Abstract

Despite significant advancements in traditional bone repair bioceramics, developing materials with inherent osteoinductive capabilities remains a challenge, highlighting the need for innovative biomaterials that actively promote osteogenesis. In this study, aluminophosphate (SAPO) zeolites with nanometric dimensions were hydrothermally synthesized, structurally tailored, and characterized to develop osteoinductive properties. Their in vitro bioactivity was evaluated through assays of apatite mineralization, degradation, ion release, protein adsorption, cell adhesion, viability, and osteogenic differentiation using pre-osteoblast cells. SAPO-34 and SAPO-5 crystals, engineered with nanosheet-like morphologies and sub-nanometer nanoporous topologies, incorporated calcium and lithium cations into intra- (CaSAPO, LiSAPO) and extraframework (Ca/ CaSAPO, Li/LiSAPO) positions while preserving their crystalline nanoporous structure. These zeolites promoted apatite formation within 14 days, driven by their high surface area, optimized surface chemistry, and the presence of calcium as extraframework cations. SAPO zeolites exhibited a degree of degradation (5-22 wt. %) under simulated physiological conditions, accompanied by the sustained release of Li+ and Ca2+ ions. Cytocompatibility studies confirmed pre-osteoblast viability and adhesion up to 250 mu g/mL over 14 days, with Ca/CaSAPO and Li/LiSAPO forms showing enhanced biocompatibility. The nanosized SAPO particles stimulated osteogenic cell differentiation in the absence of osteogenic supplements, driven not only by the release of bioactive ions but also by their intrinsic physical and chemical characteristics, including their nanoporous structure and surface composition. These findings identify SAPO zeolites, particularly those modified with lithium and calcium, as promising candidates for bone regeneration. Future in vivo studies are recommended to evaluate their integration into scaffolds and applications in orthopedic and regenerative medicine.