Revista de nanomateriales y nanotecnología molecular

Preparation of a Colloid Solution of Au/Silica Core-Shell Nanoparticles Surface-Modified with Cellulose and its X-ray Imaging Properties

Yoshio Kobayashi, Ryoko Nagasu, Tomohiko Nakagawa, Yohsuke Kubota, Kohsuke Gonda and Noriaki Ohuchi

Preparation of a Colloid Solution of Au/Silica Core-Shell Nanoparticles Surface-Modified with Cellulose and its X-ray Imaging Properties

Objective: The aim of this paper is to describe the preparation of a colloid solution of Au nanoparticles that are coated with silica and simultaneously surface modified with carboxymethylcellulose (CMC) (Au/SiO2/CMC) and to investigate the X-ray imaging of mice using the colloid solution.

Methods: The reduction of Au ions (III) with sodium citrate produced Au nanoparticles, and amino groups were introduced on the surface of the Au nanoparticles by using (3-aminopropyl)-trimethoxysilane. The Au nanoparticles with amino groups were silica coated by a sol-gel process using tetraethylorthosilicate, (3-aminopropyl)- triethoxysilane, water and sodium hydroxide in ethanol (Au/SiO2- NH2). After concentrating the as-prepared Au/SiO2-NH2 particle colloid solution by centrifugation, CMC was immobilized on the Au/ SiO2-NH2 particle surface with the addition of CMC to the Au/SiO2- NH2 particle colloid solution.

Results: The Au/SiO2/CMC particles, with a size of 67.4 ± 5.4 nm containing a core of a single Au nanoparticle with a size of 17.9 ± 1.3 nm, were produced using the preparation conditions adopted in the present work. A computed tomography (CT) value that was as high as 344 ± 12 Hounsfield units (HU) was recorded for the Au/SiO2/CMC particle colloid solution with an Au concentration of 0.043 M. Its converted value was calculated by dividing the Au concentration into the recorded CT value and was 8.0×103 HU/M. This value was larger than that of Iopamiron 300, a commercial X-ray contrast agent. The Au/SiO2/CMC particle colloid solution was injected into the tail vein of a mouse and could be used to image the tissues.

Conclusion: The Au/SiO2/CMC particle colloid solution obtained in the present work was successfully used for X-ray imaging.