The association between nC₆₀and 17α-ethinylestradiol (EE2) decreases EE2 bioavailability in zebrafish and alters nanoaggregate characteristics

Abstract

Manufactured nanoparticles (NPs) released into surface waters will associate with other substances and these interactions may affect environmental fate and bioavailability of NPs and the associated substances. We investigated the association between aqueous aggregates of C60 (nC60) and synthetic estrogen, 17α-ethinylestradiol (EE2), and considered nC60 physicochemistry and EE2 bioavailability (by measuring vitellogenin (vtg1A/B) gene expression) in zebrafish. Bioavailability of EE2 was reduced with increasing concentration of nC60 (P < 0.05), and bioavailability of EE2 decreased further after aging 28 d with nC60. Reduction in EE2 bioavailability was correlated with computed surface area of nC60, and reduced bioavailability of EE2 upon aging was consistent with absorption of EE2 within nC60 aggregates. Size and zeta potential of nC60 particles were affected by EE2 (1 μg/L) and also by aging (28 d) in aqueous phase. Results indicate that nC60 can reduce bioavailability of some substances and influence environmental fate and transport of associated substances.