Paper-based microfluidic sensing device for label-free immunoassay demonstrated by biotin-avidin binding interaction

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Efficient disease diagnosis and rapid screening are critical for effective disease control.
• Current point-of-care diagnostic methods face challenges in quantitative, rapid immunoassay detection.
• Developing portable, cost-effective biosensors is essential for ambulatory healthcare settings.

Purpose of the Study:

• To develop a novel fabrication method for carbon nanotube bundles for paper-based microfluidic devices.
• To demonstrate quantitative, label-free immunoassay detection using the developed biosensor.
• To assess the performance characteristics, including sensitivity and detection time, of the biosensor.

Main Methods:

• Fabrication of a paper-based microfluidic sensing device incorporating deposited carbon nanotube bundles.
• Utilizing direct current change measurement for label-free detection of biotin-avidin binding.
• Performing quantitative analysis of target analyte concentration.

Main Results:

• Achieved a sensitivity of 0.33 μA/ng mL⁻¹ for the biosensor.
• Determined a minimal detectable analyte concentration of 25 ng/mL.
• Reduced detection time to 500 seconds compared to conventional immunoassays.

Conclusions:

• The developed paper-based biosensor enables rapid, quantitative, and label-free immunoassay detection.
• The biosensor exhibits portability, fast response, simple operation, and low cost.
• This technology holds significant potential for advancing rapid disease screening devices in point-of-care applications.