Characteristic synergistic cytotoxic effects toward cells in graphene oxide dressing with cadmium and copper ions.

The increasing applications of graphene oxide (GO) in bio-medicine, environment and other fields enhance the exposure possibility of human beings to GO. Studies have been performed to address the toxicity of GO; however, little information on the biological consequence of GO with other common disasters is available, especially when cells are co-exposed to GO and common metal ions. To explore the influence and possible mechanisms of such co-exposure scenarios, a series of tests of cell viability, membrane integrity, reactive oxygen species (ROS), cell morphology, and Cd distribution, were conducted. The results showed that the synergistic toxic mechanisms of GO and Cd, initiated from the adhesion of GO on HeLa cells, and followed by the recruitment of Cd ions around the cell membrane, impaired the membrane integrity, morphology and adhesion capability, and triggered cell toxicity. The synergistic toxic mechanism of GO and Cu mainly correlated to ROS, while no obvious relationship with membrane integrity was observed. The findings are envisaged to facilitate the application of GO in biology and related fields.