Electron Microscopy Observations of the Au Nanorods and Au Nanorod/SiO₂ Nanocapsules

Abstract

An in-depth analysis of the morphology of Au nanorod/SiO₂ nanocapsules was performed by scanning transmission electron microscopy (STEM) imaging, secondary electron (SE) imaging, bright-field (BF) imaging, and high-angle annular dark-field (HAADF) imaging. These detailed analyses and high X-ray computerized tomography (CT) values provided key information for the administration of Au nanorod/SiO₂ nanocapsules into the blood of mice. Au, which is a heavy element, exhibits a high X-ray CT value. STEM images were recorded to clearly analyze the morphology of the Au nanorods and Au nanorod/SiO₂ nanocapsules. The results obtained from SE images, BF images, and HAADF images revealed that Au nanorods are covered by SiO₂ and that Au nanorod/SiO₂ nanocapsules are highly dispersed. Furthermore, 3D tomography reconstruction was performed by using STEM observation. Three-dimensional tomography reconstruction revealed a spatial structure and provided highly reliable information on the Au nanorod/SiO₂ nanocapsules developed in this study.