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1.
J Nanobiotechnology ; 20(1): 6, 2022 Jan 04.
Article in English | MEDLINE | ID: covidwho-1608546

ABSTRACT

BACKGROUND: Gold nanoparticles (AuNPs) have been widely used in local surface plasmon resonance (LSPR) immunoassays for biomolecule sensing, which is primarily based on two conventional methods: absorption spectra analysis and colorimetry. The low figure of merit (FoM) of the LSPR and high-concentration AuNP requirement restrict their limit of detection (LOD), which is approximately ng to µg mL-1 in antibody detection if there is no other signal or analyte amplification. Improvements in sensitivity have been slow in recent for a long time, and pushing the boundary of the current LOD is a great challenge of current LSPR immunoassays in biosensing. RESULTS: In this work, we developed spectral image contrast-based flow digital nanoplasmon-metry (Flow DiNM) to push the LOD boundary. Comparing the scattering image brightness of AuNPs in two neighboring wavelength bands near the LSPR peak, the peak shift signal is strongly amplified and quickly detected. Introducing digital analysis, the Flow DiNM provides an ultrahigh signal-to-noise ratio and has a lower sample volume requirement. Compared to the conventional analog LSPR immunoassay, Flow DiNM for anti-BSA detection in pure samples has an LOD as low as 1 pg mL-1 within only a 15-min detection time and 500 µL sample volume. Antibody assays against spike proteins of SARS-CoV-2 in artificial saliva that contained various proteins were also conducted to validate the detection of Flow DiNM in complicated samples. Flow DiNM shows significant discrimination in detection with an LOD of 10 pg mL-1 and a broad dynamic detection range of five orders of magnitude. CONCLUSION: Together with the quick readout time and simple operation, this work clearly demonstrated the high sensitivity and selectivity of the developed Flow DiNM in rapid antibody detection. Spectral image contrast and digital analysis further provide a new generation of LSPR immunoassay with AuNPs.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , Surface Plasmon Resonance/methods , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19 Serological Testing/instrumentation , Equipment Design , Gold/chemistry , Humans , Immunoassay/instrumentation , Immunoassay/methods , Metal Nanoparticles/chemistry , SARS-CoV-2/immunology , Saliva/virology , Spike Glycoprotein, Coronavirus/immunology , Surface Plasmon Resonance/instrumentation
2.
ACS Appl Mater Interfaces ; 13(42): 49754-49761, 2021 Oct 27.
Article in English | MEDLINE | ID: covidwho-1475248

ABSTRACT

A reliable and sensitive detection approach for SARS-CoV 2 is essential for timely infection diagnosis and transmission prevention. Here, a two-dimensional (2D) metal-organic framework (MOF)-based photoelectrochemical (PEC) aptasensor with high sensitivity and stability for SARS-CoV 2 spike glycoprotein (S protein) detection was developed. The PEC aptasensor was constructed by a plasmon-enhanced photoactive material (namely, Au NPs/Yb-TCPP) with a specific DNA aptamer against S protein. The Au NPs/Yb-TCPP fabricated by in situ growth of Au NPs on the surface of 2D Yb-TCPP nanosheets showed a high electron-hole (e-h) separation efficiency due to the enhancement effect of plasmon, resulting in excellent photoelectric performance. The modified DNA aptamer on the surface of Au NPs/Yb-TCPP can bind with S protein with high selectivity, thus decreasing the photocurrent of the system due to the high steric hindrance and low conductivity of the S protein. The established PEC aptasensor demonstrated a highly sensitive detection for S protein with a linear response range of 0.5-8 µg/mL with a detection limit of 72 ng/mL. This work presented a promising way for the detection of SARS-CoV 2, which may conduce to the impetus of clinic diagnostics.


Subject(s)
Aptamers, Nucleotide/chemistry , Biosensing Techniques/methods , Metal-Organic Frameworks/chemistry , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/analysis , Base Sequence , Biosensing Techniques/instrumentation , COVID-19/diagnosis , DNA/chemistry , Electrochemical Techniques/instrumentation , Electrochemical Techniques/methods , Electrodes , Gold/chemistry , Gold/radiation effects , Humans , Immobilized Nucleic Acids/chemistry , Light , Limit of Detection , Metal Nanoparticles/chemistry , Metal Nanoparticles/radiation effects , Pharynx/virology , Photochemical Processes , Porphyrins/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Ytterbium/chemistry
3.
J Nanobiotechnology ; 19(1): 301, 2021 Oct 01.
Article in English | MEDLINE | ID: covidwho-1448238

ABSTRACT

BACKGROUND: In the past decades, different diseases and viruses, such as Ebola, MERS and COVID-19, impacted the human society and caused huge cost in different fields. With the increasing threat from the new or unknown diseases, the demand of rapid and sensitive assay method is more and more urgent. RESULTS: In this work, we developed a magneto-optical biochip based on the Cotton-Mouton effect of γ-Fe2O3@Au core/shell magnetic nanoparticles. We performed a proof-of-concept experiment for the detection of the spike glycoprotein S of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The assay was achieved by measuring the magneto-optical Cotton-Mouton effect of the biochip. This magneto-optical biochip can not only be used to detect SARS-CoV-2 but also can be easily modified for other diseases assay. CONCLUSION: The assay process is simple and the whole testing time takes only 50 min including 3 min for the CM rotation measurement. The detection limit of our method for the spike glycoprotein S of SARS-CoV-2 is estimated as low as 0.27 ng/mL (3.4 pM).


Subject(s)
Antibodies, Viral/immunology , COVID-19 Testing/methods , COVID-19/diagnosis , Magnetic Iron Oxide Nanoparticles/chemistry , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , COVID-19/virology , Ferric Compounds/chemistry , Gold/chemistry , Humans , Immunoassay , Limit of Detection , Proof of Concept Study , SARS-CoV-2/isolation & purification , Sensitivity and Specificity
4.
Nanotheranostics ; 5(4): 461-471, 2021.
Article in English | MEDLINE | ID: covidwho-1369901

ABSTRACT

The gold nanoclusters (Au NCs) are a special kind of gold nanomaterial containing several gold atoms. Because of their small size and large surface area, Au NCs possess macroscopic quantum tunneling and dielectric domain effects. Furthermore, Au NCs fluorescent materials have longer luminous time and better photobleaching resistance compared with other fluorescent materials. The synthetic process of traditional Au NCs is complicated. Traditional Au NCs are prepared mainly by using polyamide amine type dendrites, and sixteen alkyl trimethylamine bromide or sulfhydryl small molecule as stabilizers. They are consequently synthesized by the reduction of strong reducing agents such as sodium borohydride. Notably, these materials are toxic and environmental-unfriendly. Therefore, there is an urgent need to develop more effective methods for synthesizing Au NCs via a green approach. On the other hand, the self-assembly of protein gold cluster-based materials, and their biomedical applications have become research hotspots in this field. We have been working on the synthesis, assembly and application of protein conjugated gold clusters for a long time. In this review, the synthesis and assembly of protein-gold nanoclusters and their usage in cell imaging and other medical research are discussed.


Subject(s)
Fluorescent Dyes , Gold , Green Fluorescent Proteins , Metal Nanoparticles , Optical Imaging , Theranostic Nanomedicine , Fluorescent Dyes/chemistry , Fluorescent Dyes/therapeutic use , Gold/chemistry , Gold/therapeutic use , Green Fluorescent Proteins/chemistry , Green Fluorescent Proteins/therapeutic use , Humans , Metal Nanoparticles/chemistry , Metal Nanoparticles/therapeutic use
5.
Biosensors (Basel) ; 11(7)2021 Jul 14.
Article in English | MEDLINE | ID: covidwho-1323111

ABSTRACT

Enteroviruses are ubiquitous mammalian pathogens that can produce mild to life-threatening disease. We developed a multimodal, rapid, accurate and economical point-of-care biosensor that can detect nucleic acid sequences conserved amongst 96% of all known enteroviruses. The biosensor harnesses the physicochemical properties of gold nanoparticles and oligonucleotides to provide colourimetric, spectroscopic and lateral flow-based identification of an exclusive enteroviral nucleic acid sequence (23 bases), which was identified through in silico screening. Oligonucleotides were designed to demonstrate specific complementarity towards the target enteroviral nucleic acid to produce aggregated gold-oligonucleotide nanoconstructs. The conserved target enteroviral nucleic acid sequence (≥1 × 10-7 M, ≥1.4 × 10-14 g/mL) initiates gold-oligonucleotide nanoconstruct disaggregation and a signal transduction mechanism, producing a colourimetric and spectroscopic blueshift (544 nm (purple) > 524 nm (red)). Furthermore, lateral-flow assays that utilise gold-oligonucleotide nanoconstructs were unaffected by contaminating human genomic DNA, demonstrated rapid detection of conserved target enteroviral nucleic acid sequence (<60 s), and could be interpreted with a bespoke software and hardware electronic interface. We anticipate that our methodology will translate in silico screening of nucleic acid databases to a tangible enteroviral desktop detector, which could be readily translated to related organisms. This will pave the way forward in the clinical evaluation of disease and complement existing strategies to overcome antimicrobial resistance.


Subject(s)
Biosensing Techniques , Metal Nanoparticles , Nucleic Acids , Gold/chemistry , Humans , Metal Nanoparticles/chemistry , Nucleic Acid Hybridization , Oligonucleotides
6.
Int J Nanomedicine ; 16: 4739-4753, 2021.
Article in English | MEDLINE | ID: covidwho-1315916

ABSTRACT

Background: Serological tests detecting severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are widely used in seroprevalence studies and evaluating the efficacy of the vaccination program. Some of the widely used serological testing techniques are enzyme-linked immune-sorbent assay (ELISA), chemiluminescence immunoassay (CLIA), and lateral flow immunoassay (LFIA). However, these tests are plagued with low sensitivity or specificity, time-consuming, labor-intensive, and expensive. We developed a serological test implementing flow-through dot-blot assay (FT-DBA) for SARS-CoV-2 specific IgG detection, which provides enhanced sensitivity and specificity while being quick to perform and easy to use. Methods: SARS-CoV-2 antigens were immobilized on nitrocellulose membrane to capture human IgG, which was then detected with anti-human IgG conjugated gold nanoparticle (hIgG-AuNP). A total of 181 samples were analyzed in-house. Within which 35 were further evaluated in US FDA-approved CLIA Elecsys SARS-CoV-2 assay. The positive panel consisted of RT-qPCR positive samples from patients with both <14 days and >14 days from the onset of clinical symptoms. The negative panel contained samples collected from the pre-pandemic era dengue patients and healthy donors during the pandemic. Moreover, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FT-DBA were evaluated against RT-qPCR positive sera. However, the overall efficacies were assessed with sera that seroconverted against either nucleocapsid (NCP) or receptor-binding domain (RBD). Results: In-house ELISA selected a total of 81 true seropositive and 100 seronegative samples. The sensitivity of samples with <14 days using FT-DBA was 94.7%, increasing to 100% for samples >14 days. The overall detection sensitivity and specificity were 98.8% and 98%, respectively, whereas the overall PPV and NPV were 99.6% and 99%. Moreover, comparative analysis between in-house ELISA assays and FT-DBA revealed clinical agreement of Cohen's Kappa value of 0.944. The FT-DBA showed sensitivity and specificity of 100% when compared with commercial CLIA kits. Conclusion: The assay can confirm past SARS-CoV-2 infection with high accuracy within 2 minutes compared to commercial CLIA or in-house ELISA. It can help track SARS-CoV-2 disease progression, population screening, and vaccination response. The ease of use of the assay without requiring any instruments while being semi-quantitative provides the avenue of its implementation in remote areas around the globe, where conventional serodiagnosis is not feasible.


Subject(s)
Gold/chemistry , Immunoblotting/methods , Immunoglobulin G/analysis , Metal Nanoparticles/chemistry , Nucleocapsid/analysis , SARS-CoV-2/isolation & purification , Adult , Antibodies, Viral/blood , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Male , Predictive Value of Tests , SARS-CoV-2/immunology , Sensitivity and Specificity , Seroepidemiologic Studies
7.
Molecules ; 25(20)2020 Oct 13.
Article in English | MEDLINE | ID: covidwho-1305732

ABSTRACT

Nano-islands are entities (droplets or other shapes) that are formed by spontaneous dewetting (agglomeration, in the early literature) of thin and very thin metallic (especially gold) films on a substrate, done by post-deposition heating or by using other sources of energy. In addition to thermally generated nano-islands, more recently, nanoparticle films have also been dewetted, in order to form nano-islands. The localized surface plasmon resonance (LSPR) band of gold nano-islands was found to be sensitive to changes in the surrounding environment, making it a suitable platform for sensing and biosensing applications. In this review, we revisit the development of the concept of nano-island(s), the thermodynamics of dewetting of thin metal films, and the effect of the substrate on the morphology and optical properties of nano-islands. A special emphasis is made on nanoparticle films and their applications to biosensing, with ample examples from the authors' work.


Subject(s)
Gold/chemistry , Nanocomposites/chemistry , Point-of-Care Systems , Surface Plasmon Resonance/instrumentation , Animals , Biosensing Techniques/instrumentation , Growth Hormone/analysis , Humans , Lab-On-A-Chip Devices , Milk/chemistry , Nanotechnology/methods , Surface Plasmon Resonance/methods
8.
Biosensors (Basel) ; 11(7)2021 Jul 08.
Article in English | MEDLINE | ID: covidwho-1302156

ABSTRACT

Three techniques were compared for lowering the limit of detection (LOD) of the lateral flow immunoassay (LFIA) of the receptor-binding domain of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) based on the post-assay in situ enlargement of Au nanoparticles (Au NPs) on a test strip. Silver enhancement (growth of a silver layer over Au NPs-Au@Ag NPs) and gold enhancement (growth of a gold layer over Au NPs) techniques and the novel technique of galvanic replacement of Ag by Au in Au@Ag NPs causing the formation of Au@Ag-Au NPs were performed. All the enhancements were performed on-site after completion of the conventional LFIA and maintained equipment-free assay. The assays demonstrated lowering of LODs in the following rows: 488 pg/mL (conventional LFIA with Au NPs), 61 pg/mL (silver enhancement), 8 pg/mL (galvanic replacement), and 1 pg/mL (gold enhancement). Using gold enhancement as the optimal technique, the maximal dilution of inactivated SARS-CoV-2-containing samples increased 500 times. The developed LFIA provided highly sensitive and rapid (8 min) point-of-need testing.


Subject(s)
COVID-19/diagnosis , Gold/chemistry , SARS-CoV-2/isolation & purification , Silver/chemistry , Spike Glycoprotein, Coronavirus/analysis , Binding Sites , Early Diagnosis , Humans , Immunoassay , Limit of Detection , Metal Nanoparticles , Point-of-Care Testing , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
9.
Chem Commun (Camb) ; 57(56): 6871-6874, 2021 Jul 13.
Article in English | MEDLINE | ID: covidwho-1281748

ABSTRACT

The trans-cleavage activity of the target-activated CRISPR/Cas12a liberated an RNA crosslinker from a molecular transducer, which facilitated the assembly of gold nanoparticles. Integration of the molecular transducer with isothermal amplification and CRISPR/Cas12a resulted in visual detection of the N gene and E gene of SARS-CoV-2 in 45 min.


Subject(s)
COVID-19/diagnosis , CRISPR-Cas Systems , Genes, Viral/genetics , Gold/chemistry , Metal Nanoparticles/chemistry , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , SARS-CoV-2/genetics , COVID-19/virology , Colorimetry , Cross-Linking Reagents , RNA/chemistry
10.
Microbiol Immunol ; 64(1): 33-51, 2020 Jan.
Article in English | MEDLINE | ID: covidwho-1262996

ABSTRACT

The spike (S) protein of coronavirus, which binds to cellular receptors and mediates membrane fusion for cell entry, is a candidate vaccine target for blocking coronavirus infection. However, some animal studies have suggested that inadequate immunization against severe acute respiratory syndrome coronavirus (SARS-CoV) induces a lung eosinophilic immunopathology upon infection. The present study evaluated two kinds of vaccine adjuvants for use with recombinant S protein: gold nanoparticles (AuNPs), which are expected to function as both an antigen carrier and an adjuvant in immunization; and Toll-like receptor (TLR) agonists, which have previously been shown to be an effective adjuvant in an ultraviolet-inactivated SARS-CoV vaccine. All the mice immunized with more than 0.5 µg S protein without adjuvant escaped from SARS after infection with mouse-adapted SARS-CoV; however, eosinophilic infiltrations were observed in the lungs of almost all the immunized mice. The AuNP-adjuvanted protein induced a strong IgG response but failed to improve vaccine efficacy or to reduce eosinophilic infiltration because of highly allergic inflammatory responses. Whereas similar virus titers were observed in the control animals and the animals immunized with S protein with or without AuNPs, Type 1 interferon and pro-inflammatory responses were moderate in the mice treated with S protein with and without AuNPs. On the other hand, the TLR agonist-adjuvanted vaccine induced highly protective antibodies without eosinophilic infiltrations, as well as Th1/17 cytokine responses. The findings of this study will support the development of vaccines against severe pneumonia-associated coronaviruses.


Subject(s)
Adjuvants, Immunologic/pharmacology , Coronavirus Infections/prevention & control , Gold/chemistry , Immunoglobulin G/immunology , Lung/immunology , Metal Nanoparticles/chemistry , Severe Acute Respiratory Syndrome/prevention & control , Spike Glycoprotein, Coronavirus/immunology , Analysis of Variance , Animals , Antibodies, Viral/immunology , Chlorocebus aethiops , Coronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/virology , Cytokines/metabolism , Disease Models, Animal , Female , Immunization , Lung/pathology , Mice , Mice, Inbred BALB C , Recombinant Proteins/immunology , SARS Virus/immunology , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/virology , Spike Glycoprotein, Coronavirus/genetics , Toll-Like Receptors , Vaccination , Vaccines, Synthetic , Vero Cells , Viral Envelope Proteins/genetics , Viral Envelope Proteins/immunology , Viral Vaccines/immunology , Viral Vaccines/pharmacology , Viral Vaccines/therapeutic use
11.
Carbohydr Polym ; 268: 118259, 2021 Sep 15.
Article in English | MEDLINE | ID: covidwho-1242891

ABSTRACT

Nitrocellulose (NC) membrane can have value-added applications for lateral flow assay (LFA)-based diagnostic tools, which has great potential for the detection of pathogens, such as COVID-19, in different environments. However, poor sensitivity of the NC membrane based LFA limits its further application in many cases. Herein, we developed a facile method for LFA sensitivity enhancement, by incorporating two-sugar barrier into LFAs: one between the conjugation pad and the test line, and the other between the test line and the control line. ORF1ab nucleic acid of COVID-19 was used as the model target to demonstrate the concept on the HF120 membrane. Results show that at optimum conditions, the two sugar barrier LFAs have a detection limit of 0.5 nM, which is compared to that of 2.5 nM for the control LFA, achieving a 5-fold sensitivity increase. This low cost, easy-to-fabricate and easy-to-integrate LFA method may have potential applications in other cellulose paper-based platforms.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , Collodion/chemistry , RNA, Messenger/analysis , Sugars/chemistry , Viral Proteins/genetics , COVID-19 Nucleic Acid Testing/instrumentation , DNA/chemistry , DNA Probes/chemistry , Gold/chemistry , Limit of Detection , Metal Nanoparticles/chemistry , Polyproteins/genetics , SARS-CoV-2/chemistry , Sensitivity and Specificity
12.
Nat Protoc ; 16(6): 3141-3162, 2021 06.
Article in English | MEDLINE | ID: covidwho-1209962

ABSTRACT

The global pandemic of coronavirus disease 2019 (COVID-19) highlights the shortcomings of the current testing paradigm for viral disease diagnostics. Here, we report a stepwise protocol for an RNA-extraction-free nano-amplified colorimetric test for rapid and naked-eye molecular diagnosis of COVID-19. The test employs a unique dual-prong approach that integrates nucleic acid (NA) amplification and plasmonic sensing for point-of-care detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with a sample-to-assay response time of <1 h. The RNA-extraction-free nano-amplified colorimetric test utilizes plasmonic gold nanoparticles capped with antisense oligonucleotides (ASOs) as a colorimetric reporter to detect the amplified nucleic acid from the COVID-19 causative virus, SARS-CoV-2. The ASOs are specific for the SARS-CoV-2 N-gene, and binding of the ASOs to their target sequence results in the aggregation of the plasmonic gold nanoparticles. This highly specific agglomeration step leads to a change in the plasmonic response of the nanoparticles. Furthermore, when tested using clinical samples, the accuracy, sensitivity and specificity of the test were found to be >98.4%, >96.6% and 100%, respectively, with a detection limit of 10 copies/µL. The test can easily be adapted to diagnose other viral infections with a simple modification of the ASOs and primer sequences. It also provides a low-cost, rapid approach requiring minimal instrumentation that can be used as a screening tool for the diagnosis of COVID-19 at point-of-care settings in resource-poor situations. The colorimetric readout of the test can even be monitored using a handheld optical reader to obtain a quantitative response. Therefore, we anticipate that this protocol will be widely useful for the development of biosensors for the molecular diagnostics of COVID-19 and other infectious diseases.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Gold/chemistry , Metal Nanoparticles/chemistry , Oligonucleotides, Antisense/chemistry , RNA, Viral/analysis , SARS-CoV-2/isolation & purification , COVID-19/virology , COVID-19 Nucleic Acid Testing/instrumentation , Colorimetry/instrumentation , Colorimetry/methods , Humans , Limit of Detection , Oligonucleotides, Antisense/genetics , Point-of-Care Testing , RNA, Viral/genetics , SARS-CoV-2/genetics
13.
Sci Rep ; 11(1): 8692, 2021 04 22.
Article in English | MEDLINE | ID: covidwho-1199310

ABSTRACT

A metal nanoparticle composite, namely TPNT1, which contains Au-NP (1 ppm), Ag-NP (5 ppm), ZnO-NP (60 ppm) and ClO2 (42.5 ppm) in aqueous solution was prepared and characterized by spectroscopy, transmission electron microscopy, dynamic light scattering analysis and potentiometric titration. Based on the in vitro cell-based assay, TPNT1 inhibited six major clades of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with effective concentration within the range to be used as food additives. TPNT1 was shown to block viral entry by inhibiting the binding of SARS-CoV-2 spike proteins to the angiotensin-converting enzyme 2 (ACE2) receptor and to interfere with the syncytium formation. In addition, TPNT1 also effectively reduced the cytopathic effects induced by human (H1N1) and avian (H5N1) influenza viruses, including the wild-type and oseltamivir-resistant virus isolates. Together with previously demonstrated efficacy as antimicrobials, TPNT1 can block viral entry and inhibit or prevent viral infection to provide prophylactic effects against both SARS-CoV-2 and opportunistic infections.


Subject(s)
Gold/pharmacology , Influenza A Virus, H1N1 Subtype/physiology , Influenza A Virus, H5N1 Subtype/physiology , SARS-CoV-2/physiology , Silver/pharmacology , Zinc Oxide/pharmacology , Angiotensin-Converting Enzyme 2/metabolism , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Drug Resistance, Viral/drug effects , Food Additives/pharmacology , Gold/chemistry , HEK293 Cells , Humans , Influenza A Virus, H1N1 Subtype/drug effects , Influenza A Virus, H5N1 Subtype/drug effects , Metal Nanoparticles/chemistry , Nanocomposites/chemistry , Oseltamivir/pharmacology , Particle Size , Protein Binding/drug effects , SARS-CoV-2/drug effects , Silver/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Virus Internalization/drug effects , Zinc Oxide/chemistry
14.
J Inorg Biochem ; 219: 111454, 2021 06.
Article in English | MEDLINE | ID: covidwho-1157503

ABSTRACT

In recent years, some viruses have caused a grave crisis to global public health, especially the human coronavirus. A truly effective vaccine is therefore urgently needed. Vaccines should generally have two features: delivering antigens and modulating immunity. Adjuvants have an unshakable position in the battle against the virus. In addition to the perennial use of aluminium adjuvant, nanoparticles have become the developing adjuvant candidates due to their unique properties. Here we introduce several typical nanoparticles and their antivirus vaccine adjuvant applications. Finally, for the combating of the coronavirus, we propose several design points, hoping to provide ideas for the development of personalized vaccines and adjuvants and accelerate the clinical application of adjuvants.


Subject(s)
Adjuvants, Immunologic/chemistry , Adjuvants, Immunologic/pharmacology , Nanoparticles/chemistry , Viral Vaccines/immunology , Aluminum/chemistry , Antibodies, Neutralizing/drug effects , Antibodies, Neutralizing/immunology , COVID-19 Vaccines/immunology , COVID-19 Vaccines/pharmacology , Calcium Phosphates/chemistry , Chitosan/chemistry , Gold/chemistry , Humans , Nanoparticles/administration & dosage , Th1 Cells/drug effects , Th1 Cells/immunology , Th2 Cells/drug effects , Th2 Cells/immunology , Viral Vaccines/chemistry
15.
Biosensors (Basel) ; 11(3)2021 Mar 06.
Article in English | MEDLINE | ID: covidwho-1143457

ABSTRACT

Surface Plasmon Resonance (SPR) is widely used in biological and chemical sensing with fascinating properties. However, the application of SPR to detect trace targets is hampered by non-specific binding and poor signal. A variety of approaches for amplification have been explored to overcome this deficiency including DNA aptamers as versatile target detection tools. Hybridization chain reaction (HCR) is a high-efficiency enzyme-free DNA amplification method operated at room temperature, in which two stable species of DNA hairpins coexist in solution until the introduction of the initiator strand triggers a cascade of hybridization events. At an optimal salt condition, as the concentrations of H1 and H2 increased, the HCR signals were enhanced, leading to signal amplification reaching up to 6.5-fold of the detection measure at 30 min. This feature enables DNA to act as an amplifying transducer for biosensing applications to provide an enzyme-free alternative that can easily detect complex DNA sequences. Improvement of more diverse recognition events can be achieved by integrating HCR with a phase-sensitive SPR (pSPR)-tested aptamer stimulus. This work seeks to establish pSPR aptamer system for highly informative sensing by means of an amplification HCR. Thus, combining pSPR and HCR technologies provide an expandable platform for sensitive biosensing.


Subject(s)
Biosensing Techniques , Nucleic Acid Hybridization , Surface Plasmon Resonance , Aptamers, Nucleotide/chemistry , DNA/chemistry , Gold/chemistry , Limit of Detection , Nucleic Acid Amplification Techniques
17.
ACS Sens ; 6(3): 1086-1093, 2021 03 26.
Article in English | MEDLINE | ID: covidwho-1120724

ABSTRACT

The outbreak of COVID-19 caused a worldwide public health crisis. Large-scale population screening is an effective means to control the spread of COVID-19. Reverse transcription-polymerase chain reaction (RT-qPCR) and serology assays are the most available techniques for SARS-CoV-2 detection; however, they suffer from either less sensitivity and accuracy or low instrument accessibility for screening. To balance the sensitivity, specificity, and test availability, here, we developed enhanced colorimetry, which is termed as a magnetic pull-down-assisted colorimetric method based on the CRISPR/Cas12a system (M-CDC), for SARS-CoV-2 detection. By this method, SARS-CoV-2 RNA from synthetic sequences and cultured viruses can be detected by the naked eye based on gold nanoparticle (AuNP) probes, with a detection limit of 50 RNA copies per reaction. With CRISPR/Cas12a-assisted detection, SARS-CoV-2 can be specifically distinguished from other closely related viruses. M-CDC was further used to analyze 41 clinical samples, whose performance was 95.12%, consistent with that of an approved Clinical RT-qPCR Diagnosis kit. The developed M-CDC method is not dependent on sophisticated instruments, which makes it potentially valuable to be applied for SARS-CoV-2 screening under poor conditions.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , RNA, Viral/analysis , SARS-CoV-2/genetics , Bacterial Proteins , CRISPR-Associated Proteins , CRISPR-Cas Systems , Cell Line, Tumor , Colorimetry , DNA/chemistry , DNA Probes , Endodeoxyribonucleases , Gold/chemistry , Humans , Metal Nanoparticles/chemistry
18.
Nanomedicine ; 34: 102372, 2021 06.
Article in English | MEDLINE | ID: covidwho-1117330

ABSTRACT

The development of vaccines is a crucial response against the COVID-19 pandemic and innovative nanovaccines could increase the potential to address this remarkable challenge. In the present study a B cell epitope (S461-493) from the spike protein of SARS-CoV-2 was selected and its immunogenicity validated in sheep. This synthetic peptide was coupled to gold nanoparticles (AuNP) functionalized with SH-PEG-NH2 via glutaraldehyde-mediated coupling to obtain the AuNP-S461-493 candidate, which showed in s.c.-immunized mice a superior immunogenicity (IgG responses) when compared to soluble S461-493; and led to increased expression of relevant cytokines in splenocyte cultures. Interestingly, the response triggered by AuNP-S461-493 was similar in magnitude to that induced using a conventional strong adjuvant (Freund's adjuvant). This study provides a platform for the development of AuNP-based nanovaccines targeting specific SARS-CoV-2 epitopes.


Subject(s)
COVID-19 Vaccines , Epitopes, B-Lymphocyte , Gold , Immunogenicity, Vaccine , Metal Nanoparticles , Peptides , Spike Glycoprotein, Coronavirus , Animals , COVID-19 Vaccines/chemical synthesis , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , COVID-19 Vaccines/pharmacology , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Epitopes, B-Lymphocyte/pharmacology , Gold/chemistry , Gold/pharmacology , HEK293 Cells , Humans , Metal Nanoparticles/chemistry , Metal Nanoparticles/therapeutic use , Mice , Mice, Inbred BALB C , Peptides/chemical synthesis , Peptides/chemistry , Peptides/immunology , Peptides/pharmacology , Sheep , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/pharmacology
19.
J Phys Chem Lett ; 12(8): 2166-2171, 2021 Mar 04.
Article in English | MEDLINE | ID: covidwho-1101616

ABSTRACT

The ongoing outbreak of the coronavirus infection has killed more than 2 million people. Herein, we demonstrate that Rhodamine 6G (Rh-6G) dye conjugated DNA aptamer-attached gold nanostar (GNS)-based distance-dependent nanoparticle surface energy transfer (NSET) spectroscopy has the capability of rapid diagnosis of specific SARS-CoV-2 spike recombinant antigen or SARS-CoV-2 spike protein pseudotyped baculovirus within 10 min. Because Rh-6G-attached single-stand DNA aptamer wrapped the GNS, 99% dye fluorescence was quenched because of the NSET process. In the presence of spike antigen or virus, the fluorescence signal persists because of the aptamer-spike protein binding. Specifically, the limit of detection for the NSET assay has been determined to be 130 fg/mL for antigen and 8 particles/mL for virus. Finally, we have demonstrated that DNA aptamer-attached GNSs can stop virus infection by blocking the angiotensin-converting enzyme 2 (ACE2) receptor binding capability and destroying the lipid membrane of the virus.


Subject(s)
Antigens, Viral/analysis , Aptamers, Nucleotide/chemistry , Biosensing Techniques/methods , COVID-19/diagnosis , Gold/chemistry , Metal Nanoparticles/chemistry , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/analysis , Angiotensin-Converting Enzyme 2/metabolism , Antigens, Viral/metabolism , Aptamers, Nucleotide/metabolism , COVID-19 Testing/methods , Energy Transfer , Humans , Limit of Detection , Protein Binding , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/metabolism
20.
Anal Chim Acta ; 1154: 338330, 2021 Apr 15.
Article in English | MEDLINE | ID: covidwho-1086723

ABSTRACT

The recent outbreak of coronavirus disease 2019 (COVID-19) is highly infectious, which threatens human health and has received increasing attention. So far, there is no specific drug or vaccine for COVID-19. Therefore, it is urgent to establish a rapid and sensitive early diagnosis platform, which is of great significance for physical separation of infected persons after rapid diagnosis. Here, we propose a colorimetric/SERS/fluorescence triple-mode biosensor based on AuNPs for the fast selective detection of viral RNA in 40 min. AuNPs with average size of 17 nm were synthesized, and colorimetric, surface enhanced Raman scattering (SERS), and fluorescence signals of sensors are simultaneously detected based on their basic aggregation property and affinity energy to different bio-molecules. The sensor achieves a limit detection of femtomole level in all triple modes, which is 160 fM in absorbance mode, 259 fM in fluorescence mode, and 395 fM in SERS mode. The triple-mode signals of the sensor are verified with each other to make the experimental results more accurate, and the capacity to recognize single-base mismatch in each working mode minimizes the false negative/positive reading of SARS-CoV-2. The proposed sensing platform provides a new way for the fast, sensitive, and selective detection of COVID-19 and other diseases.


Subject(s)
Biosensing Techniques/methods , COVID-19/diagnosis , Metal Nanoparticles/chemistry , RNA, Viral/analysis , SARS-CoV-2/genetics , COVID-19/virology , Gold/chemistry , Humans , Limit of Detection , Particle Size , RNA, Viral/chemistry , SARS-CoV-2/isolation & purification , Spectrum Analysis, Raman , Spike Glycoprotein, Coronavirus/genetics
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