In this research, water-soluble functionalized gold nanorods (Au NRs) with low toxicity were synthesized by a seed-mediated growth method. For this purpose, a seed solution of the gold nanoparticles was added to the growth solution containing a weak reducing agent to form a controlled size of gold nanorods. After that, to explore the applicability of gold nanoparticles in biomedicine, particularly in photothermal therapy as a noninvasive therapeutic tool, the prepared Au NRs were functionalized using (11-Mercaptoundecyl)tetra(ethylene glycol) as a monohydroxy thioalkylated PEG (MUTEG) ligand, for the first time. To confirm the formation of Au NRs and determination of their size and aspect ratio, UV−Vis spectroscopy and TEM techniques were applied. The CHNS analysis was employed to characterize the attached MUTEG ligands on the surface of the Au NRs. The HeLa cells were used to determine the cytotoxicity of the prepared Au-MUTEG NRs. The surface of the prepared Au-MUTEG NRs was conjugated with BSA to obtain AuMUTEG−BSA NRs, as the final product, and confirmed by FT-IR analysis. The zeta potential analysis was also used to determine the charge and stability of the functionalized Au-MUTEG and Au-MUTEG−BSA NRs in comparison with Au NRs.
