Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 9 de 9
Filter
1.
Mikrochim Acta ; 188(10): 316, 2021 Sep 02.
Article in English | MEDLINE | ID: covidwho-1604245

ABSTRACT

A novel label-free surface plasmon resonance (SPR) aptasensor has been constructed for the detection of N-gene of SARS-CoV-2 by using thiol-modified niobium carbide MXene quantum dots (Nb2C-SH QDs) as the bioplatform for anchoring N-gene-targeted aptamer. In the presence of SARS-CoV-2 N-gene, the immobilized aptamer strands changed their conformation to specifically bind with N-gene. It thus increased the contact area or enlarged the distance between aptamer and the SPR chip, resulting in a change of the SPR signal irradiated by the laser (He-Ne) with the wavelength (λ) of 633 nm. Nb2C QDs were derived from Nb2C MXene nanosheets via a solvothermal method, followed by functionalization with octadecanethiol through a self-assembling method. Subsequently, the gold chip for SPR measurements was modified with Nb2C-SH QDs via covalent binding of the Au-S bond also by self-assembling interaction. Nb2C-SH QDs not only resulted in high bioaffinity toward aptamer but also enhanced the SPR response. Thus, the Nb2C-SH QD-based SPR aptasensor had low limit of detection (LOD) of 4.9 pg mL-1 toward N-gene within the concentration range 0.05 to 100 ng mL-1. The sensor also showed excellent selectivity in the presence of various respiratory viruses and proteins in human serum and high stability. Moreover, the Nb2C-SH QD-based SPR aptasensor displayed a vast practical application for the qualitative analysis of N-gene from different samples, including seawater, seafood, and human serum. Thus, this work can provide a deep insight into the construction of the aptasensor for detecting SARS-CoV-2 in complex environments. A novel label-free surface plasmon resonance aptasensor has been constructed to detect sensitively and selectively the N-gene of SARS-CoV-2 by using thiol-modified niobium carbide MXene quantum dots as the scaffold to anchor the N-gene-targeted aptamer.


Subject(s)
Aptamers, Nucleotide , COVID-19/diagnosis , Niobium/chemistry , Nucleocapsid/metabolism , Quantum Dots/chemistry , SARS-CoV-2/isolation & purification , Surface Plasmon Resonance/methods , COVID-19/virology , Humans , Limit of Detection
2.
ACS Appl Mater Interfaces ; 13(34): 40342-40353, 2021 Sep 01.
Article in English | MEDLINE | ID: covidwho-1366784

ABSTRACT

Sensitive point-of-care methods for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in clinical specimens are urgently needed to achieve rapid screening of viral infection. We developed a magnetic quantum dot-based dual-mode lateral flow immunoassay (LFIA) biosensor for the high-sensitivity simultaneous detection of SARS-CoV-2 spike (S) and nucleocapsid protein (NP) antigens, which is beneficial for improving the detection accuracy and efficiency of SARS-CoV-2 infection in the point-of-care testing area. A high-performance magnetic quantum dot with a triple-QD shell (MagTQD) nanotag was first fabricated and integrated into the LFIA system to provide superior fluorescence signals, enrichment ability, and detectability for S/NP antigen testing. Two detection modes were provided by the proposed MagTQD-LFIA. The direct mode was used for rapid screening or urgent detection of suspected samples within 10 min, and the enrichment mode was used for the highly sensitive and quantitative analysis of SARS-CoV-2 antigens in biological samples without the interference of the "hook effect." The simultaneous detection of SARS-CoV-2 S/NP antigens was conducted in one LFIA strip, and the detection limits for two antigens under direct and enrichment modes were 1 and 0.5 pg/mL, respectively. The MagTQD-LFIA showed high accuracy, specificity, and stability in saliva and nasal swab samples and is an efficient tool with flexibility to meet the testing requirements for SARS-CoV-2 antigens in various situations.


Subject(s)
Antigens, Viral/analysis , Biosensing Techniques/methods , Coronavirus Nucleocapsid Proteins/analysis , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/analysis , Antibodies, Immobilized/immunology , Antibodies, Monoclonal/immunology , Antigens, Viral/immunology , Coronavirus Nucleocapsid Proteins/immunology , Fluorescence , Fluorescent Dyes/chemistry , Humans , Immunoassay/methods , Limit of Detection , Magnetite Nanoparticles/chemistry , Nasopharynx/virology , Phosphoproteins/analysis , Phosphoproteins/immunology , Quantum Dots/chemistry , Saliva/virology , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus/immunology
3.
Int J Mol Sci ; 22(8)2021 Apr 14.
Article in English | MEDLINE | ID: covidwho-1299443

ABSTRACT

Photodegradation of the aqueous solutions of acetylsalicylic acid, in the absence (ASA) and the presence of excipients (ASE), is demonstrated by the photoluminescence (PL). A shift of the PL bands from 342 and 338 nm to 358 and 361-397 nm for ASA and ASE in solid state and as aqueous solutions was reported. By exposure of the solution of ASA 0.3 M to UV light, a decrease in the PL band intensity was highlighted. This behavior was revealed for ASA in the presence of phosphate buffer (PB) having the pH equal to 6.4, 7, and 8 or by the interaction with NaOH 0.3 M. A different behavior was reported in the case of ASE. In the presence of PB, an increase in the intensity of the PL band of ASE simultaneously with a change of the ratio between the intensities of the bands at 361-364 and 394-397 nm was highlighted. The differences between PL spectra of ASA and ASE have their origin in the presence of salicylic acid (SAL). The interaction of ASE with NaOH induces a shift of the PL band at 405-407 nm. Arguments for the reaction of ASA with NaOH are shown by Raman scattering and FTIR spectroscopy.


Subject(s)
Aspirin/chemistry , Photolysis/radiation effects , Solutions/radiation effects , Water/chemistry , Aspirin/radiation effects , Cadmium Compounds/chemistry , Luminescence , Quantum Dots/chemistry , Spectrum Analysis, Raman , Ultraviolet Rays/adverse effects
4.
Chem Commun (Camb) ; 57(51): 6229-6232, 2021 Jun 24.
Article in English | MEDLINE | ID: covidwho-1246405

ABSTRACT

Tracking the viral progression of SARS-CoV-2 in COVID-19 infected body tissues is an emerging need of the current pandemic. Imaging at near infrared second biological window (NIR-II) offers striking benefits over the other technologies to explore deep-tissue information. Here we design, synthesise and characterise a molecular probe that selectively targets the N-gene of SARS-CoV-2. Highly specific antisense oligonucleotides (ASOs) were conjugated to lead sulfide quantum dots using a UV-triggered thiol-ene click chemistry for the recognition of viral RNA. Our ex vivo imaging studies demonstrated that the probe exhibits aggregation induced NIR-II emission only in presence of SARS-CoV-2 RNA which can be attributed to the efficient hybridisation of the ASOs with their target RNA strands.


Subject(s)
COVID-19/diagnosis , COVID-19/virology , Fluorescent Dyes/chemistry , Oligonucleotides, Antisense/chemistry , Quantum Dots/chemistry , SARS-CoV-2/isolation & purification , Spectroscopy, Near-Infrared/methods , Animals , COVID-19/diagnostic imaging , COVID-19/metabolism , Click Chemistry/methods , Fluorescent Dyes/chemical synthesis , Humans , Lung/diagnostic imaging , Lung/metabolism , Lung/virology , Metal Nanoparticles/chemistry , Mice , Mice, Inbred BALB C , Models, Animal , SARS-CoV-2/genetics , SARS-CoV-2/metabolism
5.
J Nanobiotechnology ; 18(1): 130, 2020 Sep 10.
Article in English | MEDLINE | ID: covidwho-755216

ABSTRACT

Fast point-of-care (POC) diagnostics represent an unmet medical need and include applications such as lateral flow assays (LFAs) for the diagnosis of sepsis and consequences of cytokine storms and for the treatment of COVID-19 and other systemic, inflammatory events not caused by infection. Because of the complex pathophysiology of sepsis, multiple biomarkers must be analyzed to compensate for the low sensitivity and specificity of single biomarker targets. Conventional LFAs, such as gold nanoparticle dyed assays, are limited to approximately five targets-the maximum number of test lines on an assay. To increase the information obtainable from each test line, we combined green and red emitting quantum dots (QDs) as labels for C-reactive protein (CRP) and interleukin-6 (IL-6) antibodies in an optical duplex immunoassay. CdSe-QDs with sharp and tunable emission bands were used to simultaneously quantify CRP and IL-6 in a single test line, by using a single UV-light source and two suitable emission filters for readout through a widely available BioImager device. For image and data processing, a customized software tool, the MultiFlow-Shiny app was used to accelerate and simplify the readout process. The app software provides advanced tools for image processing, including assisted extraction of line intensities, advanced background correction and an easy workflow for creation and handling of experimental data in quantitative LFAs. The results generated with our MultiFlow-Shiny app were superior to those generated with the popular software ImageJ and resulted in lower detection limits. Our assay is applicable for detecting clinically relevant ranges of both target proteins and therefore may serve as a powerful tool for POC diagnosis of inflammation and infectious events.


Subject(s)
Biomarkers/analysis , C-Reactive Protein/analysis , Immunoassay/methods , Interleukin-6/analysis , Quantum Dots/chemistry , Sepsis/diagnosis , Antibodies/immunology , Betacoronavirus/isolation & purification , C-Reactive Protein/immunology , COVID-19 , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Humans , Interleukin-6/immunology , Limit of Detection , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Point-of-Care Systems , SARS-CoV-2 , Sepsis/metabolism , Software , Ultraviolet Rays
6.
Mater Sci Eng C Mater Biol Appl ; 112: 110924, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-1017020

ABSTRACT

Research on highly effective antiviral drugs is essential for preventing the spread of infections and reducing losses. Recently, many functional nanoparticles have been shown to possess remarkable antiviral ability, such as quantum dots, gold and silver nanoparticles, nanoclusters, carbon dots, graphene oxide, silicon materials, polymers and dendrimers. Despite their difference in antiviral mechanism and inhibition efficacy, these functional nanoparticles-based structures have unique features as potential antiviral candidates. In this topical review, we highlight the antiviral efficacy and mechanism of these nanoparticles. Specifically, we introduce various methods for analyzing the viricidal activity of functional nanoparticles and the latest advances in antiviral functional nanoparticles. Furthermore, we systematically describe the advantages and disadvantages of these functional nanoparticles in viricidal applications. Finally, we discuss the challenges and prospects of antiviral nanostructures. This topic review covers 132 papers and will enrich our knowledge about the antiviral efficacy and mechanism of various functional nanoparticles.


Subject(s)
Antiviral Agents/chemistry , Nanoparticles/chemistry , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , DNA Viruses/drug effects , DNA Viruses/physiology , Graphite/chemistry , Metal Nanoparticles/chemistry , Metal Nanoparticles/toxicity , Nanoparticles/therapeutic use , Nanoparticles/toxicity , Polymers/chemistry , Quantum Dots/chemistry , Quantum Dots/therapeutic use , Quantum Dots/toxicity , Zika Virus/drug effects , Zika Virus Infection/drug therapy , Zika Virus Infection/veterinary
7.
Anal Chem ; 92(23): 15542-15549, 2020 12 01.
Article in English | MEDLINE | ID: covidwho-933643

ABSTRACT

A rapid and accurate method for detection of virus (SARS-CoV-2)-specific antibodies is important to contain the 2019 coronavirus disease (COVID-19) outbreak, which is still urgently needed. Here, we develop a colorimetric-fluorescent dual-mode lateral flow immunoassay (LFIA) biosensor for rapid, sensitive, and simultaneous detection of SARS-CoV-2-specific IgM and IgG in human serum using spike (S) protein-conjugated SiO2@Au@QD nanobeads (NBs) as labels. The assay only needs 1 µL of the serum sample, can be completed within 15 min, and is 100 times more sensitive than the colloidal gold-based LFIA. Two detection modes of our biosensor are available: the colorimetric mode for rapid screening of the patients with suspected SARS-CoV-2 infection without any special instrument and the fluorescent mode for sensitive and quantitative analyses to determine the concentrations of specific IgM/IgG in human serum and detect the infection early and precisely. We validated the proposed method using 16 positive serum samples from patients with COVID-19 and 41 negative samples from patients with other viral respiratory infections. The results demonstrated that combined detection of virus-specific IgM and IgG via SiO2@Au@QD LFIA can identify 100% of patients with SARS-CoV-2 infection with 100% specificity.


Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , Immunoassay/methods , Immunoglobulin G/blood , Immunoglobulin M/blood , Quantum Dots/chemistry , SARS-CoV-2/immunology , COVID-19/virology , Gold/chemistry , Humans , Particle Size , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Sensitivity and Specificity , Silicon Dioxide/chemistry , Spike Glycoprotein, Coronavirus/chemistry
8.
ACS Nano ; 14(9): 12234-12247, 2020 09 22.
Article in English | MEDLINE | ID: covidwho-741668

ABSTRACT

The first step of SARS-CoV-2 infection is binding of the spike protein's receptor binding domain to the host cell's ACE2 receptor on the plasma membrane. Here, we have generated a versatile imaging probe using recombinant Spike receptor binding domain conjugated to fluorescent quantum dots (QDs). This probe is capable of engaging in energy transfer quenching with ACE2-conjugated gold nanoparticles to enable monitoring of the binding event in solution. Neutralizing antibodies and recombinant human ACE2 blocked quenching, demonstrating a specific binding interaction. In cells transfected with ACE2-GFP, we observed immediate binding of the probe on the cell surface followed by endocytosis. Neutralizing antibodies and ACE2-Fc fully prevented binding and endocytosis with low nanomolar potency. Importantly, we will be able to use this QD nanoparticle probe to identify and validate inhibitors of the SARS-CoV-2 Spike and ACE2 receptor binding in human cells. This work enables facile, rapid, and high-throughput cell-based screening of inhibitors for coronavirus Spike-mediated cell recognition and entry.


Subject(s)
Endocytosis , Metal Nanoparticles/chemistry , Peptidyl-Dipeptidase A/metabolism , Quantum Dots/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2 , Betacoronavirus/metabolism , COVID-19 , Coronavirus Infections/metabolism , Gold , Humans , Pandemics , Peptidyl-Dipeptidase A/physiology , Pneumonia, Viral/metabolism , Protein Binding , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Virion
9.
Biosens Bioelectron ; 166: 112436, 2020 Oct 15.
Article in English | MEDLINE | ID: covidwho-665846

ABSTRACT

Our recent experience of the COVID-19 pandemic has highlighted the importance of easy-to-use, quick, cheap, sensitive and selective detection of virus pathogens for the efficient monitoring and treatment of virus diseases. Early detection of viruses provides essential information about possible efficient and targeted treatments, prolongs the therapeutic window and hence reduces morbidity. Graphene is a lightweight, chemically stable and conductive material that can be successfully utilized for the detection of various virus strains. The sensitivity and selectivity of graphene can be enhanced by its functionalization or combination with other materials. Introducing suitable functional groups and/or counterparts in the hybrid structure enables tuning of the optical and electrical properties, which is particularly attractive for rapid and easy-to-use virus detection. In this review, we cover all the different types of graphene-based sensors available for virus detection, including, e.g., photoluminescence and colorimetric sensors, and surface plasmon resonance biosensors. Various strategies of electrochemical detection of viruses based on, e.g., DNA hybridization or antigen-antibody interactions, are also discussed. We summarize the current state-of-the-art applications of graphene-based systems for sensing a variety of viruses, e.g., SARS-CoV-2, influenza, dengue fever, hepatitis C virus, HIV, rotavirus and Zika virus. General principles, mechanisms of action, advantages and drawbacks are presented to provide useful information for the further development and construction of advanced virus biosensors. We highlight that the unique and tunable physicochemical properties of graphene-based nanomaterials make them ideal candidates for engineering and miniaturization of biosensors.


Subject(s)
Betacoronavirus/isolation & purification , Biosensing Techniques , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Graphite , Pneumonia, Viral/diagnosis , Viruses/isolation & purification , Antigen-Antibody Reactions , Betacoronavirus/genetics , Betacoronavirus/pathogenicity , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Biosensing Techniques/trends , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques/instrumentation , Clinical Laboratory Techniques/methods , Clinical Laboratory Techniques/statistics & numerical data , Colorimetry , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , DNA, Viral/analysis , DNA, Viral/genetics , Electrochemical Techniques , Equipment Design , Graphite/chemistry , Humans , Luminescence , Nanostructures/chemistry , Nucleic Acid Hybridization , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , Quantum Dots/chemistry , SARS-CoV-2 , Spectrum Analysis, Raman , Surface Plasmon Resonance , Virology/methods , Viruses/genetics , Viruses/pathogenicity
SELECTION OF CITATIONS
SEARCH DETAIL
...