Amine modified iron oxide (Fe(3)O(4)) nanoparticles were synthesized by thermal decomposition method and were further used to bio-functionalize by grafting of N-hydroxysuccinimide (NHS) ester of folate and ethylenediami-netetraacetate (EDTA). Fe(3)O(4) nanoparticles of similar to 22 nm were confirmed from X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. FT-IR studies indicated two bands at 1515 cm(-1) and 1646 cm(-1), which can be attributed to carboxylic group and the amide linkage respectively, revealing the conjugation of folate with Fe(3)O(4). The conjugation of the chelating agent showed strong C=O stretch and Fe-O vibrations at 1647 and 588 cm(-1) respectively. The value of saturation magnetization for Fe(3)O(4) nanoparticles was found to be 88 emu/g, which further reduced to 18 and 32% upon functionalization with EDTA and NHS ester folate, respectively. These amine modified Fe(3)O(4) nanoparticles can also be functionalized with other bifunctional chelators, such as amino acids based diethylene triamine pentaacetic acid (DTPA), and thus find potential applications in radio-labeling, biosensors and cancer detection, etc. (C) 2010 Elsevier B.V. All rights reserved.