Collagen is the most abundant protein of the ECM and, for this reason, collagen hydrogels provide an in-vivo like three-dimensional environment suitable for creating tissue equivalents and studying cell-matrix interactions. Nevertheless, collagen hydrogels exhibit limited mechanical properties if compared to native collagen tissues. Chemical cross-linking is a common method to synthesize hydrogels but cross-linking agents are usually cytotoxic against cells. For this reason, physically cross-linked hydrogels are considered an attractive alternative for cell culture applications. Graphene oxide (GO) has been recently attracting attention due to its unique properties such as large surface area, flexibility, high mechanical strength, high dispersibility, hydrophilicity, biocompatibility and ability to promote cell proliferation.