A High-Sensitive Photothermal-Readout Strategy for Commercial Lateral Flow Immunoassays with an Optical Microfiber...

Area of Science:

• Biosensing
• Nanotechnology
• Optical Physics

Background:

• Conventional lateral flow immunoassays (LFIA) lack sensitivity and quantitative capabilities for modern diagnostics.
• Existing methods are susceptible to environmental interference and have limited detection ranges.

Purpose of the Study:

• To engineer a sensitive photothermal platform (mMZI-LFIA) by integrating optical microfiber Mach-Zehnder interferometers (mMZI) with gold nanoparticle (Au NP)-based LFIA.
• To enable quantitative measurement on LFIA platforms with enhanced sensitivity and stability.

Main Methods:

• Combined a thermo-optical polymer-encapsulated mMZI with Au NP-based LFIA strips.
• Utilized the photothermal effect for analyte concentration-to-temperature change conversion.
• Demonstrated proof-of-concept using prostate-specific antigen detection and Cr3+ test strips.

Main Results:

• Achieved a 11.5-fold increase in sensitivity compared to traditional colorimetric LFIA for prostate-specific antigen detection.
• Established a broad detection range of 0.5-256 ng mL-1 for prostate-specific antigen.
• Demonstrated improved LOD for Cr3+ detection (0.235 ng mL-1).

Conclusions:

• The mMZI-LFIA platform significantly enhances detection sensitivity, accuracy, and reliability.
• This integration enables photothermal quantification without additional thermal equipment.
• Offers a promising pathway for portable photothermal LFIA systems in point-of-care diagnostics.