Double-Enhanced Photothermal Lateral Flow Biosensor Based on Dual Gold Nanoparticle Conjugates

Area of Science:

• Biosensing technologies
• Nanomaterials in diagnostics
• Food safety analysis

Background:

• Bacterial toxins are major causes of foodborne illness, necessitating rapid point-of-care detection.
• Conventional gold nanoparticle-based lateral flow biosensors (LFBs) lack sufficient sensitivity for early toxin detection.

Purpose of the Study:

• To develop a highly sensitive smartphone-integrated photothermal lateral flow biosensor (PLFB) for bacterial toxin detection.
• To enhance detection sensitivity using dual gold nanoparticle conjugates (DGNPs).

Main Methods:

• Developed a PLFB utilizing the localized surface plasmon resonance and photothermal effect of DGNPs.
• Validated enhanced photothermal performance of DGNPs via numerical simulations.
• Applied DGNPs-PLFB for the detection of staphylococcus enterotoxin A (SEA).

Main Results:

• DGNPs demonstrated significantly enhanced photothermal performance compared to single gold nanoparticles (SGNPs).
• The DGNPs-PLFB achieved colorimetric and photothermal limits of detection for SEA at 0.091 and 0.0038 ng mL⁻¹, respectively.
• Achieved a 10.7-fold increase in colorimetric sensitivity and a 255.3-fold increase in photothermal sensitivity compared to SGNPs-LFBs.

Conclusions:

• The smartphone-integrated DGNPs-PLFB offers a simple, rapid, and highly sensitive method for bacterial toxin detection.
• This technology shows great potential for on-site food safety monitoring and diagnostics.