Fig. 2. A schematic representation of the steps involved in fabrication of GCE and functionalization process for the SARS-CoV-2 spike protein sensing.

Step 1: The photolithography process was used to prepare SU-8 electrodes, followed by pyrolysis process to convert the polymer structures into glassy carbon. Step 2: The GCE was treated with 4% glutaraldehyde aqueous solutions for 2 h. Step 3: The glutaraldehyde-modified GCE was incubated with the anti-SARS-CoV-2 antibody for 1 h. Step 4: GCE was incubated with different concentrations of SARS-CoV-2 spike protein solution (100 µL) for 20 min. Step 5: Electrochemical (CV/EIS) measurements were carried out