Investigation of the binding constant and stoichiometry of biocompatible cobalt ferrite-based magnetic fluids to serum albumin

In this work we investigated the interaction between citrate-coated cobalt ferrite nanoparticles (CiCo) and serum albumin proteins (BSA), through the fluorescence quenching of the BSA tryptophan residue after the binding of CiCo to specific sites. Two different biocompatible magnetic fluid (BMF) samples containing CiCo stabilized at physiological condition, with different core sizes (5 and 16 nm), were used. The binding constant and the stoichiometry values indicate that the BMF based on the 16 nm particle diameter is less site-specific and more strongly bound to the BSA. (C) 2003 Elsevier B.V. All rights reserved.