ZnO and ZnS Hybrid Film Enhances the Bone Regeneration Performance of Zinc-Based Implants

Zinc-based biodegradable metal materials have garnered significant attention in recent years due to their favorable mechanical properties, biodegradability, and biocompatibility. Nonetheless, the clinical application of degradable metallic zinc is largely hindered by the uncontrolled release of Zn²⁺ from the substrate. Herein, a hybrid zinc oxide-zinc sulfide (Zn@ZOS) film was constructed on Zn substrates using the hydrothermal method to slow down the release rate of Zn²⁺. The water contact angle of Zn@ZOS was found to be greater than that of Zn, indicating an enhancement in hydrophobicity. Additionally, the corrosion rate exhibited a significant reduction. The release of Zn²⁺ in the Zn@ZOS sample decreased by approximately 50% compared with the Zn sample. <i>In vitro</i> experiments have demonstrated that Zn@ZOS exhibits excellent biocompatibility. C3H10T1/2 cells cultured in a 50% Zn@ZOS extract exhibited a cell viability of 110%, significantly surpassing that observed with Zn. Moreover, Zn@ZOS facilitates the osteogenic differentiation of C3H10T1/2 cells, as evidenced by enhanced alkaline phosphatase (ALP) activity, increased extracellular matrix (ECM) mineralization, and upregulated expression of osteogenic genes, including Bone Morphogenetic Protein 2 (<i>Bmp2</i>), Collagen type I (<i>Col-I</i>), and Runt-related transcription factor 2 (<i>Runx2</i>). Furthermore, a rat femur implantation model proved that Zn@ZOS implants showed superior bone regeneration <i>in vivo</i> than uncoated Zn. In conclusion, Zn@ZOS exhibits significant potential as an innovative biodegradable metallic material for future orthopedic applications.