Toxicity of nano gamma alumina to neural stem cells.

Nano alumina, one of the most important nanomaterials, is widely used in diverse areas. It was reported that nano alumina could cross the blood brain barrier to enter the brain. Considering aluminum accumulation in brain is closely related to many neural diseases. We studied the neural toxicity of four nano gamma-alumina samples by using neural stem cells (NSCs) C17.2 as a model. We find that the toxicity of nano gamma-alumina is pretty low, though these alumina particles are easily internalized by cells. The loss of cell viability and membrane integrity are dose-dependent and sample-dependent after alumina exposure. At concentrations lower than 100 microg/mL, no significant toxicity is observed for all alumina samples. When the concentration reaches 200 microg/mL, alumina treated cells begin to loss their activities. No culture period effect (up to 3 days) is observed. Very tiny soluble aluminum and the absorption of culture medium ingredients onto alumina particles do not affect the cell viability. Intracellular reactive oxygen species generation may contribute to the cytotoxicity of alumina particles at high concentration, but it does not induce the apoptosis of NSCs.

In vitro toxicity evaluation of graphene oxide on A549 cells.

Graphene and its derivatives have attracted great research interest for their potential applications in electronics, energy, materials and biomedical areas. However, little information of their toxicity and biocompatibility is available. Herein, we performed a comprehensive study on the toxicity of graphene oxide (GO) by examining the influences of GO on the morphology, viability, mortality and membrane integrity of A549 cells. The results suggest that GO does not enter A549 cell and has no obvious cytotoxicity. But GO can cause a dose-dependent oxidative stress in cell and induce a slight loss of cell viability at high concentration. These effects are dose and size related, and should be considered in the development of bio-applications of GO. Overall, GO is a pretty safe material at cellular level, which is confirmed by the favorable cell growth on GO film.