Eriko Kawamata, Tomoya Inose, Yoshio Kobayashi
Abstract: The present work describes methods for fabricating multilayered core-shell nanoparticles composed of silica (SiO2) as a core, gadolinium compound (GdC) as an inner shell, and SiO2 as an outer shell (SiO2/GdC/SiO2) toward colloidally-stable, inert magnetic resonance imaging contrast agent, and for surface-modifying the SiO2/GdC/SiO2 nanoparticles toward immobilization of functional molecules on the SiO2/GdC/SiO2. SiO2 nanoparticles (particle size by transmission electron microscopy (TEM): 28.6±12.6 nm) were produced by a sol-gel method using tetraethylorthosilicate (TEOS) and methylamine in water/ethanol solution. GdC-coated SiO2 nanoparticles (SiO2/GdC) (GdC shell thickness by TEM: 35.9±4.9 nm) were synthesized by a homogeneous precipitation method using water/propanol solution containing the SiO2 nanoparticles, Gd(NO3)3, urea and polyvinylpyrrolidone. Succeeding SiO2-coating of the SiO2/GdC nanaoparticles was performed by using TEOS and NaOH in the presence of SiO2/GdC nanoparticles. Consequently, SiO2/GdC/SiO2 nanoparticles (SiO2 shell thickness by TEM: 8.5±2.7 nm) could be obtained. The SiO2/GdC/SiO2 nanoparticles were successfully surface-modified by using 3-aminopropyltrimethoxysilane for amination, and by followingly using succinic anhydride for carboxylation.
Keywords: Multilayer, Core-shell, Nanoparticle, Silica, Gadolinium, Sol-gel, Homogeneous precipitation, Surface-modification
Date Published: November 4, 2019 DOI: 10.11159/ijtan.2019.002View Article