Biocompatibility analysis of halloysite clay nanotubes

The biocompatibility of four different halloysite clay nanotubes (HNT-N,-U,-P,-S), from various deposits in the world, was evaluated. More precisely, we tested their cytogenetic effects through MTT assay (for cytotoxic ef-fects), and CBMN assay (for genotoxic effects) on mammalian cell cultures (CHO, HeLa, and HepG2 cell lines). Our results indicated a generally high level of biocompatibility of these new-generation products, however at high concentrations, and long times of exposition, we observed a moderate level of toxicity. Thus, we suggest caution in the future use of great amounts of HNTs due to their effects on living organisms.