Method and apparatus using selected superparamagnetic labels for rapid quantification of immunochromatographic tests

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Immunotechnology

Background:

• Immunochromatographic tests (ICTs) are widely used for point-of-care diagnostics.
• Quantification of ICT results often requires complex instrumentation or subjective interpretation.
• There is a need for rapid, sensitive, and objective methods for ICT analyte quantification.

Purpose of the Study:

• To develop and validate a novel, rapid method for quantifying analytes in ICTs.
• To demonstrate the method's efficacy using human chorionic gonadotropin (hCG) as a model analyte.
• To assess the method's sensitivity, linear range, and speed for clinical applications.

Main Methods:

• A sandwich assay format utilizing monoclonal antibodies against hCG.
• One antibody was conjugated to superparamagnetic particles; the other was immobilized on a porous membrane.
• Analyte quantification was achieved by measuring the magnetic signal of captured immune complexes.

Main Results:

• The method demonstrated a practical detection limit of 20 U/l (54 nM) for hCG in human urine.
• A wide linear range spanning three orders of magnitude (20 U/l to 10,000 U/l) was achieved.
• Assay completion time was under 10 minutes, indicating high throughput potential.

Conclusions:

• The developed method offers a fast and sensitive approach for quantifying ICTs.
• This technology is suitable for the rapid detection and monitoring of various clinically significant analytes.
• The magnetic detection principle provides an objective and automatable alternative for ICT analysis.