▎ 摘　　要

In this study, the cytotoxicity of graphene oxide (GO) nanosheets with different morphologies regulated with Pb2+ was estimated using A549 cells and an in vitro method. The results showed that after GO interacted with Pb2+, GO could transform to graphite-like, tube-like, and ball-like structures. The cell viability significantly decreased when A549 cells only exposed to GO (called GO group); whilst more cells survived after exposure to GO regulated by Pb2+ (called GO + Pb group). The levels of reactive oxygen species obviously increased in all the groups of Pb, GO, and GO + Pb relative to the control group, which suggested all the exposure of Pb2+, GO, and the mixture of GO and Pb2+ could significantly generate the oxidative stress-lipid peroxidization. GO showed the highest nutrient depletion-induced indirect cytotoxicity. In the GO + Pb group, the cell numbers got approximate 10% increase with respect to the GO group. Moreover, GO had high phospholipid extraction, whilst no phospholipid extraction was observed in the GO + Pb group. After aggregation and/or re-assembly, the membrane puncturing, phospholipid extraction, oxidative stress, nutrient depletion, and sheet adhesion of GO were inhibited to various extent, contributing to the reduced cytotoxicity of GO as well as Pb2+.