Integrated OLED as excitation light source in fluorescent lateral flow immunoassays

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Lateral flow immunoassays (LFIA) are widely used for point-of-care (POC) diagnostics.
• Traditional LFIA systems often rely on external readers or have limited sensitivity.
• Quantum dots (QDs) offer bright fluorescence but require efficient excitation sources.

Purpose of the Study:

• To investigate the integration of organic light-emitting diodes (OLEDs) as on-chip excitation sources for QD-LFIA systems.
• To develop a sensitive, low-cost, and disposable lab-on-chip diagnostic platform.
• To compare the performance of OLED-excited QD-LFIA with conventional gold nanoparticle (Au NP) LFIA.

Main Methods:

• Fabrication of thin-film phosphorescent green OLEDs on plastic substrates.
• Integration of OLEDs and color filters with QD-LFIA test lines.
• Utilization of CdSe/ZnS QDs for fluorescence detection and Au NPs for conventional detection.
• Quantification of visual sensitivity using grayscale analysis of digital images.

Main Results:

• OLED-QD-LFIA demonstrated significantly higher signal intensity (7-8x) and signal-to-noise ratio (SNR) compared to Au NP-LFIA.
• The limit of detection (LOD) for OLED-QD-LFIA was 7x lower (3 nM at S/N=3).
• Successful integration of OLEDs and filters suggests potential for scalable roll-to-roll manufacturing.

Conclusions:

• OLED integration provides an effective on-chip excitation source for QD-LFIA.
• The developed system offers superior sensitivity and performance for POC diagnostics.
• This approach paves the way for sensitive, rapid, and cost-effective disposable diagnostic devices.