Fluorescent Magnetic Bioprobes by Surface Modification of Magnetite Nanoparticles

Bimodal nanoprobes comprising both magnetic and optical functionalities have been prepared via a sequential two-step process. Firstly, magnetite nanoparticles (MNPs) with well-defined cubic shape and an average dimension of 80 nm were produced by hydrolysis of iron sulfate and were then surface modified with silica shells by using the sol-gel method. The Fe₃O₄@SiO₂ particles were then functionalized with the fluorophore, fluorescein isothiocyanate (FITC), mediated by assembled shells of the cationic polyelectrolyte, polyethyleneimine (PEI). The Fe₃O₄ functionalized particles were then preliminary evaluated as fluorescent and magnetic probes by performing studies in which neuroblast cells have been contacted with these nanomaterials.