Efficacy of Bone Morphogenetic Protein-2 Peptide-Modified Nano-Hydroxyapatite Alginate Hydrogel in Vertebral Bone Defect Repair.

For the effective treatment of vertebral bone defects (BDs), the authors constructed an innovative hydroxyapatite (HAP) nanoparticle-hyaluronic acid (HA)-alginate (ALG) scaffold loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2). The particle size of HAP was around 80 to 100 nm, and its addition markedly reduced the swelling rate and degradability of the HA-ALG scaffold while enhancing its compression resistance, enabling it to better support the BD site and provide a good proliferation environment for osteoblasts. Furthermore, HAP-HA-ALG effectively extended the half-life of rhBMP-2 by nearly 50-fold, allowing it to exert its osteogenic effects more consistently. In cellular experiments, the authors found that rhBMP-2@HAP-HA-ALG significantly enhanced the activity and migration ability of bone marrow mesenchymal stromal cells, as well as the expression level of related osteogenic proteins in cells, which better exerted osteoinductive and osteoconductive functions. In animal tests, rhBMP-2@HAP-HA-ALG could better facilitate the generation of new bone and bone trabecula at BD sites and markedly enhance the bone density level, thus shortening the repair time of BDs. Therefore, rhBMP-2@HAP-HA-ALG shows great potential in the restoration of vertebral BDs.