Cellular and in vivo toxicity of functionalized nanodiamond in Xenopus embryos

Abstract

Recently, nanodiamond particles (ND) have emerged as a promising tool in the field of nanobiotechnology. However, studies about the impact of ND on living organisms are still limited to raw materials and primarily confined to in vitro studies. In this work, we investigated the cytotoxicity and in vivo toxicity of ND correlated with their chemical surface functionality (-OH, -NH₂ or -CO₂H). Two model systems have been used, human embryonic kidney 293 (HEK293) cells and Xenopus laevis embryos. Cell viability assays showed that ND were not cytotoxic to HEK293 cells for concentrations below 50 μg mL⁻¹. Our data suggest that the cytotoxicity may be due to the affinity of cationic particles for the negatively charged cell membrane. In parallel, visual monitoring of microinjected early-stage embryos showed a potential embryotoxicity and teratogenicity for carboxylated ND-CO₂H. ND seem to have a negative impact on the gastrulation and neurulation stages inducing phenotypical abnormalities and high mortality.