Electrochemical study of N-acetyl neuraminic acid at gold-modified screen-printed carbon electrodes for a glycoprotein sensor of SARS-CoV-2

An electrochemical sensor of SARS-CoV-2 spike glycoprotein S1 has been developed using N-acetyl neuraminic acid (Neu5Ac) as the biosensing agent based on the interaction between Neu5Ac with the N-terminal domain of spike glycoprotein S1. Gold-modified screen-printed carbon electrodes (Au-SPCEs), prepared by electrochemical deposition of gold particles on a screen-printed carbon electrode surface, were used to detect the presence of the SARS-CoV-2 from the change in the electrochemical behavior of Neu5Ac. Cyclic voltammetry of Neu5Ac in phosphate buffer solution pH 7.6 using Au-SPCEs yielded a couple of oxidation and reduction peaks at potentials of +0.6 and 0.1 V (vs Ag/AgCl), respectively. The currents of both peaks linearly increased with the Neu5Ac concentrations in the range from 0 to 200 mu M. A sensitivity of 0.77 mA/mM and 0.47 mA/mM for reduction and oxidation currents were observed, respectively, with estimated detection limits (LODs) of 51.05 mu M and 35.77 mu M. In the presence of SARS-CoV-2 spike glycoprotein S1, these current peaks decreased. At an optimum contact time of 30 min, a linear correlation to the current change of the reduction peaks was observed for the spike glycoprotein S1 over the concentration range 0 to 0.01 mu g/mL. An estimated LOD of 0.7 ng/mL could be achieved with excellent stability (2.18% RSD value for n = 10), indicating that the sensor is promising for use in real applications of SARS-CoV-2 spike glycoprotein S1 detection. An electrochemical-based sensor for the detection of SARS-CoV-2 spike glycoprotein S1 has been developed based on its interaction with N-acetyl neuraminic acid using gold-modified screen-printed carbon electrodes (Au-SPCEs). Neu5Ac generates current responses via cyclic voltammetry with an Au-SPCE, and its binding to SARS CoV-2 glycoprotein reduces the electrochemical responses on the same electrode. A linear decrease in the electrochemical response to the concentration of SARS CoV-2 glycoprotein S1 indicates that a detection method for SARS CoV-2 virus can be developed by using Neu5Ac as the sensing agent.