Biofunctionalization of WE43 Mg Scaffolds with Calcium-Based Bioactive Ceramics for Enhanced Bone Regeneration

• A comprehensive comparison of bioceramic reinforcements (Wollastonite, Akermanite, Harystonite) revealed distinct effects on corrosion and biological response. • Mg/Wollastonite and Mg/Akermanite composites exhibited outstanding osteoblast adhesion, viability, and ALP activity compared to unreinforced Mg. • Incorporating bioceramics significantly reduced hydrogen evolution and Mg²⁺ ion release, enhancing long-term biocompatibility. • Multi-pass FSP achieved profound grain refinement in Mg matrix, leading to superior bioactivity. Magnesium metallic biomaterials, being biocompatible and bioabsorbable, are potential candidates for temporary orthopedic implants. However, their use is limited by the challenge of simultaneously achieving the optimum biodegradation rate, mechanical strength, and biological performance during healing. This present study aims to address these challenges by incorporating Ca-based bioceramic reinforcements and microstructural modification via friction stir processing (FSP). In the present study, wollastonite (CaSiO₃), akermanite (Ca₂MgSi₂O₇) and hardystonite (Ca₂ZnSi₂O₇) powders were incorporated into a WE43-T6 Mg alloy matrix using multi-pass FSP to achieve bioactive Mg-based composites. Scanning electron microscopy (SEM) observation revealed that six FSP passes led to extensive grain refinement of the Mg matrix, and uniform dispersion of bioceramic reinforcements. These microstructural improvement and homogeneity of bioceramic particles significantly reduced biodegradation rate and results in formation compact protective layer on surface. The release of Ca²⁺, Si 2+ and Zn 2+ ions from the bioceramic phases improved biocompatibility and osteogenic activity, evidenced by enhanced cell attachment, cell viability, and alkaline phosphate (ALP) activity of MC3T3-E1 pre-osteoblast cells. Moreover, the optimized composite microstructure effectively controlled hydrogen evolution during degradation to exhibit more stable and predictable bioabsorption behavior. In conclusion, the combination of multi-pass FSP processing and Ca-based bioceramic reinforcement triggered a synergistic intensification of structural stability and biofunctionality, validating that the resulting Mg-based biocomposites possess the required characteristics to guarantee safe and effective temporary orthopedic implant applications.