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

Abstract

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 a 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 (GO) nanostructures (GO-An-Zn) on the pure Zn substrates via anodic oxidation followed by silk fibroin/GO 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 (Dex)-laden hierarchical microstructured/nanostructured Zn (GO-Dex-An-Zn) show the enhanced cell compatibility and osteogenicity, outperforming these on pure Zn substrates. It is mainly attributed to the synergistic delivery of Zn ions and Dex from bulk materials during degradation, forming a favorable microenvironment for cell survival and bone tissue remodeling. Accordingly, such work provides a novel solution to simultaneously improve the bactericidal activity and osteogenic potential of Zn-based biomaterials, bode well for their orthopedic use.

<p>Applications of Graphene and Its Derivatives in Bone Repair: Advantages for Promoting Bone Formation and Providing Real-Time Detection, Challenges and Future Prospects</p>

“…GDs could be introduced into different kinds of substrates, such as metals, [130][131][132] inorganic nonmetals, [133][134][135][136] natural polymers [137][138][139] and synthetic polymers [140][141][142][143] to prepare bone repair materials with improved performance, as shown in Table 3. In this subsection, the updated progress on research and development of those materials was reviewed.…”

“…GDs played a very important role in the preparation and development of load-bearing bone materials with excellent functions. [130][131][132] Metal substrate provided hard mechanical support for load-bearing bone materials, but it also had the problems of fast corrosion rate, stress shielding and low bioactivity. Therefore, GDs with the excellent properties were used to improve the in vitro/in vivo function of the composites, and the synergistic effect of GDs and substrate provided a good microenvironment for further improving the performances of the composites.…”

“…In another case, Lyu et al 131 constructed layered ZnO nanotubes/silk fibroin/graphene oxide nanostructures (SF/GO-ZnO) on pure zinc substrates by anodizing and SF/GO selfassembly. Subsequently, SF/GO-Dex-ZnO was prepared by coating the osteogenic drug dexamethasone (Dex) to further improve the function of the composites.…”

A review on current research status of the surface modification of Zn-based biodegradable metals

“…Gilani et al [ 206 ] constructed ZnO micro/nano hole array and nanopariticle array on Zn foil by anodic oxidation and demonstrated superior antibacterial property against both Gram-negative E. coli and Gram-positive S. aureus . Besides, Lyu et al [ 207 ] fabricated dexamethasone-laden ZnO nanotube on Zn substrate by anodic oxidation followed by silk fibroin/graphene self-assembly. They found that this composite coating enhanced the biocompatibility and antibacterial property due to the synergistic release of Zn ions and drug during degradation.…”

3D‐Printed Titanium Cage with PVA‐Vancomycin Coating Prevents Surgical Site Infections (SSIs)

“…A large number of researches focus on the construction of antimicrobial coating on the surface of implant including electrochemical coating, antibiotic‐carrying polymer coating, silver‐carrying ion coating, surface antimicrobial peptide anchoring, anodic oxidation etc. [ 6–9 ] In addition, there are some studies focusing on the strategy of antibacterial modification for interbody fusion polyetheretherketone cages, such as layer‐by‐layer self‐assembly and dip‐coating methods. [ 10–11 ] However, there is few researches focused on the antibacterial modification for interbody fusion titanium (Ti) cages.…”