Amino acid functionalized magnetite nanoparticles in saline solution

We report amino acid functionalized magnetite nanoparticles with particle diameters, ranging from 3 to 10 nm. We synthesized them in one-step in a saline solution. The saturation magnetizations (M(s)s) were determined to be 57.98 and 45.20 emu/g at 300 K for L-glutamic acid and L-lysine functionalized magnetite nanoparticles, respectively. Especially, L-lysine functionalized magnetite nanoparticles showed an excellent colloidal stability of >a year or so. This excellent colloidal stability, a high saturation magnetization, and a nearly monodisperse particle diameter of the L-lysine functionalized magnetite nanoparticles will be useful for biomedical applications. (C) 2008 Elsevier B.V. All rights reserved.