TITLE:
Synthesis and Surface Modification of Spindle-Type Magnetic Nanoparticles: Gold Coating and PEG Functionalization
AUTHORS:
Juan Mendez-Garza, Biran Wang, Alexandra Madeira, Christophe Di Giorgio, Georges Bossis
KEYWORDS:
Core@shell; Spindle-Type; Hematite; Magnetic Particles; Gold Coating; Fluorescent-PEG
JOURNAL NAME:
Journal of Biomaterials and Nanobiotechnology,
Vol.4 No.3,
June
26,
2013
ABSTRACT: In this paper, we describe the
synthesis of gold coated spindle-type iron nanoparticles and its surface
modification by a thiolated fluorescently-labelled polyethylene glycol (PEG)
polymer. A forced hydrolysis of ferric salts in the presence of phosphate ions
was used to produce α-Fe2O3 spindle-type particles. The oxide powders were first reduced to α-iron under high temperature and
controlled dihydrogen atmosphere. Then, the resulting magnetic spindle-type
particles were covered by a shell of gold. The formation of the core@shell
structure was driven by a redox-transmetalation reaction between iron(0) at the
surface of particles and a gold(III) salt. Protected against oxidation, the
Fe@Au core@shell nanoparticles were then grafted with a water soluble
fluorescent-PEG-thiol. TEM, XRD, EDX and
measurements of magnetic properties of particles confirm 1) the conversion of hematite into iron and 2) their subsequent surface protection with a gold shell. Furthermore, the
functionalization of the gold nanoparticle surface with a PEG carrying a fluorescent dye was unambiguously attested by
confocal laser scanning microscopy.