Abstract
This work describes X-ray imaging of mouse using colloid solution of silica coated Au (Au/SiO2) nanoparticles surface modified with poly(ethylene glycol) (PEG) (Au/SiO2/PEG). A colloid solution of Au nanoparticles was prepared by reducing Au ions (III) with sodium citrate. Au/SiO2 nanoparticles were fabricated by a sol–gel method using tetraethylorthosilicate, water and sodium hydroxide in ethanol in the presence of Au nanoparticles surface modified with (3-aminopropyl)trimethoxysilane. A computed tomography value of the Au/SiO2 colloid solution with an Au concentration of 0·083M was as high as 1421·2 Hounsfield units, which was higher than that of a commercial X-ray contrast agent with the same iodine concentration. Surface modification of the Au/SiO2 particles with PEG, or PEGylation of the particle surface, was performed using (3-aminopropyl)trimethoxysilane and PEG for the Au/SiO2 particles. Tissues of mouse could be imaged by injecting the colloid solutions of Au/SiO2 particles or Au/SiO2/PEG particles into it. The PEGylation provided an increase in residence time of particles in the mouse.
We express our thanks to Professor T. Noguchi in College of Science of Ibaraki University, Japan, for his help in the TEM observation.