A Low-Cost Handheld Reconfigurable Impedimetric Readout System for Diagnostics of Viral Infections.

This article presents a portable impedimetric biosensor for detecting infectious diseases, such as SARS-CoV-2 infections. A bio-ready sensing electrode functionalized with SARS-CoV-2 nucleocapsid antibody was employed to quantitatively convert the concentration of nucleocapsid protein (N-protein) into impedance changes. In this article, we proposed a readout system with a dynamic input range of 200- $\Omega $ –1- $\text{M}\Omega $ magnitude and 0°–180° phase. The resolution of this device is 1% and 6.5° for measuring the magnitude and phase, respectively. Herein, we demonstrate and discuss the proposed system’s functionality, sensitivity, and selectivity using the clinical swab samples. As per these results, this readout system is suitable for the detection of N-protein ranging up to 10000 pg/mL with a resolution of 56 fg/mL. The proposed impedimetric sensing system can be adopted for the detection of infectious diseases in the future. This low-cost (< $\$ $ 80) device using off-the-shelf is a unique candidate for batch production purposes during urgent pandemic situations.