A Novel Microelectrode Based on Joule Heating and Impedance Spectroscopy for Inducing and Monitoring the Aggregation of HCV-Specific Probes

Second Author's Department

Institute of Global Health & Human Ecology

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https://doi.org/10.3390/s25113312

All Authors

Reda Abdelbaset Omar E. Morsy Mariam Hossam Eldin Sherif M. Shawky Yehya H. Ghallab Yehea Ismail

Document Type

Research Article

Publication Title

Sensors

Publication Date

6-1-2025

doi

10.3390/s25113312

Abstract

Highlights: What are the main findings? A new on-chip microelectrode was designed to induce and monitor the aggregation of HCV RNA-attached gold nanoparticles (AuNPs). The microelectrode effectively induces the aggregation of RNA-attached AuNPs through controlled Joule heating. Impedance spectroscopy was utilized to monitor the aggregation process in real time. Integrating Joule heating and impedance spectroscopy enables on-chip system integration and reduces the detection time for nanoparticle aggregation, enhancing its bioanalytical utility. What are the implications of the main findings? The developed microelectrode can heat a droplet to a specific temperature. It successfully induces color change based on the presence of hepatitis C virus (HCV) RNA. Impedance readings are used to monitor the aggregation process. The world urgently needs new methods to quickly and efficiently detect mutated viruses. An RNA-AuNP-based colorimetric biosensor is a highly sensitive, specific, and cost-effective tool that enables rapid, visual detection of target molecules for applications in disease diagnostics, environmental monitoring, and forensic analysis. An RNA-AuNP-based colorimetric biosensor requires precise control over nanoparticle dispersion and aggregation, which can be achieved using temperature regulation. A novel on-chip microelectrode is proposed to induce and monitor the aggregation of RNA-attached gold nanoparticles (AuNPs) through Joule heating and impedance spectroscopy. The proposed platform is implemented based on printed circuit board (PCB) technology, which has many advantages, such as fast and easy design and fabrication, low power consumption, and low costs. Joule heating is the process in which the energy of an electric current is converted into heat as it flows through a resistance. Impedance spectroscopy is an analytical technique that measures a system’s electrical response to an applied AC signal across a range of frequencies, providing insights into a sample’s dielectric properties. The results validate that the fabricated microelectrode is capable of heating a 20 µL droplet to 75 °C within 30 s, utilizing a low power input of only 3.75 watts and successfully inducing a color change based on the presence of hepatitis C virus (HCV) RNA, while impedance readings are used to monitor the aggregation.

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