BBPs-functionalized tetrahedral framework nucleic acid hydrogel scaffold captures endogenous BMP-2 to promote bone regeneration.

Abstract

Bone Morphogenetic Protein-2 (BMP-2) is a key growth factor for inducing osteogenic differentiation and promoting bone remodeling. However, the exogenous application of delivery systems for BMP-2 has been hampered by various postoperative complications, poor stability and high price. Hence, in situ enrichment of endogenous BMP-2 is promising. The discovery of a small molecule BMP-2 binding peptide (BBP) that binds specifically to BMP-2 with high affinity lays the foundation for the construction of bioactive materials that capture endogenous BMP-2. In contrast, conventional enrichment strategies have low binding efficiency due to steric hindrance caused by the disordered arrangement of BBPs. Tetrahedral framework nucleic acid (tFNA) exhibits good editability and unique three-dimensional spatial structure that enables topological control of multivalent ligands in spatial distribution. The BBPs are further designed to be stably modified on tFNA (BBPs-tFNA) via click chemistry of the azide-alkyne addition to achieve the orderly arrangement of BBPs in spatial organization, to improve the binding efficiency of BMP-2. Therefore, in this study, BBPs-tFNA is modified on biocompatible hyaluronic acid methacryloyl (HAMA) to construct the functionalized bioactive composite hydrogel scaffolds, with the aim of achieving precise and efficient capture of endogenous BMP-2, stimulating osteogenic differentiation and promoting in situ osteogenesis for bone defect repair.