The specific properties that make two-dimensional (2D) nanomaterials attractive, also result in potential risks for the environment and human health. Specifically, the interaction of 2D nanomaterials with biological membranes, which serves as a barrier between intracellular contents and the surrounding environment, has important implications for ecotoxicity. We used a dye-leakage assay to quantitatively assess the disruption of a model phospholipid bilayer membrane by five emerging 2D nanomaterials: graphene oxide (GO), reduced graphene oxide (rGO), molybdenum disulfide (MoS2), copper oxide (CuO), and iron oxide (α-Fe2O3). Dye leakage from the vesicle inner solution, which indicates loss of membrane integrity, was observed for GO, rGO, and MoS2 nanosheets, but not for CuO and α-Fe2O3, suggesting that nanomaterial chemical composition plays an important role during membrane–nanosheet interactions. Induced-aggregation was demonstrated for GO and rGO while physically interacting with lipid vesicles. In contrast, induced-stabilization was observed for MoS2 nanosheets when mixed with lipid vesicles, suggesting that the aggregation mechanism differed between the 2D nanomaterials. No loss of membrane integrity was observed under high oxidative stress, indicating that a physical mechanism rather than chemical oxidation induces lipid membrane disruption. Furthermore, the extent of physical interaction with GO was dependent on total surface area, not edge length, consistent with a physical lipid-extraction mechanism. Overall, lessons learned in this study provide meaningful insight into nanosheet effects on living cells.

Loss of phospholipid membrane integrity induced by two-dimensional nanomaterials

256th National Meeting (2018)

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