How important is the study of assay interference prior to nanotoxicity assessment? Case study

Most of the toxicity assays were developed for the evaluation of conventional drug compounds in vitro. In fact, researchers have realized that not all cytotoxic and genotoxic assays are appropriate for the evaluation of nanoparticle toxicity as several nanoparticles are capable to interfere with these methods. For instance, the binding and possible inactivation of assay components involved and/or the interference with colorimetric detection are examples of nanoparticle interference on the cytotoxic assays. For a correct assessment of the toxicity of the nanoparticles under evaluation, possible nanoparticle-assay interactions need to be identified. In the present work was evaluated the possible interferences between 3 nanomaterials (TiO2 nanoparticles, nanokaolin clay and TiO2 nanoparticles immobilized in nanokaolin substrates) and the cytotoxicity (MTT, neutral red uptake (NRU), alamar blue (AB) and LDH) and genotoxicity (alkaline comet assay) assays under evaluation.N/