Rationally Engineered AZ31–45S5 Bioglass Biocomposites with Superior Biological, Mechanical, and Corrosion Properties for Biodegradable Bone Implants

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Magnesium (Mg)-based biodegradable materials have attracted considerable attention for temporary orthopedic implants owing to their favorable mechanical properties and biodegradability. However, the rapid corrosion of Mg alloys under physiological conditions limits their clinical application. In this study, AZ31–45S5 bioglass (BG) composites containing 5, 10, 15, and 20 wt.% BG were successfully fabricated by powder metallurgy through cold compaction followed by sintering at 500°C. The effects of BG reinforcement on the structural, mechanical, corrosion, bioactivity, cytocompatibility, and antibacterial properties of the composites were systematically investigated. The incorporation of BG improved the density and Vickers microhardness of the composites, while AZBG-15 exhibited the most balanced combination of physical and mechanical properties . X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field-emission scanning electron microscopy (FESEM), and Energy-dispersive spectroscopy (EDS) confirmed progressive hydroxyapatite (HAp) formation after immersion in simulated body fluid for 1, 7, 14, and 21 days , demonstrating enhanced in vitro bioactivity with increasing BG content. Electrochemical polarization and impedance spectroscopy revealed improved corrosion resistance of the BG-reinforced composites compared with the unreinforced AZ31 alloy owing to the formation of a stable protective surface layer. The composites also exhibited excellent MC3T3-E1 pre-osteoblast cytocompatibility and effective antibacterial activity against Escherichia coli and Staphylococcus aureus . Among all compositions, AZBG-15 demonstrated the optimum overall performance by providing the best balance of mechanical integrity, corrosion resistance, bioactivity, cytocompatibility, and antibacterial efficacy , highlighting its potential as a promising biodegradable material for temporary orthopedic implant applications.