Enhanced Stability and Sensitivity for CA-125 Detection Under Microfluidic Shear Flow Using Polyethylene...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Microfluidic point-of-care (POC) diagnostic tools are crucial for rapid disease detection.
• Integrating biosensors with microfluidic platforms enhances lab-on-a-chip capabilities.
• Limited research exists on biomarker detection stability under microfluidic shear flow conditions.

Purpose of the Study:

• To develop a stable and sensitive biosensor for CA-125 antigen detection in microfluidic systems.
• To evaluate the performance of polyethylene glycol (PEG)-coated biosensors compared to gold nanoparticle (AuNP)-coated biosensors.
• To address the limitations of AuNPs in microfluidic shear flow due to agglomeration.

Main Methods:

• Immobilization of CA-125 antibodies on gold-interdigitated electrodes using a 2 kDa polyethylene glycol (PEG) intermediate layer.
• Fabrication of both PEG-coated and gold nanoparticle (AuNP)-coated capacitive biosensors.
• Evaluation of biosensor stability and sensitivity under static drop and microfluidic shear flow conditions for CA-125 antigen detection.

Main Results:

• The PEG-coated biosensor demonstrated a 2.2 times higher capacitive signal response (5660 pF vs. 2551 pF at 10 kHz) compared to the AuNP-coated biosensor under static conditions.
• The PEG-coated biosensor exhibited significantly better consistency between static and microfluidic shear flow conditions (2.9% Cp decrease) than the AuNP-coated biosensor (32.4% Cp decrease).
• These results indicate enhanced sensitivity and superior stability of the PEG-coated biosensor under microfluidic shear flow.

Conclusions:

• Polyethylene glycol (PEG) serves as an effective intermediate layer for stable antibody immobilization and biomarker detection in microfluidic biosensors.
• The PEG-coated biosensor overcomes the agglomeration limitations of gold nanoparticles (AuNPs), offering improved stability and sensitivity.
• This advancement represents a significant step towards reliable electrical biosensors for point-of-care diagnostic applications, particularly under microfluidic conditions.