The study of the structure influence of surface-modified gold/silica nanoshells with the small functional molecules

Gold nanoshells' surface were modified by different functional small molecular containing mercapto group respectively, such as cysteamine (Cys), cystamine (CYS), mercaptosuccinic acid (MSA), and mercaptoethanol (ME). The investigations of dynamic light scatter (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV-Vis spectra demonstrated that Cys and CYS with amine groups presented a significant devastation on the core/shell structure of gold nanoshells, which lead to the obvious aggregation and the disappearance of the NIR resonance of the nanoparticles. However, the surface-modification with MSA and ME had no obvious effect on the core/shell structure and the NIR response of the gold nanoshells. It is possibly due to the bonding of amine groups in Cys and CYS with the gold layers of the nanoshells by electrostatic and coordination interaction.