Regulation of probe density on upconversion nanoparticles enabling high-performance lateral flow assays

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Upconversion nanoparticles (UCNPs) offer high photostability and background-free fluorescence, making them promising for point-of-care testing (POCT).
• Existing UCNP probes require further optimization to improve detection sensitivity and broaden the analytical range for POCT applications.

Purpose of the Study:

• To optimize UCNP-based probes by regulating probe density for enhanced POCT performance.
• To validate the optimized UCNP probes using a lateral flow assay (LFA) for C-reactive protein (CRP) detection.

Main Methods:

• Optimization of UCNP probe density.
• Development of an optimized UCNP-LFA platform integrated with a custom fluorescence analyzer.
• Validation using C-reactive protein (CRP) as a model analyte.

Main Results:

• Achieved a nearly 20-fold increase in sensitivity for CRP detection.
• Established a limit of detection (LOD) of 0.046 ng/mL for CRP.
• Demonstrated a broad detection range of 0.2–300 ng/mL for CRP.
• Clinical validation showed results consistent with traditional clinical tests in serum samples.

Conclusions:

• Regulating probe density is an effective strategy for optimizing UCNP-based probes for high-performance POCT.
• The optimized UCNP-LFA platform demonstrates clinical practicability and potential for sensitive biomarker detection.
• This optimization approach is applicable to other nanoparticle-based bio-probes for expanding POCT capabilities.