Figure 8.

Changes in the degree of enhancement of the Raman scattering spectrum of a sample of the RBD of the SARS-CoV-2 S glycoprotein with reactive thiol groups upon application of a thin silver film onto the protein sample bound with the SERS-active substrate. (1) The SERS spectrum of the RBD upon additional application of a thin silver film onto the protein sample bound to the surface of the SERS-active substrate. The spectrum is not normalized. (2) The SERS spectrum of the RBD without additional application of a thin silver film onto the protein sample bound to the surface of the SERS-active substrate. The normalization factor for the tryptophan residue band at about 755 cm⁻¹ is 9.0.