis or treatment. By designing tailor-made surfactants, and consequently, advanced formulations, one can expect more and more effective use of surfactants, either directly as antiviral compounds or as part of more complex formulations.

15.
Sens Actuators B Chem ; 337: 129786, 2021 Jun 15.
Article in English | MEDLINE | ID: covidwho-1146819

ABSTRACT

The rapid and sensitive diagnosis of the highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the crucial issues at the outbreak of the ongoing global pandemic that has no valid cure. Here, we propose a SARS-CoV-2 antibody conjugated magnetic graphene quantum dots (GQDs)-based magnetic relaxation switch (MRSw) that specifically recognizes the SARS-CoV-2. The probe of MRSw can be directly mixed with the test sample in a fully sealed vial without sample pretreatment, which largely reduces the testers' risk of infection during the operation. The closed-tube one-step strategy to detect SARS-CoV-2 is developed with home-made ultra-low field nuclear magnetic resonance (ULF NMR) relaxometry working at 118 µT. The magnetic GQDs-based probe shows ultra-high sensitivity in the detection of SARS-CoV-2 due to its high magnetic relaxivity, and the limit of detection is optimized to 248 Particles mL‒1. Meanwhile, the detection time in ULF NMR system is only 2 min, which can significantly improve the efficiency of detection. In short, the magnetic GQDs-based MRSw coupled with ULF NMR can realize a rapid, safe, and sensitive detection of SARS-CoV-2.

16.
Nano Lett ; 21(6): 2675-2680, 2021 03 24.
Article in English | MEDLINE | ID: covidwho-1039625

ABSTRACT

SARS-CoV-2, the virus responsible for the current COVID-19 pandemic, displays a corona-shaped layer of spikes which play a fundamental role in the infection process. Recent structural data suggest that the spikes possess orientational freedom and the ribonucleoproteins segregate into basketlike structures. How these structural features regulate the dynamic and mechanical behavior of the native virion are yet unknown. By imaging and mechanically manipulating individual, native SARS-CoV-2 virions with atomic force microscopy, here, we show that their surface displays a dynamic brush owing to the flexibility and rapid motion of the spikes. The virions are highly compliant and able to recover from drastic mechanical perturbations. Their global structure is remarkably temperature resistant, but the virion surface becomes progressively denuded of spikes upon thermal exposure. The dynamics and the mechanics of SARS-CoV-2 are likely to affect its stability and interactions.


Subject(s)
COVID-19/virology , SARS-CoV-2/chemistry , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/physiology , Virion/chemistry , Virion/physiology , Biomechanical Phenomena , Hot Temperature , Humans , Microscopy, Atomic Force , Models, Molecular , Nanostructures/chemistry , Nanostructures/ultrastructure , Nanotechnology , Pandemics , Protein Conformation , Protein Stability , SARS-CoV-2/ultrastructure , Single Molecule Imaging , Spike Glycoprotein, Coronavirus/ultrastructure , Thermodynamics , Virion/ultrastructure
17.
Adv Nanobiomed Res ; 1(2): 2000024, 2021 Feb.
Article in English | MEDLINE | ID: covidwho-970069

ABSTRACT

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a serious threat to the health of millions of people. Respiratory viruses such as SARS-CoV-2 can be transmitted via airborne and fomite routes. The latter requires virion adsorption at abiotic surfaces and most likely involves the SARS-CoV-2 spike protein subunit 1 (S1), which is the outermost point of its envelope. Understanding S1 spike protein interaction with fomite surfaces thus represents an important milestone on the road to fighting the spread of COVID-19. Herein, high-speed atomic force microscopy (HS-AFM) is used to monitor the adsorption of the SARS-CoV-2 spike protein S1 at Al2O3(0001) and TiO2(100) surfaces in situ. While the single-crystalline oxide substrates are chosen to model the native surface oxides of Al- and Ti-based fomites, adsorption is studied in electrolytes that mimic the pH and major ionic components of mucosal secretions and saliva, respectively. Quantitative analysis of the obtained HS-AFM images indicates that S1 spike protein adsorption at these surfaces is mostly governed by electrostatic interactions with possible contributions from van der Waals interactions. It thus proceeds more rapidly at the TiO2(100) than at the Al2O3(0001) surface.

18.
Microsc Res Tech ; 83(12): 1623-1638, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-695947

ABSTRACT

Severe Acute Respiratory Syndrome Coronaviruses (SARS-CoVs), causative of major outbreaks in the past two decades, has claimed many lives all over the world. The virus effectively spreads through saliva aerosols or nasal discharge from an infected person. Currently, no specific vaccines or treatments exist for coronavirus; however, several attempts are being made to develop possible treatments. Hence, it is important to study the viral structure and life cycle to understand its functionality, activity, and infectious nature. Further, such studies can aid in the development of vaccinations against this virus. Microscopy plays an important role in examining the structure and topology of the virus as well as pathogenesis in infected host cells. This review deals with different microscopy techniques including electron microscopy, atomic force microscopy, fluorescence microscopy as well as computational methods to elucidate various prospects of this life-threatening virus.


Subject(s)
Computational Biology/methods , Coronavirus Infections/virology , Microscopy/methods , Severe acute respiratory syndrome-related coronavirus/pathogenicity , Severe acute respiratory syndrome-related coronavirus/ultrastructure , Animals , Chlorocebus aethiops , Host-Pathogen Interactions , Humans , Microscopy/classification , Microscopy, Atomic Force , Microscopy, Electron , Microscopy, Electron, Scanning , Microscopy, Fluorescence , Severe acute respiratory syndrome-related coronavirus/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Vero Cells
19.
ACS Nano ; 14(7): 7783-7807, 2020 07 28.
Article in English | MEDLINE | ID: covidwho-606642

ABSTRACT

Biosensors and nanoscale analytical tools have shown huge growth in literature in the past 20 years, with a large number of reports on the topic of 'ultrasensitive', 'cost-effective', and 'early detection' tools with a potential of 'mass-production' cited on the web of science. Yet none of these tools are commercially available in the market or practically viable for mass production and use in pandemic diseases such as coronavirus disease 2019 (COVID-19). In this context, we review the technological challenges and opportunities of current bio/chemical sensors and analytical tools by critically analyzing the bottlenecks which have hindered the implementation of advanced sensing technologies in pandemic diseases. We also describe in brief COVID-19 by comparing it with other pandemic strains such as that of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) for the identification of features that enable biosensing. Moreover, we discuss visualization and characterization tools that can potentially be used not only for sensing applications but also to assist in speeding up the drug discovery and vaccine development process. Furthermore, we discuss the emerging monitoring mechanism, namely wastewater-based epidemiology, for early warning of the outbreak, focusing on sensors for rapid and on-site analysis of SARS-CoV2 in sewage. To conclude, we provide holistic insights into challenges associated with the quick translation of sensing technologies, policies, ethical issues, technology adoption, and an overall outlook of the role of the sensing technologies in pandemics.


Subject(s)
Betacoronavirus/isolation & purification , Biosensing Techniques/methods , Coronavirus Infections/virology , Nanotechnology/methods , Pneumonia, Viral/virology , Betacoronavirus/pathogenicity , COVID-19 , Contact Tracing/methods , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Humans , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , SARS-CoV-2
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