Bioactive scaffolds harnessing ionic modifications to promote osteogenesis and angiogenesis in bone regeneration

This study proposes the modification of multilayer scaffolds based on the SiO₂–CaO–P₂O₅ system by incorporating bioactive ions, such as magnesium or lithium, with the aim of enhancing the cellular processes involved in bone regeneration. Two types of scaffolds, CS04 and CS05, were prepared, varying the amount of MgO (0.38; 0.49% w/w). The prepared scaffolds exhibited an interconnected porous structure, with SiO₂, Ca₂P₂O₇ and β-Ca₃(PO₄)₂ as predominant crystalline phases, a compressive strength of 1.8 MPa and a porosity above 75%. Bioactivity tests demonstrated that minor variations in the amount of MgO altered the surface topography and bioactive behaviour, resulting in a lamellar microstructure (CS04) and precipitation of hollow HA spheres (CS05). From a biological point of view, the scaffolds proved to be biocompatible, as were their dissolution products at 10 and 100 mg/mL. Both promoted MC3T3-E1 cell proliferation, calcium deposition and osteoblastic differentiation, as reflected by increased ALP activity. In addition, they induced VEGF release in MC3T3-E1, thereby demonstrating their angiogenic potential. Taken together, these results suggest that the scaffolds possess optimal properties for bone regeneration applications.