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 to 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. • GO functionalized Polycarbonate track-etch membrane electrochemical sensor for SARS CoV-2 detection. • SARS CoV-2 RBD specific antibodies used as receptors. • Antibodies immobilized via traditional and Protein-G mediated methods. • Detection within minutes at femtomolar concentration.