Preparation, characterization and application of superparamagnetic iron oxide encapsulated with N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride

Superparamagnetic iron oxide nanocrystals (SPION) and their colloidal solutions of magnetic nanoparticles (ferrofluid) appear to contribute to the magnetite imaging applications. Here we present an aqueous ferrofluid in physiological pH and its cell tracking potential. In situ coating method was adapted to synthesize N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC)-coated SPION. Characterization results reveal their features as follows: (1) z-average diameter of 274.1 ± 1.934 nm; (2) polydispersity index (PDI) of 0.135 ± 0.029; (3) zeta potential of 11.4 ± 0.410 mV; (4) iron concentration of 5.4 mg Fe/ml; (5) stable in both water and normal saline; (6) uptake by a variety of cell lines and (7) little cytotoxicity. Finally, islet grafting experiments demonstrated the potential usefulness of this product as a MRI contrast agent for cell tracking.