title: Covalent coupling of gum arabic onto superparamagnetic iron oxide nanoparticles for MRI cell labeling: physicochemical and in vitro characterization.
abstract: Gum arabic (GA) is a hydrophilic composite polysaccharide derived from exudates of Acacia senegal and Acacia seyal trees. It is biocompatible, possesses emulsifying and stabilizing properties and has been explored as coating agent of nanomaterials for biomedical applications, namely magnetic nanoparticles (MNPs). Previous studies focused on the adsorption of GA onto MNPs produced by co-precipitation methods. In this work, MNPs produced by a thermal decomposition method, known to produce uniform particles with better crystalline properties, were used for the covalent coupling of GA through its free amine groups, which increases the stability of the coating layer. The MNPs were produced by thermal decomposition of Fe(acac)3 in organic solvent and, after ligand-exchange with meso-2,3-dimercaptosuccinic acid (DMSA), GA coating was achieved by the establishment of a covalent bond between DMSA and GA moieties. Clusters of several magnetic cores entrapped in a shell of GA were obtained, with good colloidal stability and promising magnetic relaxation properties (r2 /r1 ratio of 350). HCT116 colorectal carcinoma cell line was used for in vitro cytotoxicity evaluation and cell-labeling efficiency studies. We show that, upon administration at the respective IC50 , GA coating enhances MNP cellular uptake by 19 times compared to particles bearing only DMSA moieties. Accordingly, in vitro MR images of cells incubated with increasing concentrations of GA-coated MNP present dose-dependent contrast enhancement. The obtained results suggest that the GA magnetic nanosystem could be used as a MRI contrast agent for cell-labeling applications.
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Susana I C J
authors.initials: SI
authors.lastname: Palma
authors.affiliation: CENIMAT - I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Carvalho
authors.affiliation: UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Silva
authors.affiliation: UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Martins
authors.affiliation: Departamento de Biomateriales y Materiales Bioinspirados, Instituto de Ciencia de Materiales de Madrid, ICMM/CSIC, 28049, Madrid, Spain.
authors.forename: Marzia
authors.initials: M
authors.lastname: Marciello
authors.affiliation: UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.|CQE, Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1490-001, Lisboa, Portugal.
authors.forename: Alexandra R
authors.initials: AR
authors.lastname: Fernandes
authors.affiliation: Departamento de Biomateriales y Materiales Bioinspirados, Instituto de Ciencia de Materiales de Madrid, ICMM/CSIC, 28049, Madrid, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: del Puerto Morales
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Ana C A
authors.identifier: http://orcid.org/0000-0002-4586-3024
authors.initials: AC
authors.lastname: Roque
mesh_terms: D002460:Cell Line; D003287:Contrast Media / Q000737:chemistry / Q000494:pharmacology; D005290:Ferric Compounds / Q000737:chemistry / Q000494:pharmacology; D006170:Gum Arabic / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D013194:Staining and Labeling / Q000379:methods
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide; D006170:Gum Arabic
keywords: DMSA; HCT116 cell line; cell labeling; colorectal carcinoma; gum arabic; in vitro MRI; iron oxide magnetic nanoparticles; magnetic resonance imaging