Palma, SI, Rodrigues CA, Carvalho A, Morales PM, Freitas F, Fernandes AR, Cabral JS, Roque ACA.
2015.
A value-added exopolysaccharide as a coating agent for MRI nanoprobes. Nanoscale. (7):14272-14283.
AbstractFucopol, a fucose-containing exopolysaccharide (EPS) produced by the bacterium Enterobacter A47 DSM 23139 using glycerol as a carbon source, was employed as a new coating material for iron oxide magnetic nanoparticles (MNP). The coated particles were assessed as nanoprobes for cell labeling by Magnetic Resonance Imaging (MRI). The MNP were synthesized by a thermal decomposition method and transferred to aqueous medium by ligand-exchange reaction with meso-2,3-dimercaptosuccinic acid (DMSA). Covalent binding of EPS to DMSA-stabilized nanoparticles (MNP-DMSA) resulted in a hybrid magnetic-biopolymeric nanosystem (MNP-DMSA-EPS) with a hydrodynamic size of 170 nm, negative surface charge at physiological conditions and transverse to longitudinal relaxivities ratio, r2/r1, of 148. In vitro studies with two human cell lines (colorectal carcinoma - HCT116 - and neural stem/progenitor cells - ReNcell VM) showed that EPS promotes internalization of nanoparticles in both cell lines. In vitro MRI cell phantoms also showed superior performance of MNP-DMSA-EPS in ReNcell VM, for which iron dose-dependent MRI signal drop was obtained at relatively low iron concentrations (12 - 20 µg Fe/ml) and short incubation time. Furthermore, ReNcell VM multipotency was not affected by culture in the presence of MNP-DMSA or MNP-DMSA-EPS for 14 days. Our study suggests that Fucopol-coated MNP represent useful cell labeling nanoprobes for MRI.