Freestanding membranes from graphene-based materials feature promising mechanical properties, including high strength and toughness. Further, composites of graphene oxide (GO) and biomaterials have been prepared to combine their respective mechanical stability and flexibility. For instance, Tsukruk and co-workers fabricated ultra robust GO/cellulose membranes and GO/silk fibroin (SF) membranes by depositing the different components alternatingly via spin coating. For the fabrication of the GO/cellulose composites, they used rod-shaped cellulose nanocrystals resulting in a maximum toughness of 3.9 MJm -3 for a GO content of 59.1 wt%. In the case of the GO/SF composites increasing volume fractions of GO were incorporated into the SF matrix resulting in a maximum toughness of 2.4 MJm -3 at 23.5 vol% GO.