Coupling Capillary-Driven Microfluidics with Lateral Flow Immunoassay for Signal Enhancement
Pooya Azizian1,2, Jasmina Casals-Terré2, Elena Guerrero-SanVicente1
1Energy and Engineering Department, Leitat Technological Center, 08225 Terrassa, Barcelona, Spain.
Biosensors
|August 25, 2023
Summary
This study introduces a 3D-printed microfluidic device that enhances lateral flow immunoassay sensitivity for salivary cortisol detection. The automated washing step significantly reduces background noise, improving stress response analysis.
Area of Science:
- Microfluidics
- Analytical Chemistry
- Biotechnology
Background:
- Microfluidics enhances analytical techniques, particularly lateral flow immunoassays (LFIA) requiring higher sensitivity for low-concentration analytes.
- Salivary cortisol measurement is crucial for assessing physiological stress, but low concentrations necessitate sensitive detection methods.
- Existing LFIA methods often lack automated steps, limiting sensitivity and increasing background noise.
Purpose of the Study:
- To develop and validate a capillary-driven microfluidic device integrated with LFIA for enhanced salivary cortisol detection.
- To implement an automated washing step within the microfluidic device to reduce background noise and improve assay sensitivity.
- To quantitatively measure cortisol levels in saliva using the novel microfluidic-enhanced LFIA system.
Main Methods:
- A multilevel microfluidic chip was fabricated using 3D printing with photocurable black resin and sealed with an optically clear adhesive.
- The microfluidic chip was coupled to a lateral flow strip for a competitive immunoassay protocol.
- An automated washing step was integrated to remove unbound quantum-dot-labeled antibodies, followed by fluorescence spectroscopy for detection.
Main Results:
- The microfluidic device successfully quantified clinically relevant salivary cortisol concentrations in a buffer.
- The automated washing step effectively reduced background noise by removing unbound labeled antibodies from the nitrocellulose membrane.
- The 3D-printed valve design prevented reagent cross-contamination, ensuring assay integrity.
Conclusions:
- The developed microfluidic device significantly improves the sensitivity of LFIA for salivary cortisol detection.
- The automated washing step is key to reducing background noise and enhancing quantitative analysis of stress biomarkers.
- This cost-effective, self-powered, and robust device is suitable for non-expert users in point-of-care stress monitoring.
