Assembly Preparation of Multilayered Biomaterials with High Mechanical Strength and Bone-Forming Bioactivity

The creation of a bone substitute with both excellent mechanical strength and bioactivity is still a challenge in bone tissue engineering biomaterials. To this end, inspired by the microstructure of nacre, multilayered graphene oxide/chitosan/calcium silicate (GO/CTS/CS) biomaterials were successfully prepared via a bottom-up assembly approach. The GO/CTS/CS biomaterials emulated the "brick and mortar" layered microstructure via chemical assembly and the multilayered helical cylinder macrostructure. In addition, benefiting from the interface interactions in the layered microstructure as well as the multilayered helical cylinder macrostructure, the GO/CTS/CS biomaterials possessed high flexural strength (137.2 MPa), compressive strength (80.2 MPa), toughness (1.46 MJ/m3), and specific strength (124.7 MPa Mg–1 m–3), which are close to those of cortical bone. Furthermore, because of the bioactive chemical components of GO and CS, the multilayered GO/CTS/CS biomaterials significantly improved osteogenesis and angiogenesis in vitro. Moreover, the multilayered GO/CTS/CS biomaterials showed enhanced in vivo bone-forming ability due to the contributions of bioactive chemical components and the multilayered helical cylinder macrostructure. This work not only provides a biomaterial with excellent mechanical strength and bioactivity but also offers a strategy for fabrication of high-performance biomaterials based on bioinspired chemistry and engineering.