BMP-2 immobilized PLGA/hydroxyapatite fibrous scaffold via polydopamine stimulates osteoblast growth

Combining biomaterials scaffolds with bone morphogenetic protein-2 (BMP-2) is currently used to promote the regeneration of bone tissue. However, the traditional strategies used to add BMP-2 into the polymer scaffolds directly suffer from limitations that can result in lower growth factor loading and damage the bioactivity of growth factors. In this study, we report the fabrication of poly(lactide-co-glycolide)/hydroxyapatite (PLGA/HA) composite fibrous scaffolds via melt-spinning method to mimic native extracellular matrix (ECM). In order to effectively immobilize BMP-2 on PLGA/HA composite fibrous scaffolds, the surface of the scaffold was modified with polydopamine (PDA) (PDA-PLGA/HA). PDA was chosen as an adhesive polymeric bridge-layer between PLGA/HA fibrous scaffolds and BMP-2. Analysis of the scaffold using scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscope revealed that the PDA coating was attached to the scaffold surface. Moreover, analysis of the scaffold using water contact angle demonstrated an increased hydrophilicity via PDA modification. Furthermore, the PDA coating effectively immobilized BMP-2 on the PDA-PLGA/HA fibrous scaffold and a sustained release profile of BMP-2 was achieved in the BMP-2-immobilized PLGA/HA fibrous scaffold. In vitro experiments showed that BMP-2-immobilized PLGA/HA fibrous scaffold significantly promoted the attachment and proliferation of MC3T3-E1 cells. More importantly, the ALP activity, mRNA expression of osteosis-related genes and calcium deposition in MC3T3-E1 cells cultured on BMP-2-immobilized PLGA/HA fibrous scaffold were significantly increased. These results collectively demonstrate that the BMP-2-immobilized PLGA/HA fibrous scaffold is a promising candidate for bone regeneration.