Preparation of Gd Complex-Immobilized Silica Particles and Their Application to MRI

• Published in: ISRN nanotechnology 2013-01, Vol.2013, p.1-6
• Main Authors: Kobayashi, Yoshio, Morimoto, Hikaru, Nakagawa, Tomohiko, Kubota, Yohsuke, Gonda, Kohsuke, Ohuchi, Noriaki
• Format: Article
• Language: English
• Subjects: Colloiding; Colloids; Ethanol; Ethyl alcohol; Nanotechnology; Silicon dioxide; Sol gel process
• ISSN: 2090-6072; 2090-6072
• DOI: 10.1155/2013/908614

A preparation method for Gd-ethylenediaminetetraacetic acid disodium salt dihydrate (ETDA) complex-immobilized silica particles (Gd-EDTA/SiO2) is proposed. Preparation of spherical silica particles was performed by a sol-gel method at 35°C using 0.2 M tetraethylorthosilicate, 25 M H2O, and 0.01 M NaOH in ethanol, which produced silica particles with an average size of 80.4±14.9 nm. Immobilization of Gd-EDTA on the silica particles was conducted at 35°C by introducing amino groups on the silica particles with (3-aminopropyl)trimethoxysilane at pH 3 (NH2/SiO2) and then making Gd-EDTA act on the NH2/SiO2 particles at pH 5. The as-prepared Gd-EDTA/SiO2 particle colloid solution was concentrated up to a Gd concentration of 0.347 mM by centrifugation. The sphere structure of Gd-EDTA/SiO2 particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated Gd-EDTA/SiO2 colloid solution revealed good MRI properties. A relaxivity value for T1-weighted imaging was as high as 5.15 mM−1 s−1, that was comparable to that for a commercial Gd complex contrast agent.