X-ray imaging technique using colloid solution of Au/silica core-shell nanoparticles

Abstract

This work describes X-ray imaging of mouse using a colloid solution of silica-coated Au (Au/SiO2) nanoparticles. A colloid solution of Au nanoparticles with a size of 16.9 nm was prepared using hydrogen tetrachloroaurate (III) trihydrate as Au source and sodium citrate as reducing reagent. Silica coating of the Au nanoparticles was performed by modifying the Au nanoparticle surface with (3-aminopropyl)trimethoxysilane and then by depositing silica nuclei generated through a sol–gel reaction of tetraethyl orthosilicate in water/ethanol initiated with sodium hydroxide on the surface-modified surface, which produced Au/SiO2 particles with a size of 136.4 nm. A computed tomography value of the Au/SiO2 colloid solution with an Au concentration of 0.036 M was as high as 1,184.8 Hounsfield units, which was quite higher than that of a commercial X-ray contrast agent with the same iodine concentration as the Au concentration. Tissues of mouse could be imaged by injecting the Au/SiO2 particle colloid solution into them.