Biodegradable Zn-xY alloys with enhanced osteogenesis and angiogenesis effects for bone implant applications

Abstract

Biodegradable zinc-based alloys have gained significant attention in the biomedical field due to their favorable degradability, but challenges remain in enhancing their mechanical properties and biocompatibility. As promising candidates for bone implant materials, improving osteogenic differentiation, angiogenesis and antibacterial properties is crucial. In this study, Zinc-xYttrium (Zn-xY, x = 0.1, 0.6, 1.0 and 2.0 at.%) alloys were developed, and their mechanical properties, degradation behavior, cytocompatibility, osteogenic activity, angiogenic potential and antibacterial properties were systematically evaluated. Specifically, Zn-2.0Y exhibited the highest mechanical strength, with a tensile strength (UTS) of 230 MPa, yield strength (YS) of 170 MPa, and elongation at break (ER) of approximately 16%. In terms of degradation, Zn-2.0Y demonstrated the slowest degradation rate. Additionally, this alloy significantly enhanced osteogenic differentiation and mineralization of human bone marrow-derived mesenchymal stem cells (hBMSCs) and promoted migration and angiogenic activity in human umbilical vein endothelial cells (HUVECs). Moreover, this alloy demonstrated far better antibacterial properties than pure Zn. In vivo rat femoral implantation studies further confirmed that Zn-2.0Y promoted bone integration. Moreover, the study revealed and validated that Zn-2.0Y enhances osteogenic and angiogenic activities through the PI3K/AKT signaling pathway. These findings highlight Zn-2.0Y as a promising biodegradable material for bone implant applications. STATEMENT OF SIGNIFICANCE: The development of advanced biodegradable bone implant materials is crucial for addressing complex challenges in bone repair. This study investigates Zinc-xYttrium (Zn-xY, x = 0.1, 0.6, 1.0 and 2.0 at.%) alloys, focusing on Zn-2.0Y, which exhibits tensile strength >230 MPa, yield strength ∼170 MPa, and elongation at break ∼16%. The degradation rate of Zn-xY alloys decreases with increasing Y content, with Zn-2.0Y showing the lowest rate of 45 µm/y. In vitro and in vivo studies demonstrate that Zn-2.0Y promotes osteogenesis and angiogenesis by activating the PI3K/AKT signaling pathway. These findings highlight Zn-2.0Y as a promising biodegradable material for bone repair.

Keywords: Angiogenesis; Biodegradable zinc (Zn) alloy; Osteogenesis; PI3K/AKT pathway; Yttrium (Y).