Micro/Nano‐Structured Metal–Organic/Inorganic Hybrid Coatings on Biodegradable Zn for Osteogenic and Biocompatible Improvement

Abstract Biodegradable Zn‐based metals have recently gained great attention for orthopedic implant applications, due to their attractive attributes in biodegradability, mechanics, and bio‐functionalities. However, Zn‐based metals suffer from excessive Zn 2+ release leading to bio‐incompatibility and insufficient osteogenic properties. Herein, bioactive molecules incorporated zinc phosphate (ZnP) of metal–organic/inorganic hybrid coatings are constructed on Zn surfaces by dip‐coating, targeting a decrease in Zn 2+ release rate and an improvement in biocompatible and osteogenic properties. The bioactive molecules, cysteine, phenylalanine, and bovine serum albumin, are incorporated into inorganic ZnP using a metal–organic/inorganic coordination strategy. As a result, these hybrid coatings are compact, and present different micro/nanostructured surface morphology. The electrochemical and long‐term static immersion results show that the hybrid coatings decrease the corrosion rate of Zn, reduce the Zn 2+ ion release rate, and promote hydroxyapatite deposition. In addition, they promote the proliferation and adhesion of preosteoblast MC3T3‐E1 and rat bone marrow mesenchymal stem cells, and up‐regulate the expression of osteogenesis‐related genes. Such appealing properties can be attributed to the characteristic micro/nanostructured surface morphologies and the presence of the bioactive components. These metal–organic/inorganic hybrid coatings provide a novel avenue to modify the surface of Zn‐based metals for orthopedic implant applications.