Fabrication of a BMP-2-immobilized porous microsphere modified by heparin for bone tissue engineering

•Porous microspheres (PMS) were successfully fabricated by a fluidic device.•PMS was modified heparin-dopamine and bone morphogenic protein-2 (BMP-2).•BMP-2 immobilized on Hep-PMS has sustained release profiles for 28 days.•BMP-2 immobilized on Hep-PMS induced osteogenic differentiation of MG-63 cells.

The purpose of this study was to fabricate BMP-2-immobilized porous poly(lactide-co-glycolide) (PLGA) microspheres (PMS) modified with heparin for bone regeneration. A fluidic device was used to fabricate PMS and the fabricated PMS was modified with heparin-dopamine (Hep-DOPA). Bone morphogenic protein-2 (BMP-2) was immobilized on the heparinized PMS (Hep-PMS) via electrostatic interactions. Both PMS and modified PMS were characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). MG-63 cell activity on PMS and modified PMS were assessed via alkaline phosphatase (ALP) activity, calcium deposition, and osteocalcin and osteopontin mRNA expression. Immobilized Hep-DOPA and BMP-2 on PMS were demonstrated by XPS analysis. BMP-2-immobilized Hep-PMS provided significantly higher ALP activity, calcium deposition, and osteocalcin and osteopontin mRNA expression compared to PMS alone. These results suggest that BMP-2-immobilized Hep-PMS effectively improves MG-63 cell activity. In conclusion, BMP-2-immobilized Hep-PMS can be used to effectively regenerate bone defects.

Graphical abstractInfographics of the fabrication of BMP-2-immobilized porous PLGA microspheres (PMS) modified with heparin-dopamine (Hep-DOPA) for improving MG-63 cell activity.Figure optionsDownload full-size imageDownload as PowerPoint slide