Walnut Shell-Porogen HA-MgO Porous Scaffolds for Bone Regeneration

The regeneration of bone defects remains a significant clinical challenge in orthopedic and reconstructive medicine. Conventional approaches, such as autografts and allografts, often prove insufficient in addressing the multifaceted biological and mechanical demands essential for successful bone regeneration. Therefore, the design and development of bioactive porous scaffolds with improved regenerative potential have emerged as a critical focus of current research. In this study, a hydroxyapatite (HA)-based scaffold, commonly employed in bone regeneration, was innovatively engineered by incorporating magnesium oxide (MgO) and utilizing walnut shells as a natural pore-forming agent through high-temperature sintering. By adjusting the content ratios of MgO and walnut shells, HA-MgO porous bone tissue engineering scaffolds with varying proportions were successfully fabricated. The HA–2% MgO scaffold fabricated with a 50% walnut shell ratio demonstrated a well-defined porous architecture and compressive strength closely resembling that of human cancellous bone. In vitro evaluations further revealed improved biological performance, characterized by increased cell adhesion, proliferation, and migration, as well as significant osteogenic differentiation. These findings provide preliminary evidence that the synergistic presence of Ca 2+ and Mg 2+ ions can effectively stimulate bone regeneration, providing a strategic foundation for the rational design of next-generation HA-magnesium composite scaffolds.