A novel interdigitated capacitor based biosensor for detection of cardiovascular risk marker

Area of Science:

• Biosensor Technology
• Nanomaterials Science
• Biomedical Engineering

Background:

• Elevated C-reactive protein (CRP) levels indicate cardiovascular disease risk and inflammation.
• Accurate and sensitive detection of CRP is crucial for early disease diagnosis.

Purpose of the Study:

• To develop a novel capacitive biosensor for detecting C-reactive protein (CRP) antigen.
• To utilize interdigitated gold electrodes on a nanocrystalline diamond surface for enhanced detection capabilities.

Main Methods:

• Fabrication of a capacitive biosensor with gold interdigitated electrodes (GID) on a nanocrystalline diamond (NCD) surface.
• Functionalization of the GID-NCD surface with antibodies for CRP-antigen capture.
• Detection of CRP-antigen via capacitive/dielectric-constant measurements and analysis using the Cole-Cole model.

Main Results:

• Immobilization of antibodies on the GID-NCD surface was confirmed using FT-IR and contact angle measurements.
• A significant increase in relaxation time constant (tau) from 10(-16)-10(-13)s to 10(-11)s was observed upon CRP-antigen binding.
• The biosensor demonstrated concentration-dependent (25-800 ng/ml) and frequency-dependent (50-350 MHz) responses to CRP-antigen.

Conclusions:

• The developed GID-NCD based capacitive biosensor shows promise for sensitive and specific detection of CRP-antigen.
• This technology has the potential for early diagnosis of diseases by detecting elevated levels of protein risk markers.
• Further optimization could lead to a valuable tool for clinical diagnostics.