Study on the bone morphogenetic protein 2 loaded synergistic hierarchical porous silk/carbon nanocage scaffold for the repair of bone defect

Abstract

Bone morphogenic protein-2 (BMP2) as an outstanding growth factor has a dominant role in the new bone formation, which still leaves much room for efficiency improvements to its clinical application owning to the potential side effects with high dosage. In this study, carbon nanocages (CNCs) were firstly considered as a synergistic factor for BMP2. CNC could improve the osteogenesis of BMP2 (0.8 μg/mL) at a concentration of 20–80 μg/mL in a dose-dependent manner. Moreover, a composite hierarchical porous scaffold composed of silk fibroin (SF) and CNC (SF/CNC) was developed for the controlled delivery of BMP2, which provided delivery of BMP2 with an initial burst release of 23.9% and a gradual release over the subsequent 6 days to about 47.7%. According to the ALP staining and quantification, CNC and SF/CNC scaffold (without BMP2) were evidenced to promote osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) dose-dependently. After loading BMP2, BMP2/SF/CNC scaffold could significantly increase the osteogenic differentiation of BMSCs in vitro and promote new bone formation in vivo. BMP2/SF/CNC scaffold developed in this study could efficiently prolong the local retention of BMP2 and its synergic interaction duration with CNC, which provides a new strategy for bone tissue engineering.