Influence of the covalent immobilization of graphene oxide in poly(vinyl alcohol) on human osteoblast response

The differences in the response of human Saos-2 osteoblasts to nanocomposites of poly(vinyl alcohol) (PVA) and 1.5 wt.% graphene oxide (GO) prepared by covalent linking (PVA/GO-c) and simple blending (PVA/GO-m) have been evaluated through different biocompatibility parameters. The effects produced on osteoblasts by these two nanocomposites were analysed in parallel and compared with the direct action of GO and with the effect of PVA films without GO. The intracellular content of reactive oxygen species (ROS) and the levels of interleukin-6 (IL-6) were measured to evaluate oxidative stress induction and protective response, respectively. The results demonstrate that the combination of GO with PVA reduces both the proliferation delay and the internal cell complexity alterations induced by GO on human osteoblasts. Moreover, the covalent attachment of GO to the PVA chains increases both cell viability and IL-6 levels, reducing both apoptosis and intracellular ROS content when compared to simple blending of both materials. The use of this strategy to modulate the biointerface reduces the toxic effects of graphene while preserving the reinforcement characteristics for application in tissue engineering scaffolds, and has enormous interest for polymer/graphene biomaterials development. (C) 2015 Elsevier B.V. All rights reserved.