Evaluation of iron oxide nanoparticle biocompatibility

Nanotechnology is an exciting field of investigation for the development of new treatments for many human diseases. However, it is necessary to assess the biocompatibility of nanoparticles in vitro and in vivo before considering clinical applications. Our characterization of polyol-produced maghemite gamma-Fe2O3 nanoparticles showed high structural quality. The particles showed a homogeneous spherical size around 10 nm and could form aggregates depending on the dispersion conditions. Such nanoparticles were efficiently taken up in vitro by human endothelial cells, which represent the first biological barrier to nanoparticles in vivo. However, gamma-Fe2O3 can cause cell death within 24 hours of exposure, most likely through oxidative stress. Further in vivo exploration suggests that although gamma-Fe2O3 nanoparticles are rapidly cleared through the urine, they can lead to toxicity in the liver, kidneys and lungs, while the brain and heart remain unaffected. In conclusion, gamma-Fe2O3 could exhibit harmful properties and therefore surface coating, cellular targeting, and local exposure should be considered before developing clinical applications.