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Self-Powered PEC Cathodic Immunosensor for CA125 Detection Based on the Cu2O Photocathode and the CdS/PANI Photoanode
Shulei Wang1, Xuyong Wang2, Faqiong Zhao1
1College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei Province 430072, P. R. China.
ACS Sensors
|November 21, 2025
Summary
This study developed a novel self-powered biosensor using a CdS/PANI photoanode and Cu2O photocathode. This highly sensitive immunosensor accurately detects cancer biomarkers like CA125 with improved performance.
Area of Science:
- Materials Science
- Electrochemistry
- Biotechnology
Background:
- Photoelectrochemical (PEC) biosensors face challenges with false positives from anodic photocurrent modulation and low sensitivity in cathodic systems.
- Existing PEC sensor designs require external power sources, limiting practical applications.
Purpose of the Study:
- To develop a highly sensitive and reliable self-powered PEC biosensor by creating a novel CdS/PANI heterojunction material.
- To establish a dual-photoelectrode system for enhanced cathodic response and improved sensor performance.
- To demonstrate the sensor's capability for detecting cancer biomarkers, specifically carbohydrate antigen CA125.
Main Methods:
- Synthesized CdS nanoparticles and encapsulated them with polyaniline (PANI) via a hydrothermal method to create a CdS/PANI heterojunction photoanode.
- Constructed a self-powered system using the CdS/PANI photoanode and a Cu2O photocathode, facilitating electron migration due to Fermi-level differences.
- Modified the Cu2O electrode with gold nanoparticles (Au NPs) and immobilized CA125 antibodies for specific biomarker detection.
Main Results:
- The dual-photoelectrode system exhibited a significantly enhanced cathodic response (up to 23 times stronger than a three-electrode system), indicating high sensitivity.
- The developed immunosensor achieved a wide detection range (0.001-100 ng mL−1) and a low detection limit (0.26 pg mL−1) for CA125.
- The sensor demonstrated excellent stability, reproducibility, anti-interference capabilities, and practical applicability, with potential for detecting other biomarkers.
Conclusions:
- The CdS/PANI heterojunction material and the self-powered dual-photoelectrode system effectively overcome the limitations of traditional PEC biosensors.
- The developed immunosensor offers a promising platform for sensitive, stable, and reliable detection of disease biomarkers.
- The adaptable sensing platform holds potential for broader applications in clinical diagnostics and disease monitoring.
