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Immunosensor Enhanced with Silver Nanocrystals for On-Chip Prostate-Specific Antigen Detection.
Timothy A Okhai1,2, Kefilwe V Mokwebo3, Marlon Oranzie3
1Clinical Engineering Group, Department of Electrical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0183, South Africa.
Biosensors
|July 25, 2025
Summary
This study introduces a novel electrochemical immunosensor for prostate-specific antigen (PSA) detection. The silver nanocrystal-based sensor offers high sensitivity and selectivity for quantifying PSA levels.
Area of Science:
- Electrochemistry
- Nanomaterials Science
- Biomedical Engineering
Background:
- Prostate-specific antigen (PSA) is a key biomarker for prostate cancer diagnosis and monitoring.
- Sensitive and selective detection methods for PSA are crucial for early diagnosis and effective treatment management.
- Existing detection methods may face limitations in sensitivity, selectivity, or cost-effectiveness.
Purpose of the Study:
- To develop and characterize a novel electrochemical immunosensor for the sensitive and selective quantification of prostate-specific antigen (PSA).
- To utilize silver nanocrystals (AgNCs) for enhanced signal transduction in the immunosensor.
- To evaluate the performance of the fabricated immunosensor in terms of sensitivity, selectivity, stability, and repeatability.
Main Methods:
- Synthesis of silver nanocrystals (AgNCs) via a citrate reduction protocol.
- Fabrication of the immunosensor on a glassy carbon electrode (GCE) involving AgNCs, EDC-NHS, anti-PSA antibody immobilization, and BSA blocking.
- Characterization of AgNCs using SEM, FESEM, XRD, HRTEM, FTIR, UV-Vis, and SAXS.
- Electrochemical characterization using cyclic voltammetry (CV) and performance evaluation using square wave voltammetry (SWV).
Main Results:
- The synthesized AgNCs were thoroughly characterized using multiple microscopy and spectroscopy techniques.
- The fabricated immunosensor demonstrated high sensitivity for PSA detection within a range of 1 to 10 ng/mL, with a low detection limit of 1.14 ng/mL and excellent linearity (R²=0.99%).
- The immunosensor exhibited significant selectivity against common interfering substances and showed good stability and repeatability.
Conclusions:
- The developed AgNC-based electrochemical immunosensor provides a highly sensitive and selective platform for PSA quantification.
- The sensor's performance indicates its potential for reliable clinical application in prostate cancer diagnostics.
- This approach offers a promising alternative for sensitive biomarker detection in point-of-care settings.
