Magnetite and silica-coated magnetite nanoparticles are highly biocompatible on endothelial cellsin vitro

Superparamagnetic iron oxide nanoparticles (MNPs) have recently been investigated for biological applications with promising results, owing to their ability to be targeted and heated by magnetic fields. Silica is a very suitable coating material for MNPs, facilitating the loading of targeting moieties and drug delivery. However, the potential toxicity of SiO₂-coated MNPs remains a major concern for clinical application. The synthesis, via wet-chemistry, and physico-chemical characterization of Fe₃O₄ and silica coated (Fe₃O₄-SiO₂) MNPs are here described, examining in vitro cytocompatibility including viability, necrosis, intracellular reactive oxygen species (ROS) generation and apoptosis, in an endothelial cell model. The results showed that both types of SPION are spherical, 10-15 nmin diameter and can be dispersed in water-based media. In vitro characterization revealed both to be highly cytocompatible at 10 μgml^-1 concentration, suggesting their safe use in biomedical applications. Cytotoxicity, including ROS generation and expression of apoptosis activating enzymes (caspase 3), slightly increased at 80 μgml^-1, in a dose dependent manner. Fe₃O₄-SiO₂ nanoparticles induced a higher level of ROS and expression of caspase 3. In conclusion data suggest that both SPION types may be differently aimed in biomedical application in relation to the dose, acting as biocompatible materials, as component of scaffolds, or as a device for theranostics.