Immunosensor Based on Printed Circuit Board for Protein Detection

Nowadays, many electrochemical immunosensors have emerged, tailored to specific applications by customizing commercial electrodes. The electrode surface was modified to attach specific antibodies, enabling the capture and detection of antigens through physical measurement techniques. In this paper, we developed a simple and low-cost electrochemical immunosensor based on the printed circuit board (PCB) platform for protein detection. The proposed immunosensor configuration was designed using CAD software and fabricated on FR4 substrate, a commonly used material in printed circuit boards. Subsequently, a thin layer of gold was applied over the copper layer to create a metal substrate. The electrode shape can be easily designed and fabricated to the desired shape using this approach. The electrode surface modification process was carried out to facilitate the binding of the antibody to the gold substrate. A round-shaped gold layer with a diameter of 3 mm was fabricated on the PCB, and an electrochemical sensor configuration with a parallel structure was designed. This configuration comprised two PCBs structured with gold electrodes placed in parallel, maintaining a distance of 5 mm between the two electrodes. This configuration allowed for convenient sensor usage. The working electrode was separated from the counter electrode to mitigate potential negative effects during the surface modification process. Experiment results have demonstrated the sensor can detect the 5 µM bovine serum albumin (BSA). The presence of BSA was verified by both fluorescent images under the microscope and impedance measurements. With achieved results, the proposed immunosensor configuration shows promising potential for low-cost and easy fabrication in bio-detection applications.