Laser-induced fluorescence reader with a turbidimetric system for sandwich-type immunoassay using nanoparticles

Area of Science:

• Analytical Chemistry
• Nanotechnology
• Biomedical Engineering

Background:

• Traditional immunoassays can suffer from experimental errors due to particle issues.
• Improving analytical performance requires advanced detection systems.
• Nanoparticles offer unique properties for assay development.

Purpose of the Study:

• To develop a novel laser-induced fluorescence (LIF) reader with an integrated turbidimetric system.
• To enhance the analytical performance of nanoparticle-based sandwich immunoassays.
• To reduce experimental errors associated with nanoparticle behavior in assays.

Main Methods:

• Developed a unique LIF reader incorporating a turbidimetric system.
• Synthesized magnetic nanoparticles (MNPs) for extraction and FITC-doped silica nanoparticles for fluorescence tagging.
• Utilized a sandwich-type immunoassay format for salinomycin detection.

Main Results:

• Achieved a detection limit of approximately 39 pg mL(-1) for salinomycin, a 2-fold improvement.
• Enhanced calibration linearity, with R(2)-coefficient increasing from 0.8601 to 0.9905.
• Improved assay sensitivity by 1.92-fold, indicated by an increased curve slope.
• Demonstrated reduced experimental error from particle loss, aggregation, and sinking.

Conclusions:

• The developed LIF reader with turbidimetry significantly improves nanoparticle-based immunoassay performance.
• The ratiometric measurement approach enhances accuracy and sensitivity.
• This system shows potential for fluorescence measurements with various nanomaterials, including quantum dots.