Preparation of Ag@3D-TiO Scaffolds and Determination of its Antimicrobial Properties and Osteogenesis-promoting Ability.

Objectives: The micro-nano structure of 3D-printed porous titanium (Ti) alloy with excellent performance in avoiding stress shielding and promoting bone tissue differentiation provides a new opportunity for the development of bone implants, but it necessitates higher requirements for bone tissue differentiation and the antibacterial properties of bone implants in clinical practice.

Methods: This study investigated the preparation, antimicrobial properties, and osteogenesis-promoting ability of the 3D printed porous Ti alloy anodic oxidized Ag-carrying (Ag@3D-TiO) scaffolds. The 3D printed porous Ti alloy (3D-Ti), anodized 3D printed porous Ti alloy (3D-TiO), and Ag@3D-TiO scaffolds were synthesized using electron beam melting. The antimicrobial properties of the scaffolds were examined using antibacterial tests and their cytocompatibility was assessed using a cell proliferation assay and acridine orange/ethidium bromide (AO/EB) staining. In vitro cellular assays were used to investigate the effects of the scaffold microstructural features on cell activity, proliferation, and osteogenesis-related genes and proteins. In vivo animal experiments were used to evaluate the anti-inflammatory and osteogenesis-promoting abilities of the scaffolds.

Results: The Ag@3D-TiO scaffolds exhibited sustained anti-microbial activity over time, enhanced cell proliferation, facilitated osteogenic differentiation, and increased extracellular matrix mineralization. In addition, alkaline phosphatase (ALP), collagen type I (COL-I), and osteocalcin (OCN)-related genes and proteins were upregulated. In vivo animal implantation experiments, the anti-inflammatory effect of the Ag@3D-TiO scaffolds were observed using histology, and a large amount of fibrous connective tissue was present around it; the Ag@3D-TiO scaffolds were more bio-compatible with the surrounding tissues compared with 3D-Ti and 3D-TiO; a large amount of uniformly distributed neoplastic bone tissue existed in their pores, and the chronic systemic toxicity test showed that the 3D-Ti, 3D-TiO, and Ag@3D-TiO scaffolds are biologically safe.

Conclusion: The goal of this study was to create a scaffold that exhibits antimicrobial properties and can aid bone growth, making it highly suitable for use in bone tissue engineering.