High-sensitivity lateral flow immunoassay with a fluorescent lanthanide nanoparticle label

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Lateral flow (LF) immunoassays are widely used for point-of-care testing, often employing visually read reporters like gold particles.
• Improving the sensitivity and quantitation of LF immunoassays necessitates the use of instrument-read reporters, such as fluorescent nanoparticles.

Purpose of the Study:

• To develop a quantitative, high-sensitivity LF immunoassay for free prostate specific antigen (fPSA) using fluorescent europium(III) chelate doped nanoparticle (Eu-np) reporters.
• To optimize assay parameters including dynamic range, duration, and step count to minimize detection limits.

Main Methods:

• Development of a quantitative LF immunoassay utilizing Eu-np reporters for fPSA detection.
• Systematic testing of simplified assay formats and modifiable parameters to enhance sensitivity.
• Comparison of molar detection limits with existing LF immunoassay reporters (gold, carbon nanoparticles).
• Determination of assay cutoff using female serum samples.

Main Results:

• The optimized fPSA assay achieved a detection limit of 0.01 ng/ml when fPSA was spiked into pooled female serum.
• This detection limit is approximately 100-fold lower than gold particle-based LF assays and 10-fold lower than other nanoparticle-based LF assays.
• Eu-np reporters demonstrated superior performance for developing sensitive and quantitative LF immunoassays.

Conclusions:

• Europium(III) chelate doped nanoparticles are effective reporters for developing highly sensitive and quantitative lateral flow immunoassays.
• This technology offers a significant improvement over traditional gold particle reporters for fPSA detection.
• The developed assay format holds promise for advanced point-of-care diagnostic applications.