title: A value-added exopolysaccharide as a coating agent for MRI nanoprobes.
abstract: Fucopol, 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 (MNPs). The coated particles were assessed as nanoprobes for cell labeling by Magnetic Resonance Imaging (MRI). The MNPs were synthesized by a thermal decomposition method and transferred to an aqueous medium by a 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, a negative surface charge under physiological conditions and transverse to longitudinal relaxivity 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 showed a superior performance of MNP-DMSA-EPS in ReNcell VM, for which the iron dose-dependent MRI signal drop was obtained at relatively low iron concentrations (12-20 μg Fe per ml) and short incubation times. 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 MNPs represent useful cell labeling nanoprobes for MRI.
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. cecilia.roque@fct.unl.pt.
authors.forename: Susana I C J
authors.initials: SI
authors.lastname: Palma
authors.forename: Carlos A V
authors.initials: CA
authors.lastname: Rodrigues
authors.forename: Alexandra
authors.initials: A
authors.lastname: Carvalho
authors.forename: Maria del Puerto
authors.initials: Mdel P
authors.lastname: Morales
authors.forename: Filomena
authors.initials: F
authors.lastname: Freitas
authors.forename: Alexandra R
authors.initials: AR
authors.lastname: Fernandes
authors.forename: Joaquim M S
authors.initials: JM
authors.lastname: Cabral
authors.forename: Ana C A
authors.initials: AC
authors.lastname: Roque
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003287:Contrast Media / Q000737:chemistry*; D004754:Enterobacter / Q000378:metabolism; D005290:Ferric Compounds / Q000737:chemistry; D045325:HCT116 Cells; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D018613:Microscopy, Confocal; D058953:Neural Stem Cells / Q000166:cytology; D010316:Particle Size; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D004113:Succimer / Q000737:chemistry
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D011135:Polysaccharides, Bacterial; C000499:ferric oxide; D004113:Succimer