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Updated: Feb 12, 2026
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Gold Nanoparticle Synthesis
Published on: July 10, 2021
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Ultrasensitive interdigitated capacitance immunosensor using gold nanoparticles.
Hojjat Alizadeh Zeinabad1,2,3, Hedayatollah Ghourchian1,4, Mojtaba Falahati3
1Laboratory of Bioanalysis, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
Nanotechnology
|April 10, 2018
Summary
This study presents a novel, portable immunosensor for detecting hepatitis B surface antigen (HBsAg). The device utilizes gold interdigitated electrodes and nanoparticles for highly sensitive capacitance detection, enabling rapid diagnosis.
Area of Science:
- Biosensors and diagnostics
- Nanomaterials in sensing
- Electrochemical immunosensing
Background:
- Interdigitated electrodes (IDEs) offer enhanced capacitance detection sensitivity.
- Hepatitis B surface antigen (HBsAg) detection is crucial for diagnosing Hepatitis B.
- Current detection methods may lack sensitivity, portability, or speed.
Purpose of the Study:
- To develop a highly sensitive, compact, and portable immunosensor for rapid HBsAg detection.
- To optimize antibody immobilization techniques for improved efficiency and oriented binding.
- To leverage nanomaterials for signal amplification and enhanced detection limits.
Main Methods:
- Fabrication of a gold interdigital capacitor on IDEs.
- Formation of a self-assembled monolayer (SAM) of 2-mercaptoethylamine for antibody immobilization.
- Carboxyl group activation and oriented immobilization of primary antibodies.
- Utilizing gold nanoparticles conjugated with secondary antibodies for signal enhancement.
Main Results:
- The developed immunosensor demonstrated high sensitivity (0.22 nF.pg ml-1).
- A wide linear detection range was achieved (5 pg ml-1 to 1 ng ml-1).
- A low detection limit of 1.34 pg ml-1 was obtained at a signal-to-noise ratio of 3.
Conclusions:
- The novel gold interdigital capacitor-based immunosensor offers a sensitive and rapid method for HBsAg detection.
- The optimized antibody immobilization strategy and nanoparticle amplification contribute to enhanced performance.
- The compact and portable design holds potential for point-of-care diagnostics.
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