Synthesis and characterization of carboxymethyl dextran-coated Mn/Zn ferrite for biomedical applications

Previous studies have shown that magnetic nanoparticles possess great potential for various in vivo applications such as magnetic resonance imaging contrast enhancement, tissue repair, cancer treatment agents, and controlled drug delivery. Many of these applications require that magnetic nanoparticles be colloidally stable in biological media. The goal of this study was to obtain a magnetic fluid produced by the colloidal suspension of manganese/zinc ferrite (MZF) nanoparticles that could be stably dispersed in aqueous solution throughout the range of physiological pH and ionic strength. These superparamagnetic nanoparticles were stabilized through steric repulsion by coating with biologically compatible carboxymethyl dextran (CMDx). Samples of the resultant magnetic fluid were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), X-ray diffraction (XRD), zeta potential measurements, dynamic light scattering, transmission electron microscopy (TEM), and SQUID magnetometry. Results show that we obtained superparamagnetic metal-oxide crystals with composition of Mn_0.24Zn_0.76Fe₂O₄. Cell viability measurements show the material is non-toxic to MCF-7 and CaCo-2 cell lines at concentrations of up to 7.5 mg/mL of particle fraction for contact time of up to 48 h.