Proper design of biofunctionalized ultra-small iron oxide superparamagnetic nanoparticles for biomedical applications

Over the last decade, nanotechnology has become more relevant in medicine. Among magnetic nanomaterials the future of iron oxide nanoparticles (IONPs) for clinical applications relies on their biocompatibility in moderate doses, their ability to be produced in a wide range of sizes and shapes with biofunctionalization potential. Additionally, they show great promise to serve as a cell tracking system in cell-based therapies, and to generate local temperature increases in the magnetic thermotherapy of solid tumours. Thus, the study and development of novel magnetic nanoparticles for biomedical applications is one of the key topics in the field of nanotechnology. Extremely small-sized Fe3O4 superparamagnetic nanoparticles were prepared by coprecipitation, thinly coated with silica and conjugated with FITC, as molecular model specimen. Nanoparticles were characterized by dinamic light scattering (DSL), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD) and surface functional groups and composition were analysed by infrared spectroscopy (FTIR). The aim of this study was to determine the biocompatibility of the magnetic nanoparticles carriers with biofunctional coating (FITC-conjugated) on colon carcinoma CaCo-2 cell line as human cellular model. Phase contrast, immunofluorescence and confocal microscopy analyses were performed to study nanoparticles internalization and up-take. By transmission electron microscopy technique was investigated the effect of their internalization on ultrastructural features and intracellular compartments. Cellular growth and viability resulted unaffected following nanoparticles up-take and lack of toxicity was confirmed at transcriptional and translational level. Finally, even when used at high concentration, the cytotoxicity effect of the nanoparticles was not significant compared with control experiments, demonstrating their high potential in the applications of nanomedicines for a diagnostic and therapeutic tool.