Synthesis-Dependent Surface Defects and Morphology of Hematite Nanoparticles and Their Effect on Cytotoxicity in Vitro

In this study, we investigate the toxicity of hematite (alpha-Fe2O3) nanoparticles on the Madin-Darby Canine Kidney (MDCK) cell line. The oxide particles have been synthesized through two different methods and annealing conditions. These two methods, spray precipitation and precipitation, resulted in particles with rod-like and spherical morphology and feature different particle sizes, surface features, and magnetic properties. Through flow cytometry it was found that particle morphology heavily influences the degree to which the nanomaterials are internalized into the cells. It was also found that the ability of the nanoparticles to generate free radicals species is hindered by the formation of tetrahedrally coordinated maghemite-like (gamma-Fe2O3) spinel defects on the surfaces of the particles. The combination of these two factors resulted in variable cytotoxic effects of the hematite nanoparticles synthesized with different conditions. This article highlights the importance on the fabrication method, materials properties, and surface characteristics on the cytotoxicity of hematite nanomaterials.