Modulated surface of single-layer graphene controls cell behavior

In recent years graphene has become a very popular material in biomedicine studies. Its potential use varies from implant coating to biosensor fabrication. For application of graphene in this field an understanding of the interactions between the substrate and various types of cells is necessary. This work is focused on early behavior of a human osteoblastic cell line on graphene sheets with different surface treatments (hydrogen or oxygen). The cell adhesion was investigated at an early time point of incubation (2 h) and a late one (48 h). Studies were performed in the presence and the absence of fetal bovine serum (FBS), as the proteins contained in the FBS play a crucial role in the cell adhesion. Despite the fact that the graphene substrates used had a comparable surface topography, their different wettability caused an unexpected inverse effect on cell adhesion and growth. The single-layer graphene treated with hydrogen (1-LG, hydrophobic surface) enhanced cell proliferation, whereas the single-layer graphene treated with oxygen (1-LG-O, hydrophilic surface) caused cell response as good as tissue-culture plastic specially treated for cell cultivation.