Effect of preparation methods on toxicity of fullerene water suspensions to Japanese medaka embryos

摘要

The physicochemical properties of fullerene water suspensions (nC_(60)) and their subsequent toxicity were influenced by different preparation methods. The nC_(60) suspensions were produced by three methods: toluene exchange (TolC_(60)). DMSO dissolving (DMSOC_(60)). and stirring overtime (AquC_(60)). The particle size, zeta potential, and nC_(60) structure were strongly dependent on both the type of aggregates formed and the test medium addition. Specifically, TolC_(60) exhibited small and spherical closed aggregates, whereas DMSOC_(60) and AquC_(60) presented mesoscale aggregates of smaller spherical aggregates. These differences in the physicochemical properties of nC_(60) determined the embryonic toxicity and oxidative stress of Japanese medaka (Oryzias latipes). The mortality and glutathione (GSH) induction of embryos were ranked in the order of TolC_(60)≥DMSOC_(60)>AquC_(60), and the morphological malformations were in the order of DMSO/ nC_(60)>TolC_(60)>AquC_(60). The mortality of TolC_(60) was attributed to its closely packed fullerene structure, which remained as largely underivatized C_(60). The malformations of DMSOC_(60) might have originated from the co-effect of organic solvent remaining in the fullerene colloid. To summarize, these findings clearly illustrated the need to consider the effect of preparation method on the physicochemical properties when assessing nC_(60) toxicity.