Microfluidic integrated capacitive biosensor for C-reactive protein label-free and real-time detection

Area of Science:

• Biomedical Engineering
• Biosensor Technology
• Microfluidics

Background:

• Capacitive biosensors offer label-free detection capabilities.
• Microfluidic systems enable precise sample handling and integration.
• Three-dimensional (3D) interdigital electrodes enhance sensor performance.

Purpose of the Study:

• To develop and validate a microfluidic chip integrated with a mass-producible 3D capacitive biosensor.
• To enable continuous, on-site detection of cardiac and periodontitis biomarkers.
• To assess the biosensor's specificity, sensitivity, and limit of detection.

Main Methods:

• Fabrication of a microfluidic chip bonded with a 3D interdigital capacitor biosensor.
• Surface functionalization including gold thiol modification, EDC/sulfo-NHS activation, and antibody bioconjugation.
• Characterization using fluorescent methods and X-ray photoelectron spectroscopy (XPS) for antibody immobilization confirmation.
• Label-free detection of C-reactive protein (CRP) using the developed biosensor.

Main Results:

• Successful immobilization of C-reactive protein (CRP) antibodies confirmed by XPS and fluorescence.
• Demonstrated high specificity and sensitivity of the microfluidic-integrated 3D capacitive biosensor.
• Achieved a limit of detection (LOD) of approximately 1 pg mL^-1 for label-free CRP detection.
• Continuous on-site monitoring of cardiac and periodontitis biomarkers was successfully performed.

Conclusions:

• The developed microfluidic chip with a 3D capacitive biosensor is a mass-producible platform.
• The biosensor enables high-performance, continuous, on-site detection of relevant biomarkers.
• This technology holds promise for point-of-care diagnostics and health monitoring.