Interdigitated gold nanowires for impedimetric detection of SARS-CoV-2 antibodies

In the current COVID-19 pandemic that we are facing, it has become evident that the development of biosensors that can aid in the different stages of screening and surveillance: infection, disease progression and recovery, is extremely important. We developed a system that can be used for the detection of SARS-CoV-2 antibodies that are present during and after the infection. Our sensor chips were composed of six sensing devices, each of these containing interdigitated gold nanowires. The surfaces of the mentioned nanowires were functionalized with proteins of the SARS-CoV-2 so that the antibodies present in solution can bind to them. The detection of such antigen-antibody binding events was performed using the impedance spectroscopy technique. For this purposes, an AC signal over a range of frequencies (20 Hz-1 MHz) was applied to the sensor chips and the changes in impedance and phase were measured. The change in the overall impedance of the system was correlated to antigen-antibody binding events. The developed sensing system is a versatile platform that could be easily adapted to detect relevant target-analyte pairs in different diseases.