Hierarchical ZnO Nanotube/Graphene oxide Nanostructures Endow Pure Zn Implant with Synergistic Bactericidal Activity and Osteogenicity

Zinc (Zn) material has recently become a rising biodegradable metal in orthopedic applications owing to its critical physiological functions and degradation characteristics. However, the unsatisfactory cytocompatibility due to the locally high concentration of Zn ions liberated during degradation accompanied with lack of antibacterial property and osteogenesis severely obstruct the clinical adoption of pure Zn implants. To address these challenges, we construct hierarchical ZnO nanotube/graphene oxide nanostructures (GO-An-Zn) on the pure Zn substrates via anodic oxidation followed by silk fibroin-graphene oxide self-assembly in the present study. The resultant surface displays superior bacteria-killing performances against both Gram-negative and Gram-positive bacteria. Moreover, osteoblasts on the dexamethasone-laden hierarchical micro/nanostructured Zn (GO-Dex-An-Zn) shows the enhanced cell compatibility and osteogenicity, outperforming those on pure Zn substrates. It is mainly attributed to the synergi...