Effects of ZnO nanomaterials on Xenopus laevis growth and development.

The objectives of this study were to quantify uptake and developmental effects of zinc oxide nanomaterials (nano-ZnO) on Xenopus laevis throughout the metomormosis process. To accomplish this, X. laevis were exposed to aqueous suspensions of 40–100nm nano-ZnO beginning in-ovo and proceeding through metamorphosis. Nanomaterials were dispersed via sonication methods into reconstituted moderately hard water test solutions. A flow-through system was utilized to decrease the likelihood of depletion in ZnO concentration. Exposure to 2mg/L nano-ZnO significantly increased mortality incidence to 40% and negatively affected metamorphosis of X. laevis. Tadpoles exposed to 2mg/L nano-ZnO developed slower as indicated by tadpoles with an average stage of 56 at the conclusion of the study which was significantly lower than the control tadpole stages. No tadpoles exposed to 2mg/L of nano-ZnO completed metamorphosis by the conclusion of the study. Tadpoles exposed to 0.125mg/L nano-ZnO experienced faster development along with larger body measurements indicating that low dose exposure to nano-ZnO can stimulate growth and metamorphosis of X. laevis.