Functionalized Gold Nanorods are dissolved in DI water. The PEGylated gold nanorods exhibit good biocompatibility and can be dispersed in various types of polar organic solvents, including ethanol, methanol, acetone, acetonitrile, DMF, DMSO and PBS. The biocompatible PEG-20 gold nanorods exhibit extremely high photothermal conversion efficiencies and large scattering cross sections at their plasmon resonance wavelengths.