Biocompatible superparamagnetic carriers of chondroitin sulfate

The present study reports on the fabrication, morphological and structural characterizations, magnetic and biological tests of a biocompatible superparamagnetic carrier comprising iron oxide nanoparticle (ION) surface-functionalized with chondroitin sulfate (ChS), labelled ION@ChS. The reported ION@ChS sample is produced by alkaline coprecipitation of Fe²⁺ and Fe³⁺ ions in aqueous media in the presence of ChS. Fourier Transform infrared, Raman and x-ray photoelectron spectroscopies provide evidences for coordination of the ChS molecule (mainly through sulfonic groups) onto the ION's surface. Transmission electron microscopy reveals that the ION@ChS are nearly spherical (mean diameter = 8.2 nm ± 0.1) and almost monodispersed (diameter dispersity = 0.11 ± 0.01), while dynamic light scattering and electrophoretic mobility measurements confirm the presence of ChS at the ION's surface, providing mean hydrodynamic diameter (~100 nm) and very high negative zeta potential (around −50 mV). Moreover, the ION@ChS is superparamagnetic at room temperature, with no coercivity or remanence. Cell viability tests performed by means of the MTT assay indicates that ION@ChS shows no cytotoxiciy effect (p < 0.05). Therefore, one can anticipate potential biotechnological applications of the ION@ChS sample for site-specific delivery of ChS as well as a contrast agent in magnetic resonance imaging.