Development of Replication Protein A‑Conjugated Gold Nanoparticles for Highly Sensitive Detection of Disease Biomarkers

Paper-based lateral flow immunoassays (LFIAs) using conventional sandwich-type immunoassays are one of the most commonly used point-of-care (PoC) tests. However, the application of gold nanoparticles (AuNPs) in LFIAs does not meet sensitivity requirements for the detection of infectious diseases or...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2019-08, Vol.91 (15), p.10001-10007
Main Authors: Kang, Juyoung, Yeom, Gyuho, Jang, Hyungjun, Oh, Jusung, Park, Chin-Ju, Kim, Min-Gon
Format: Article
Language:English
Subjects:
Antibodies
Aptamers
Biomarkers
Body fluids
Calcium-binding protein
Chemistry
Gold
Immunoassay
Immunoassays
Infectious diseases
Influenza
Low concentrations
Nanoparticles
Protein A
Proteins
Replication
Replication protein A
Sensitivity
Single-stranded DNA
Target detection
Troponin
Troponin I
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Summary:Paper-based lateral flow immunoassays (LFIAs) using conventional sandwich-type immunoassays are one of the most commonly used point-of-care (PoC) tests. However, the application of gold nanoparticles (AuNPs) in LFIAs does not meet sensitivity requirements for the detection of infectious diseases or biomarkers present at low concentrations in body fluids because of the limited number of AuNPs that can bind to the target. To overcome this problem, we first developed a single-stranded DNA binding protein (RPA70A, DNA binding domain A of human Replication Protein A 70 kDa) conjugated to AuNPs for a sandwich assay using a capture antibody immobilized in the LFIA and an aptamer as a detection probe, thus, enabling signal intensity enhancement by attaching several AuNPs per aptamer. We applied this method to detect the influenza nucleoprotein (NP) and cardiac troponin I (cTnI). We visually detected spiked targets at a low femtomolar range, with limits of detection for NP in human nasal fluid and for cTnI in serum of 0.26 and 0.23 pg·mL–1, respectively. This technique showed significantly higher sensitivity than conventional methods that are widely used in LFIAs involving antibody-conjugated AuNPs. These results suggest that the proposed method can be universally applied to the detection of substances requiring high sensitivity and can be used in the field of PoC testing for early disease diagnosis.
ISSN:0003-2700
1520-6882
DOI:10.1021/acs.analchem.9b01827