Bone Morphogenetic Protein 2-Conjugated Silica Particles Enhanced Early Osteogenic Differentiation of Adipose Stem Cells on the Polycaprolactone Scaffold.

Background: Silica particles (SPs) induce cell proliferation and osteogenic differentiation. We reported that SPs in the scaffold induced early stage osteogenic differentiation. Methods: A polycaprolactone (PCL) scaffold was fabricated with a 10 wt% SPs. The surface of PCL scaffold was coated with a 10 µg/mL collagen solution. Next, the scaffold was conjugated with 2 μM SPs, 2 μg/mL bone morphogenetic protein 2 (BMP2), or 2 μM BMP2-conjugated SPs (BCSPs). Green fluorescent protein-coupled BMP2 was applied to fabricate the scaffold. The fluorescence intensity was analyzed by confocal microscopy. The mRNA levels of the early osteogenic differentiation marker, alkaline phosphatase (ALP), were analyzed by real-time quantitative polymerase chain reaction. Levels of BMP2, RUNX2, ERK1/2, and AKT were assessed by western blotting. Results: ALP mRNA levels were significantly higher in the BCSP-conjugated scaffold than in the other scaffolds. In the early stage of osteogenic differentiation, the protein levels of BMP2, RUNX2, ERK1/2, and AKT in cells were significantly higher in the BCSP-conjugated scaffold than in other scaffolds. Thus, the BCSP composite scaffold induced rapid osteogenic differentiation. Conclusion: These results suggest that BCSP composite can be used to promote early stage osteogenic differentiation and show promise as a material for use in scaffolds for bone regeneration.