Polydopamine-assisted Sr immobilization to improve the osteogenesis of a three-dimensional reduced graphene oxide/polypyrrole composite scaffold

Abstract The development of a bone tissue engineering scaffold with a biologically active surface for fast bone cell adhesion, proliferation, and extracellular matrix mineralization has been hotly pursued in recent years. However, most substrate materials do not show enough biological activity. Here, polydopamine-assisted immobilization of strontium (Sr) endows a three-dimensional reduced graphene oxide/polypyrrole (3D rGO/PPY) composite scaffold with higher bioactivity. Compared to the bare 3D rGO/PPY scaffold, 3D rGO/PPY modified with Sr (3D rGO/PPY/PDA/Sr) has a higher surface roughness. Moreover, benefiting from the introduction of Sr, the 3D rGO/PPY/PDA/Sr scaffold can significantly enhance early adhesion and proliferation of MC3T3-E1 cells on the 2nd day of culture. Additionally, ALP activity and extracellular matrix mineralization are distinctly enhanced.