As a new class of xenogenous nanoparticle, quantum dots （QDs） possess the potential to co-exist with Cu^2＋ in human liver. The combined toxicity is thus concerned. Considering QDs and Cu^2＋ are known ROS （reactive oxygen species） inducer, we investigated the combined oxidative stress and corresponding protective strategy using human hepatic L02 cells. The results demonstrated that the presence of a small amount of MPA-CdTe QDs （2 μg/mL） in a Cu^2＋ solution （2.5-20 μg/mL） resulted in a higher toxicity with up to 8-fold cell viability decrease, which was accompanied by cell morphology changes. The combined toxicity was then confirmed as ROS associated oxidative stress with up to 300% and 35% increase of the intracellular ROS level and glutathione S-transferase （GST） activity, respectively. N-acetylcysteine （NAC） can also provide almost complete protection against the induced toxicity. Therefore, the ROS associated oxidant injury might be responsible for the QDs-Cu^2＋/Cu^2＋ induced toxicity and could be balanced through cytoprotective antioxidant enzyme GST.
Yuxia Zhao,Kuangfei Lin,Wei Zhang,Lili Liu State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process,Shanghai 200237,China
