Amine-Functionalized Fe2O3–SiO2 Core–Shell Nanoparticles With Tunable Sizes

Iron oxide magnetic nanoparticles (MNPs) coated with uniform silica shell were synthesized through thermal decomposition and inverse microemulsion methods. The iron oxide MNPs were further coated with silica shells through hydrolysis reaction. For the resulting core-shell MNPs, size regulation of both the magnetic core and the porous shell were achieved, enabling the modulation of their magnetic properties and magnetic interactions. Core-shell MNPs were finally functionalized with amine groups, and immobilized on gold surface due to charge-neutral amine/gold interactions. It was observed that the immobilization process was enhanced under external magnetic field.