Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped virus with a surface heavily decorated with stick-like glycosylated spike (S) structural proteins, as well as three other major structural proteins: nucleocapsid (N), matrix (M), and envelope (E) proteins . The structure of the S protein consists of three protomers, each containing S1 and S2 subunits, consisting of 672 and 588 amino acids, respectively . The S1 subunit is particularly important because it contains the receptor binding domain (RBD) that plays a crucial role in SARS-CoV-2 virus infection. It is now well known that SARS-CoV-2 infects epithelial cells of the human respiratory system. The interaction between the RBD of the S protein and angiotensin-converting enzyme II (ACE2), which is expressed on the host cells, and the S2 subdomain are required for membrane fusion . In addition, the RBD determines the binding affinity to the host receptor, viral specificity and mortality . For these reasons, the RBD of S protein provides a suitable target to develop biosensors for detection of SARS-CoV-2 .