Surface-Enhanced Raman Scattering Spectra of Thioflavin T: Manifestation of the Electromagnetic and Molecular Enhancement Mechanisms

Surface-enhanced Raman scattering spectra of the fluorescent probe thioflavin T and its complex with amyloid fibrils adsorbed on silver hydrosol were investigated at excitation wavelengths 473, 532, and 633 nm. The enhancement mechanisms of the principal vibrational bands of the dye molecules were determined. The molecules were bound to the surface of the silver nanoparticles through the thiazole ring sulfur atom while retaining their native conformation. Active sites of the molecule that were responsible for its incorporation into amyloid fibrils were identified.