Glycoconjugated chitosan stabilized iron oxide nanoparticles as a multifunctional nanoprobe

Surface modification of iron oxide nanoparticles (IOPs) with functional polymer can be used for the preparation of multifunction nanoprobes. The present study dealt with the preparation of glycoconjugated chitosan (GC) stabilized IOPs (GC-IOPs). GC was prepared by direct coupling of lactobionic acid (LA) on chitosan. GC was subsequently grafted onto the surface of IOPs to enhance colloid stability. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), transmission electron microscopy (TEM), dynamic light scattering (DLS), electrophoretic light scattering (ELS) and superconducting quantum interference device (SQUID) measurements were performed to investigate the properties of nanoparticles. FT-IR and XRD analysis of GC-IOPs showed that backbone and side chain functionality of chitosan and phase purity of IOPs remained intact during conjugation. TEM observations revealed that GC-IOPs were spherical (8-10 nm) but the dispersibility and stability in acetated buffer (pH 7.4) linearly increased with degree of substitution (DS) of chitosan. The specific magnetization of GC-IOPs was varied with DS from 19.50 to 41.56 emu/g. This variation in colloid stability and specific magnetization suggests that DS can be varied to tailor the degree of dispersion and magnetic properties of IOPs. The advantage of GC-IOPS is the ability to achieve a homogeneous nanosize particle distribution and specific surface functionality for bioconjugation. These characteristics make the GC-IOPs a potential candidate for biomedical research and clinical diagnosis. (C) 2009 Elsevier B.V. All rights reserved.