Development of biodegradable Zn-based porous scaffolds with elaborate triply periodic minimal surface structure via Vat photopolymerization-assisted template replacement strategy

Abstract

Herein, a novel strategy, namely Vat photopolymerization-assisted template replacement method was developed to achieve elaborate triply periodic minimal surface structure and different pore sizes in biodegradable Zn-based porous scaffolds. The pore structure, microstructure, phase constitution, degradation properties, mechanical performance, in vitro cytocompatibility and antibacterial activity were systematically investigated. As a result, triply periodic minimal surface structures with different pore sizes were successfully obtained in Zn–1Mg porous scaffolds. The actual porosity closely matched the designed porosity, demonstrating the efficacy of the new strategy in achieving precise pore structures with a difference below 2%. Zn–1Mg scaffolds, designed with a pore size of 780 mm, exhibited a uniaxial compressive strength of 59.95 MPa and an elastic modulus of 3.07 GPa. Furthermore, the mechanical integrity was well-maintained even after 28 days of immersion, attributed to the substantial deposition of calcium-phosphate-rich corrosion products within the porous structure. More importantly, a suitable weight loss rate of about 15% were confirmed after 28 days immersion, indicating a period for total degradation of approximately 13 months based on a linear degradation assumption. Further, the experimental scaffolds demonstrated good cytocompatibility with MC3T3-E1 preblast cells and exhibited significant antibacterial activity against both Staphylococcus aureus and Escherichia coli.

Keywords

• Zinc alloy scaffolds
• Template replacement strategy
• Degradation behavior
• Cytocompatibility
• Antibacterial behavior