To test for consequences of an exposure of brain cells to copper oxide nanoparticles (CuO-NPs), we synthesised and characterised dimercaptosuccinate-coated CuO-NPs. These particles had a diameter of around 5 nm as determined by transmission electron microscopy, while their average hydrodynamic diameter in aqueous dispersion was 136 ± 4 nm. Dispersion in cell-culture medium containing 10% fetal calf serum increased the hydrodynamic diameter to 178 ± 12 nm and shifted the zeta potential of the particles from -49 ± 7 mV (in water) to -10 ± 3 mV. Exposure of cultured primary brain astrocytes to CuO-NPs increased the cellular copper levels and compromised the cell viability in a time-, concentration- and temperature-dependent manner. Application of CuO-NPs in concentrations above 100 µM copper (6.4 µg/ml) severely compromised the viability of the cells, as demonstrated by a lowered 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction capacity, a lowered cellular lactate dehydrogenase activity and an increased membrane permeability for the fluorescent dye propidium iodide. Copper internalisation as well as cell toxicity of astrocytes exposed to CuO-NPs were similar to that observed for cells that had been incubated with copper salts. The CuO-NP-induced toxicity was accompanied by an increase in the generation of reactive oxygen species (ROS) in the cells. Both, ROS formation and cell toxicity in CuO-NP-treated astrocytes, were lowered in the presence of the cell-permeable copper chelator tetrathiomolybdate. These data demonstrate that CuO-NPs are taken up by cultured astrocytes and suggest that excess of internalised CuO-NPs cause cell toxicity by accelerating the formation of ROS.

中文翻译：

---

氧化铜纳米颗粒在培养的原代脑星形胶质细胞中的摄取和毒性。

为了测试脑细胞暴露于氧化铜纳米颗粒（CuO-NPs）的后果，我们合成并表征了巯基琥珀酸酯包覆的CuO-NPs。通过透射电子显微镜测定，这些颗粒的直径为约5nm，而它们在水分散体中的平均流体动力学直径为136±4nm。在含有10％胎牛血清的细胞培养基中进行分散可将流体动力学直径增加至178±12 nm，并将粒子的zeta电位从-49±7 mV（在水中）转移至-10±3 mV。培养的原代脑星形胶质细胞暴露于CuO-NPs以时间，浓度和温度依赖性方式增加细胞铜水平并损害细胞活力。浓度超过100 µM铜（6.4 µg / ml）的CuO-NPs严重损害了细胞的活力，如降低的3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴化物还原能力，降低的细胞乳酸脱氢酶活性和增加的荧光染料碘化丙啶膜渗透性所证明的。铜内在化以及暴露于CuO-NPs的星形胶质细胞的细胞毒性与已与铜盐孵育的细胞相似。CuO-NP诱导的毒性伴随着细胞中活性氧（ROS）生成的增加。在可渗透细胞的铜螯合剂四硫代钼酸盐的存在下，CuO-NP处理的星形胶质细胞的ROS形成和细胞毒性均降低。