The interactions of fullerene C60 and Benzo(?)pyrene influence their bioavailability and toxicity to zebrafish embryos

This study aimed to assess the toxicological consequences related to the interaction of fullerene nanoparticles (C) and Benzo(?)pyrene (B(?)P) on zebrafish embryos, which were exposed to C and B(?)P alone and to C doped with B(?)P. The uptake of pollutants into their tissues and intra-cellular localization were investigated by immunofluorescence and electron microscopy. A set of biomarkers of genotoxicity and oxidative stress, as well as functional proteomics analysis were applied to assess the toxic effects due to C interaction with B(?)P. The carrier role of C for B(?)P was observed, however adsorption on C did not affect the accumulation and localization of B(?)P in the embryos. Instead, C doped with B(?)P resulted more prone to sedimentation and less bioavailable for the embryos compared to C alone. As for toxicity, our results suggested that C alone elicited oxidative stress in embryos and a down-regulation of proteins involved in energetic metabolism. The C + B(?)P induced cellular response mechanisms similar to B(?)P alone, but generating greater cellular damages in the exposed embryos. Once C nanoparticles and B(?)P meet in water, they reciprocally affect their bioavailability and, by consequence, their toxicity to organisms.