Sensitive and rapid quantification of C-reactive protein using quantum dot-labeled microplate immunoassay

Area of Science:

• Biomarker detection
• Immunodiagnostics
• Quantum dot technology

Background:

• High-sensitivity C-reactive protein (hs-CRP) is crucial for predicting coronary heart disease (CHD) risk.
• Current hs-CRP assays often lack throughput, require complex procedures, or are unsuitable for resource-limited settings.

Purpose of the Study:

• To develop a novel, rapid, sensitive, and high-throughput hs-CRP assay.
• To address the limitations of existing hs-CRP detection methods, particularly in rural or resource-limited environments.

Main Methods:

• A quantum dot-labeled immunoassay was developed using a 96-well microplate format for simultaneous quantification of over 90 samples.
• A sandwich assay format utilizing two monoclonal antibodies (mAbs) targeting distinct hs-CRP epitopes was employed.
• Fluorescence intensity of the captured mAb-Ag-mAb complex was measured using a microplate reader.

Main Results:

• The assay demonstrated a wide analytical range (0.001-100 mg/L) and a low detection limit (0.06 μg/L) within 1.5 hours.
• High accuracy was confirmed with low intra-assay (2.27%) and inter-assay (8.52%) coefficients of variation and recoveries (96.7-104.2%).
• Bland-Altman analysis showed good consistency with commercial ELISA and nephelometry for 104 clinical samples.

Conclusions:

• The developed hs-CRP assay provides a rapid, sensitive, and high-throughput solution using minimal resources.
• The assay's versatility allows for the detection of other biomarkers by immobilizing specific monoclonal antibodies.