Nanocomposite Bone Scaffolds Based on Magnesium Alloy: A Detailed Investigation of Their In-Vitro Biodegradation...

Polymeric biomaterials and their composites have been extensively explored for orthopaedic applications; however, their inadequate mechanical performance significantly restricts their use in load-bearing environments. Metallic biomaterials, by contrast, offer superior mechanical strength and structural stability. Among them, magnesium (Mg) has emerged as a particularly attractive candidate for temporary orthopaedic implants owing to its elastic modulus and density being close to those of natural bone, thereby minimising stress shielding. In addition, Mg inherently fulfils two critical requirements for orthopaedic implants-biocompatibility and biodegradability. In this study, a bioactive magnesium-alloy-based nanocomposite scaffold was engineered to overcome the limitations of conventional biomaterials while closely replicating the porous microarchitecture of human bone. A novel bioactive glass-ceramic, nano-fluorcanasite (n-FC), was incorporated into the Mg-alloy matrix to enhance osteogenic activity and accelerate bone tissue regeneration. The introduction of an interconnected porous structure was designed to promote efficient nutrient diffusion, facilitate metabolic waste removal and reduce implant density. Furthermore, the controlled addition of selected alloying elements in specific weight fractions effectively moderated the degradation kinetics of the Mg-based scaffold. The nanocomposite scaffolds were fabricated using a powder metallurgy route followed by sintering. Tailored porosity was achieved through the controlled incorporation of carbamide particles as a space-holding agent. The in vitro degradation behaviour of the scaffolds was systematically evaluated using a weight-change method after immersion in phosphate-buffered saline (PBS) for predetermined durations. The results demonstrate that, compared with unalloyed magnesium, the degradation rate of the nanocomposite scaffolds can be precisely and consistently regulated, highlighting their potential as mechanically competent, bioactive and biodegradable candidates for orthopaedic implant applications.