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 in vitro toxicity of GO; however, little information on the in vivo 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 Cd²⁺ distribution, were conducted. The results showed that the synergistic toxic mechanisms of GO and Cd²⁺, initiated from the adhesion of GO on HeLa cells, and followed by the recruitment of Cd²⁺ ions around the cell membrane, impaired the membrane integrity, morphology and adhesion capability, and triggered cell toxicity. The synergistic toxic mechanism of GO and Cu²⁺ 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.