scholarly journals Comparative Study of In Situ Techniques to Enlarge Gold Nanoparticles for Highly Sensitive Lateral Flow Immunoassay of SARS-CoV-2

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 229
Author(s):  
Vasily G. Panferov ◽  
Nadezhda A. Byzova ◽  
Sergey F. Biketov ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Limit Of Detection ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Silver Layer ◽  
Galvanic Replacement ◽  
Silver Enhancement ◽  
Ag Nps ◽  
Au Nps ◽  
Highly Sensitive

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.

scholarly journals Peroxidase-Mimicking Nanozyme with Surface-Dispersed Pt Atoms as the Label for the Lateral Flow Immunoassay of C-Reactive Protein

2021 ◽  
Author(s):  
Vasily Panferov ◽  
Nadezhda A. Byzova ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Limit Of Detection ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Silver Layer ◽  
Galvanic Replacement ◽  
C Reactive Protein ◽  
Ag Nps ◽  
Au Nps ◽  
New Approach ◽  
Reactive Protein

We report a new approach to synthesize nanozyme with low consumption of precious Pt-precursor and high peroxidase-mimicking activity. The synthesis includes the formation of gold nanoparticles (Au NPs), the overgrowth of a silver layer over Au NPs (Au@Ag NPs), and the galvanic replacement of Ag with PtCl<sub>6</sub><sup>2-</sup> leading to the formation of Au@Ag–Pt NPs with uniformly deposited catalytic Pt sites. The reported approach facilitates up to 20-times lower consumption of Pt precursor. The use of Au@Ag-Pt NPs as the catalytic label in lateral flow immunoassay results in a 65-fold lower limit of detection (15 pg/mL in serum).

scholarly journals Peroxidase-Mimicking Nanozyme with Surface-Dispersed Pt Atoms as the Label for the Lateral Flow Immunoassay of C-Reactive Protein

2021 ◽  
Author(s):  
Vasily Panferov ◽  
Nadezhda A. Byzova ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Limit Of Detection ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Silver Layer ◽  
Galvanic Replacement ◽  
C Reactive Protein ◽  
Ag Nps ◽  
Au Nps ◽  
New Approach ◽  
Reactive Protein

We report a new approach to synthesize nanozyme with low consumption of precious Pt-precursor and high peroxidase-mimicking activity. The synthesis includes the formation of gold nanoparticles (Au NPs), the overgrowth of a silver layer over Au NPs (Au@Ag NPs), and the galvanic replacement of Ag with PtCl<sub>6</sub><sup>2-</sup> leading to the formation of Au@Ag–Pt NPs with uniformly deposited catalytic Pt sites. The reported approach facilitates up to 20-times lower consumption of Pt precursor. The use of Au@Ag-Pt NPs as the catalytic label in lateral flow immunoassay results in a 65-fold lower limit of detection (15 pg/mL in serum).

scholarly journals Multi-Quantum Dots-Embedded Silica-Encapsulated Nanoparticle-Based Lateral Flow Assay for Highly Sensitive Exosome Detection

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 768
Author(s):  
Hyung-Mo Kim ◽  
Chiwoo Oh ◽  
Jaehyun An ◽  
Seungki Baek ◽  
Sungje Bock ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Limit Of Detection ◽  
Specific Binding ◽  
Calf Serum ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Uniform Size ◽  
Highly Sensitive ◽  
Wide Range ◽  
New Biomarkers

Exosomes are attracting attention as new biomarkers for monitoring the diagnosis and prognosis of certain diseases. Colorimetric-based lateral-flow assays have been previously used to detect exosomes, but these have the disadvantage of a high limit of detection. Here, we introduce a new technique to improve exosome detection. In our approach, highly bright multi-quantum dots embedded in silica-encapsulated nanoparticles (M–QD–SNs), which have uniform size and are brighter than single quantum dots, were applied to the lateral flow immunoassay method to sensitively detect exosomes. Anti-CD63 antibodies were introduced on the surface of the M–QD–SNs, and a lateral flow immunoassay with the M–QD–SNs was conducted to detect human foreskin fibroblast (HFF) exosomes. Exosome samples included a wide range of concentrations from 100 to 1000 exosomes/µL, and the detection limit of our newly designed system was 117.94 exosome/μL, which was 11 times lower than the previously reported limits. Additionally, exosomes were selectively detected relative to the negative controls, liposomes, and newborn calf serum, confirming that this method prevented non-specific binding. Thus, our study demonstrates that highly sensitive and quantitative exosome detection can be conducted quickly and accurately by using lateral immunochromatographic analysis with M–QD–SNs.

scholarly journals The Steadfast Au@Pt Soldier: Peroxide-Tolerant Nanozyme for Signal Enhancement in Lateral Flow Immunoassay of Peroxidase-Containing Samples

2020 ◽  
Author(s):  
Vasily Panferov ◽  
Irina V. Safenkova ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Hydrogen Peroxide ◽  
Potato Virus ◽  
Limit Of Detection ◽  
Potato Virus X ◽  
Fundamental Principle ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

<div>The approach to inhibit endogenous peroxidases by elevated concentrations of hydrogen peroxide while maintaining the high peroxidase-mimicking activity of Au@Pt nanozymes was developed. The approach facilitates selective and highly-sensitive detection of peroxidase-mimicking nanozyme nanozymes in the background of endogenous peroxidases. Au@Pt nanozyme was used as the colorimetric and catalytic label in lateral flow immunoassay of an important plant pathogen – potato virus X. The inhibition of endogenous peroxidases in plant extracts and selective detection of Au@Pt nanozyme provides the lowest limit of detection among immunochemical assays of potato virus X (up to 500 times lower compared to the assay with conventional gold nanoparticles). </div><div>The proposed approach uses the fundamental principle of enzyme inhibition by the substrate. It is universal and applicable to all matrixes with peroxidase activity. </div>

scholarly journals The Steadfast Au@Pt Soldier: Peroxide-Tolerant Nanozyme for Signal Enhancement in Lateral Flow Immunoassay of Peroxidase-Containing Samples

2020 ◽  
Author(s):  
Vasily Panferov ◽  
Irina V. Safenkova ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Hydrogen Peroxide ◽  
Potato Virus ◽  
Limit Of Detection ◽  
Potato Virus X ◽  
Fundamental Principle ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

<div>The approach to inhibit endogenous peroxidases by elevated concentrations of hydrogen peroxide while maintaining the high peroxidase-mimicking activity of Au@Pt nanozymes was developed. The approach facilitates selective and highly-sensitive detection of peroxidase-mimicking nanozyme nanozymes in the background of endogenous peroxidases. Au@Pt nanozyme was used as the colorimetric and catalytic label in lateral flow immunoassay of an important plant pathogen – potato virus X. The inhibition of endogenous peroxidases in plant extracts and selective detection of Au@Pt nanozyme provides the lowest limit of detection among immunochemical assays of potato virus X (up to 500 times lower compared to the assay with conventional gold nanoparticles). </div><div>The proposed approach uses the fundamental principle of enzyme inhibition by the substrate. It is universal and applicable to all matrixes with peroxidase activity. </div>

HIGHLY SENSITIVE IMMUNOASSAY WITH PEROXIDASE-MIMICKING NANOPARTICLES

2021 ◽  
Vol 1 (19) ◽  
pp. 279-280
Author(s):  
I.V. Safenkova ◽  
A.V. Zherdev ◽  
B.B. Dzantiev
Keyword(s):  
Catalytic Properties ◽  
Limit Of Detection ◽  
Pt Nanoparticles ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Inflammatory Biomarker ◽  
Highly Sensitive

Bi (Au@Ag)-and trimetallic (Au@Ag-Pt) nanoparticles with peroxidase-mimicking activity were synthesized. The nanoparticles were used for lateral flow immunoassay of phytopathogens and inflammatory biomarker. Low values of the limit of detection were achieved thanks to the unique optical and catalytic properties of the nanoparticles.

Highly sensitive multiplex lateral flow immunoassay of phytopathogens using Au@Pt nanoparticles as the colorimetric and catalytic label

2021 ◽  
Author(s):  
Vasily G. Panferov ◽  
Shyatesa C. Razo ◽  
Irina V. Safenkova ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Pt Nanoparticles ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Highly Sensitive

Au-on-Ag nanostructure for in-situ SERS monitoring of catalytic reactions

2022 ◽  
Author(s):  
Shuyue He ◽  
Di Wu ◽  
Siwei Chen ◽  
Kai Liu ◽  
Eui-Hyeok Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Thermal Evaporation ◽  
Reduction Process ◽  
Ag Nps ◽  
Au Nps ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Raman Probe

Abstract Dual-functionality Au-on-Ag nanostructures (AOA) were fabricated on a silicon substrate by first immobilizing citrate-reduced Ag nanoparticles (Ag NPs, ~43 nm in diameter), followed by depositing ~7 nm Au nanofilms (Au NFs) via thermal evaporation. Au NFs were introduced for their catalytic activity in concave-convex nano-configuration. Ag NPs underneath were used for their significant enhancement factor (EF) in surface-enhanced Raman scattering (SERS)-based measurements of analytes of interest. Rhodamine 6G (R6G) was utilized as the Raman-probe to evaluate the SERS sensitivity of AOA. The SERS EF of AOA is ~37 times than that of Au NPs. Using reduction of 4-nitrothiophenol (4-NTP) by sodium borohydride (NaBH4) as a model reaction, we demonstrated the robust catalytic activity of AOA as well as its capacity to continuously monitor via SERS the disappearance of reactant 4-NTP, emergence and disappearance of intermediate 4, 4’-DMAB, and the appearance of product 4-ATP throughout the reduction process in real-time and in situ.

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