Rapid and highly sensitive immunoassay using an ultra-thin immuno-wall microfluidic device with a sequential...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Immunotechnology

Background:

• Development of sensitive and rapid diagnostic tools is crucial for early disease detection.
• Existing immunoassay platforms often face limitations in sensitivity, speed, or complexity.
• Microfluidic devices offer miniaturization and enhanced control for bioassays.

Purpose of the Study:

• To develop a novel, rapid, and highly sensitive immunoassay platform using an ultra-thin immuno-wall microfluidic device.
• To implement a sequential fluorescence signal increment method for enhanced detection.
• To evaluate the platform's performance for biomarker detection, specifically targeting SARS-CoV-2 spike protein.

Main Methods:

• Fabrication of an ultra-thin immuno-wall using photolithography with a water-soluble photopolymer and immobilized streptavidin.
• Immobilization of biotin-conjugated antibodies onto the immuno-wall for biomarker capture.
• Application of a sequential fluorescence signal increment method with dual fluorescence-labeled antibodies.
• Optimization of the immuno-wall thickness to minimize nonspecific binding and improve signal-to-noise ratio.

Main Results:

• The immunoassay platform demonstrated a limit of detection of 0.01 ng/mL for SARS-CoV-2 spike protein.
• The total detection time was reduced to 30 minutes, comparable to rapid antigen tests.
• The ultra-thin immuno-wall design effectively reduced nonspecific binding, enhancing assay specificity and sensitivity.

Conclusions:

• The developed ultra-thin immuno-wall microfluidic platform offers a rapid and highly sensitive method for biomarker detection.
• This technology shows significant potential for early-phase disease diagnosis, including infectious diseases.
• The platform's ease of use and performance metrics make it a promising alternative to existing diagnostic methods.