In situ activation of bone marrow stem cells by a hemostatic alginate/laponite/eggshell nanocomposite sponge for alveolar bone regeneration

Post-extraction hemorrhage and alveolar bone loss remain critical challenges following tooth extraction, necessitating biomaterials that can simultaneously control bleeding and promote bone regeneration. In this study, we developed an alginate-based nanocomposite sponge reinforced with a nanofiberized eggshell membrane arranged in a sandwich-like structure, designed to deliver dual hemostatic and osteogenic functions. The engineered sponge demonstrated rapid swelling, favorable gelation, biodegradability, and biocompatibility, without stimulating adverse immune responses. Hemocompatibility tests revealed efficient hemostatic performance, with a blood clotting index of ∼7%, red blood cell adhesion of ∼80%, and platelet aggregation of ∼90%, leading to rapid and stable clot formation. The presence of a clot alongside structural bioactive components provided a biologically favorable scaffold for bone marrow stem cells (BMSCs), significantly enhancing osteogenic differentiation. In vitro results confirmed elevated expression of RUNX2 and osteocalcin (OCN), alongside higher alkaline phosphatase activity and robust mineralized matrix deposition in BMSCs cultured with the composite. In vivo, a rat mandibular extraction model demonstrated nearly a two-fold reduction in bleeding time and blood loss, as well as substantial alveolar bone regeneration within 60 days, verified through CBCT imaging and histopathological analysis (p < 0.0001). Collectively, this dual-functional nanocomposite sponge represents a promising biomaterial for accelerating hemostasis and supporting post-extraction bone healing.