Muti-interactions based 3D-printed osteochondral biomimetic scaffold for BMP-2 sustained release

Osteochondral defects pose significant challenges in tissue regeneration due to the complex structure and composition of native tissue. Restoring the intricate structure and functional capacity of tissues remains a formidable task in osteochondral transplantation. In this study, a novel composite crosslinked 3D printing ink was designed to construct a biomimetic osteochondral scaffold with a sustained release bone morphogenetic protein 2 (BMP-2) hydrogel system of dopamine-modified hyaluronic acid (HAD) and BMP-2 interaction. The enzyme-linked immunosorbent assay results showed a cumulative release of BMP-2 reaching 48.3 %±6.1 % at 28 days. Theoretical calculations indicated that the binding affinity of HAD and BMP-2 was −41.8 ± 1.27 kJ/mol. These findings corroborated the outstanding sustained release efficacy of the hydrogel scaffolds due to the HAD and BMP-2 interaction. Biological function evaluations revealed that the scaffolds possessed significant osteogenesis and chondrogenesis abilities in vitro . This effect is attributed to the hydrophilic nature of the upper layer of the scaffold and the sustained release of BMP-2 from the lower layer. Ultimately, the bilayer scaffolds achieved integrated osteochondral regeneration in a rat model. These results demonstrated the potential of the 3D-printed biomimetic scaffolds with a sustained release BMP-2 hydrogel system for osteochondral repair.