Enhancing bone regeneration: The role of short fiber reinforced hydrogel with CO2-controlled release on the osteogenic differentiation of bone marrow mesenchymal stem cells.

The utilization of hydrogels in bone defect repair applications faces numerous challenges, while carbon dioxide (CO2) demonstrates potential beneficial effects in bone healing processes. Based on this, the current study proposes a novel approach, namely, the deployment of a hydrogel scaffold laden with CO2-controlled release material to promote bone defect repair, successfully proving its beneficial impact. By combining Poly-L-lactic Acid (PLLA), Gelatin Methacryloyl (GelMA), Nano-Hydroxyapatite (nHA), and Ammonium Bicarbonate (NH₄HCO₃) into a composite material, CO₂ may be produced in a 37°C PBS environment, primarily due to the decomposition of NH₄HCO₃. Additionally, the material can be thermosensitive, and the application of near-infrared (NIR) light may further enhance the CO₂ release by increasing the temperature locally, facilitating the decomposition of NH₄HCO₃. Bone marrow stromal cells (BMSCs) were cultured on the composite hydrogel to evaluate cell proliferation and osteogenic differentiation in vitro, while a rat cranial bone defect model was employed to assess in vivo bone regeneration. The research results indicate that this composite material significantly promotes BMSC cell proliferation and osteogenic differentiation and successfully accelerates bone healing in a rat cranial bone defect model. The substantiated insights and empirical evidence proffered herein lay a robust foundation for subsequent explorations in this vanguard domain of research.