Comparative effect of quantum dot nanoparticles on the growth of two marine microalgae.

In this study we evaluated the effect of CdSe/ZnS quantum dots (QDs) on the growth of the marine diatom Phaeodactylum tricornutum and of the green alga Dunaliella tertiolecta, as biological models in the marine environment. The results showed that the effect on the growth was species-specific. QDs in the range 1 - 2.5 nM gradually inhibited the growth rate of P. tricornutum, more effectively than equivalent amounts of CdCl2. On the contrary, QDs did not affect the growth rate of D. tertiolecta, rather a modest stimulation was observed in the range 0.5 - 2 nM, suggesting an hormetic response. Our data also showed that P. tricornutum cells can adapt themselves to survive in QD-treated culture media.