Stable aqueous dispersion of superparamagnetic iron oxide nanoparticles protected by charged chitosan derivatives

摘要

This article presents the synthesis and\udcharacterization of biocompatible superparamagnetic\udiron oxide nanoparticles (SPIONs) coated with ultrathin\udlayer of anionic derivative of chitosan. The water-based\udfabrication involved a two-step procedure. In the first\udstep, the nanoparticles were obtained by co-precipita-\udtion of ferrous and ferric aqueous salt solutions with\udammonia in the presence of cationic derivative of\udchitosan. In the second step, such prepared materials\udwere subjected to adsorption of oppositely charged\udchitosan derivative which resulted in the preparation of\udnegatively charged SPIONs. They were found to\uddevelop highly stable dispersion in water. The core size of the nanocoated SPIONs, determined using transmis-\udsion electron microscopy, was measured to be slightly\udabove 10 nm. The coated nanoparticles form aggregates\udwith majority of them having hydrodynamic diameter\udbelow 100 nm, as measured by dynamic light scattering.\udTheir composition and properties were studied using\udFTIR and thermogravimetric analyses. They exhibit\udmagnetic properties typical for superparamagnetic\udmaterial with a high saturation magnetization value of\ud123\ud±\ud12 emu g\ud-\ud1\udFe. Very high value of the measured\udr\ud2\udrelaxivity, 369\ud±\ud3mM\ud-\ud1\uds\ud-\ud1\ud, is conducive for the\udpotential application of the obtained SPIONs as prom-\udising contrast agents in magnetic resonance imaging.