Porous ZnO/Zn scaffolds fabricated using binder-jetting 3D printing promote bone regeneration: in vitro and in vivo evidence.

Abstract

Additive manufacturing offers an effective approach for fabricating biodegradable porous scaffolds that can adapt to the mechanical properties of jawbones. Zinc (Zn) and its alloys are considered promising degradable materials due to their appropriate degradation rates, favorable mechanical properties, and diverse biological functionalities. Zinc oxide (ZnO) has been shown to promote the growth of vascular endothelial cells and significantly enhance the vascularization ability of implant materials. In this study, a porous ZnO/Zn scaffold with a triply periodic minimal surface (TPMS) structure and ∼75% porosity was fabricated via binder-jetting 3D printing and subsequently sintered at 800, 900, 1000, and 1100°C. The sintered scaffold was systematically evaluated for its microstructure, mechanical properties, corrosion resistance, and biological properties both in vitro and in vivo. The results demonstrated that the porous ZnO/Zn scaffold contained α-Zn and ZnO phases, and with increasing sintering temperature, the α-Zn phase gradually transformed into ZnO, leading to a progressive decrease in degradation rate and Zn²⁺ release. The sintered scaffold exhibited compressive strength comparable to cancellous bone, good cytocompatibility, enhanced osteogenic and angiogenic potential in vitro, and measurable antibacterial properties. Furthermore, the scaffold effectively promoted bone integration in vivo, suggesting its potential for the repair of oral and maxillofacial bone defects, although further studies and clinical validation are required. STATEMENT OF SIGNIFICANCE: This work reports the successful fabrication and comprehensive evaluation of a porous ZnO/Zn scaffold featuring a triply periodic minimal surface (TPMS) structure, fabricated via binder-jetting 3D printing technology, for next-generation maxillofacial bone-defect repair. Our findings demonstrated that the 75% porosity scaffold exhibits compressive strength comparable to human cancellous bone, satisfying the mechanical requirements for jawbone applications. The scaffold integrates robust biocompatibility with multifunctional bioactivity, as its composition potently promotes osteoblast viability, enhances vascular endothelial cell growth, and stimulates osteogenic differentiation in vitro. Critically, the scaffold demonstrates notable in vitro antibacterial properties and effectively promotes bone integration in vivo, positioning it as a promising degradable implant with tailored mechanical adaptation and enhanced vascularization capability for maxillofacial reconstruction.