Unveiling the synergistic potential: Surface topology and osteogenic elements in biodegradable Zn alloys

Abstract

The topological structure of material surfaces plays a crucial role in cell behavior and tissue regeneration. Current research and applications concerning topological structures for tissue repair predominantly revolve around polymer materials and traditional inert metals. To expand the application of topological structures in the field of biomaterials, this study employed laser etching to create four different topological structures – groove, grid, triangle, and star – on the surface of a biodegradable Zn-0.4Li alloy. In this study, we investigated the effects of different topological structures on the degradation and antibacterial properties of alloys, as well as their influence on cellular behavior and function when synergistically interacting with osteogenic active elements. Our results demonstrated that the presence of micro-nano composite topological structures has significantly altered the physicochemical properties of the material surface. Additionally, laser treatment and the increase in surface roughness resulted in the release of a higher Zn ion concentration. On the one hand, the material's antibacterial performance was enhanced under the combined action of the micro-nano composite on the surface inhibiting bacterial adhesion and the bactericidal effect of zinc ions. On the other hand, excessive zinc ions may cause the concern of cell viability decrease. The tolerance of cells to zinc ions was improved by adding osteogenic elements Ca²⁺ and Sr²⁺. The synergistic effect of micro-nano composite topological structures and osteogenic elements promoted cell adhesion and osteogenic differentiation, and induced cell orientation. The biocompatibility of the material has been significantly improved, enabling the material to be applied to tissue repair and regeneration.