Investigation on thyroglobulin and myoglobin using graphene-enhanced Raman spectroscopy as a tool

Herein, for the first time, we report the experimental investigation on thyroglobulin (Tg) and myoglobin (Mb) using graphene-enhanced Raman spectroscopy as a tool. Tg is the protein precursor of thyroid hormones, while Mb can be used as an early cardiac protein biomarker. In the beginning, the absorption properties of Tg and Mb are investigated with the help of a UV-visible spectrophotometer. Later, Tg and Mb are dispersed over two different glass substrates by drop-casting 10 μL of protein solutions with a concentration of 1 μM and their conventional Raman scattering (CRS) spectra are recorded. However, none of the vibrational modes are significant in their CRS spectra. Therefore, the graphene-enhanced Raman scattering (GERS) spectra of Tg and Mb are recorded with a high signal-to-noise ratio. The number and intensity of the vibrational modes in the GERS spectra are found to strongly depend upon the probed location. Finally, the assignment of all the observed vibrational modes is performed.