Synthesis and characterization of gold nanoshells for biomedical applications

Gold nanoshells are a new type of nanoparticles including dielectric cores with a continuous thin layer of gold. By varying the core diameter, shell thickness, and the ratio of these parameters, the optical properties of gold nanoshells can be tuned to have maximum absorption in the visible and near infrared spectrum range. The purpose of this research was to synthesize gold coated SiO2 nanoshells for biomedical applications particularly laser tissue soldering. Nanoshells were synthesized using Stober method. The nanoshells were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, UV-visible spectroscopy and atomic force microscopy. The Fourier transform infrared spectroscopy confirmed the functionalization of the surfaces of silica nanoparticles with NH2 terminal groups. A tunable absorption was observed between 470-600 nm with a maximum range of 530-560 nm. Based on the X-ray diffraction, three main peaks of Au (111), (200) and (220) were identified. Also, atomic force microscopy results showed that the diameter of silica core was about 100 nm and the thickness of gold shell about 10 nm. This result showed that it is possible to use these nanoshells with visible and infrared lasers for biomedical applications.