Visible UCNPs-magnesium matrix composites for optimizing degradation and improving bone regeneration

Magnesium alloys have attracted significant interest in bone tissue engineering because of their beneficial characteristics. However, their widespread application is still hindered by rapid degradation rates and the challenges associated with real-time monitoring. Given that up-conversion nanoparticles (UCNPs) possess imaging capabilities and that nanofillers can enhance the degradation behavior of these materials, we have utilized UCNPs to develop metal matrix composites. Specifically, we employed powder metallurgy technology to prepare up-conversion nanoparticles/magnesium/zinc composites (UCNPs/Mg/Zn). We systematically studied the mechanical properties, degradation behavior, biocompatibility, osteogenic activity, and degradation monitoring of the composite. In vivo and in vitro degradation studies demonstrated that the composite containing 10 % UCNPs, 86 % Mg, and 4 % Zn (10U-Mg-4Zn) gradually degrades over time, with luminous intensity initially increasing from weak to strong before subsequently diminishing. Furthermore, compared to complexes containing 96 % Mg and 4 % Zn (Mg4Zn), the degradation rate of the 10U-Mg-4Zn complex was significantly reduced, while cytocompatibility improved and osteogenic differentiation of mouse embryonic osteoblasts (MC3T3-E1) was markedly enhanced. Therefore, the 10U-Mg-4Zn composite not only demonstrates good degradation performance and supports bone tissue regeneration but also facilitates the monitoring of material degradation, thereby providing a novel method for material evaluation and a fresh perspective for developing new magnesium matrix composites.