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.