7th World Nano Conference

Biography

Biography: Yoshio Kobayashi

Abstract

X-ray imaging of mice using a colloid solution of Au nanoparticles that were coated with silica and subsequently surface-modified with carboxymethylcellulose (CMC) (Au/SiO2/CMC) was performed in this work. The silica-coating for Au nanoparticles and the amination for silica-coated particles were simultaneously performed in the presence of the Au nanoparticles with a size of 17.9 nm, which were prepared by reducing Au ions (III) with sodium citrate in water at 80°C and by surface-modifying the Au nanoparticles with (3-aminopropyl)-trimethoxysilane, by a sol-gel process using tetraethylorthosilicate, (3-aminopropyl)-triethoxysilane, water and sodium hydroxide (Au/SiO2-NH2). The surface modification of Au/SiO2-NH2 particles with CMC was performed by simply adding CMC with carboxyl groups that react with an amino group to the Au/SiO2-NH2 particle colloid solution. The as-prepared the Au/SiO2/CMC particle colloid solution was concentrated by centrifugation for measurements using computed tomography (CT). Figure 1 shows a photograph of the concentrated particle colloid solution and a transmittance electron microscopy image of the Au/SiO2/CMC particles in the concentrated colloid solution. Most particles contained a single core of the Au nanoparticles. Their particle size was 67.4±5.4 nm. A CT value of the Au/SiO2/CMC particle colloid solution with a Au concentration of 0.043 M was as high as 344±12 Hounsfield units (HU). This value corresponded to 8.0×103 HU/M with respect to the Au concentration, which was larger than that of Iopamiron 300, a commercial X-ray contrast agent. Mouse tissues were imaged following injection of the Au/SiO2/CMC particle colloid solution.