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Visual quantitative point-of-care immunoassay based on signal transduction amplification and hue-recognition analysis
Lijiao Ao1, Daquan Li2, Sai Chu2
1Hangzhou Center for Disease Control and Prevention (Hangzhou Health Supervision Institute), Hangzhou, 310021, PR China; Shenzhen People's Hospital, Shenzhen, 518020, PR China; Zhejiang Key Laboratory of Multi-Omics in Infection and Immunity, Hangzhou, 310021, PR China.
This study presents a novel visual immunoassay for C-reactive protein (CRP) detection using quantum dots and smartphone imaging. The method offers accurate, equipment-independent point-of-care diagnosis with high sensitivity and specificity.
Area of Science:
- Biomedical Engineering
- Analytical Chemistry
- Nanotechnology
Background:
- Visual immunoassays offer equipment-independent biomarker detection for point-of-care applications.
- Current methods often rely on subjective interpretation or complex instrumentation.
- Developing sensitive and accurate visual detection strategies is crucial for accessible diagnostics.
Purpose of the Study:
- To develop a visual immunoassay for C-reactive protein (CRP) using a hue-recognition strategy.
- To achieve sensitive and accurate quantification of CRP using dual-emissive quantum dots and smartphone imaging.
- To enable equipment-independent, point-of-care diagnosis of CRP.
Main Methods:
- Utilized a ratiometric fluorescent probe with dual-emissive quantum dots (QDs) for a red-to-green hue gradient.
- Integrated a sandwich immunoassay on an ELISA plate with silver particle labels for signal amplification.
- Employed a hue-recognition strategy for visual analysis and smartphone imaging for quantification.
- Investigated the response of QDs to Ag+ ions released during the assay.
Main Results:
- Achieved vivid and sensitive color changes for CRP detection with high color fidelity and prominent hue variation.
- Enabled eye-perception of 5 specific CRP concentration points and 4 intervals with high reading accuracy (97.5% and 96.4%).
- Demonstrated a broad CRP responsive range (0-500 ng/mL) and a low limit of detection (0.062 ng/mL).
- Smartphone-based quantification showed high correlation with visual analysis.
Conclusions:
- The developed portable immunoassay provides a robust and accurate method for point-of-care CRP clinical diagnosis.
- The hue-recognition strategy offers superior performance compared to traditional lightness-gradient methods.
- This visual assay is equipment-independent, sensitive, specific, and suitable for home-testing scenarios.
- The integration of nanotechnology and smartphone imaging enhances diagnostic accessibility.
