Bolstered bone regeneration by multiscale customized magnesium scaffolds with hierarchical structures and tempered degradation

Addressing irregular bone defects is a formidable clinical challenge, as traditional scaffolds frequently fail to meet the complex requirements of bone regeneration, resulting in suboptimal healing. This study introduces a novel 3D-printed magnesium scaffold with hierarchical structure (macro-, meso-, and nano-scales) and tempered degradation (microscale), intricately customized at multiple scales to bolster bone regeneration according to patient-specific needs. For the hierarchical structure, at the macroscale, it can feature anatomic geometries for seamless integration with the bone defect; The mesoscale pores are devised with optimized curvature and size, providing an adequate mechanical response as well as promoting cellular proliferation and vascularization, essential for natural bone mimicry; The nanoscale textured surface is enriched with a layered double hydroxide membrane, augmenting bioactivity and osteointegration. Moreover, microscale enhancements involve a dual-layer coating of high-temperature oxidized film and hydrotalcite, offering a robust shield against fast degradation. Eventually, this scaffold demonstrates superior geometrical characteristics, load-bearing capacity, and degradation performance, significantly outperforming traditional scaffolds based on in vitro and in vivo assessments, marking a breakthrough in repairing customized bone defects.