[Raman spectrum study of 3.3'-diethylthiatri carbocyanine iodide].

3.3'-Diethylthiatricarbocyanine iodide (DTTC) dye is an important infrared Raman probe molecule, and has received great attention in the past decades due to their potential applications in Raman imaging, single cell detection, and tumor marker. In the present work, ordinary Raman, surface enhanced Raman scattering (SERS), and theoretical Raman spectra were given to estimate the Raman spectrum of DTTC suspension. More specifically, the original gold nanospheres (60-nm diameter) and gold nanorods (NRs) were encoded with DTTC and stabilized with a layer of thiol-polyethylene glycol (PEG) as Raman reporter, and SERS data were obtained from the samples. Density functional theory (DFT) calculation was applied to calculate the optimized Raman spectra of DTTC water solvent on a B3LYP/6-31G level. Subsequently, the obtained experimental spectra from the DTTC were carefully compared with the theoretically calculated spectra. From the spectra comparation, good agreements were obtained between the theoretical and experimental results. This work will facilitate the development of ultrasensitive SERS probes for advanced biomedical applications.