Design and fabrication of an electrochemical nano-biosensor for the quick sensing of SARS CoV-2

Graphene oxide (GO) emerged as a biosensing material due to its patternable features, electron transfer properties, high functionality, and greater surface area that enables sensitive point-of-use applications. This report outlines the design of an electrochemical biosensor composed of a polycarbonate track-etched (PCTE) nano-sieve platform with two silver electrodes, which can detect the surface glycoprotein of the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), specifically the Spike protein (S-protein), in a rapid and sensitive manner. To fabricate the GO material, we utilized the modified Hummers' method to convert graphite powder. In this study, we covalently immobilized SARS-CoV-2 specific antibodies onto an EDC-NHS functionalized nanosieve platform using two methods i.e., conventional or traditional method and protein-G mediated. The immobilization of these antibodies on the nanosieve platform was achieved through bio-linkage, resulting in specific interactions between the spike protein and the antibodies. These interactions led to a partial blockage of the nanosieve, this led to a considerable decrease in the ionic current for a voltage range of 1.0–2.0 V. The linear range was set between 3.6 mM and 3.6 aM. The detection limit was in nM in traditional method which was notably decreased to fM in protein-G mediated antibodies immobilization. Notably, when testing two non-specific proteins, bovine serum albumin (BSA) and influenza virus, under the same settings, there was no significant change in the current. This nano-biorecognition platform, or nanobiosensor, offers improved stability and higher sensitivity due to the integration of minor GO laminates.