Spectral-optical-tweezer-assisted fluorescence multiplexing system for QDs-encoded bead-array bioassay.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Optical Physics

Background:

• Bead-array technology enables separation-free multiplexed detection of biomolecules, ideal for scarce samples.
• Accurate analysis of biomolecules like antigens and antibodies is crucial for diagnostics.

Purpose of the Study:

• To develop and validate a spectral-optical-tweezer-assisted fluorescence multiplexing system for analyzing biomolecule-conjugated bead-arrays.
• To demonstrate the system's capability for both qualitative and quantitative detection of various targets.

Main Methods:

• Utilized optical tweezers to trap and stabilize beads for optimized fluorescence excitation and emission collection.
• Employed a spectrometer to record fluorescence emission spectra from quantum dot (QD)-encoded bead-arrays.
• Analyzed spectral data by recognizing decoding peaks and quantifying label signal intensities.

Main Results:

• Achieved multiplexed detection of anti-IgG antibodies with a detection limit of 1.52 fM and a linear range of 0.31–10 nM.
• Demonstrated specific IgG detection in human serum using a sandwich assay, reaching a detection limit of 0.23 fM and a linear range of 0.88–28 fM.

Conclusions:

• The spectral-optical-tweezer system provides a stable and optimized platform for sensitive, multiplexed biomolecule detection.
• The validated performance in real samples highlights the system's potential for practical diagnostic applications.