Chondrogenic Differentiation Of Human Bone Marrow Mesenchymal Stem Cells On Polyhydroxyalkanoate (PHA) Scaffolds Coated With PHA Granule Binding Protein Phap Fused With RGD Peptide

In this research, Poly(3-hydrox-ybutyrate-co-3-hydroxyhexanoate) (PHBHHx) were coated with a fusion protein PhaP (PHA granule binding protein) fused with RGD peptide (PhaP-RGD).Human bone marrow mesenchymal stem cells (hBMSCs) were seeded on the scaffolds for formation of articular cartilages from chondrogenic differentiation of hBMSCs. Immerging in serum minus chondrogenic induction medium, PhaP-RGD coating led to more homogeneous spread of cells, better cell adhesion, proliferation and chondrogenic differentiation in the scaffolds compared with the control group which are PhaP coated or uncoated scaffolds. In addition, more extracellular matrices were produced by the differentiated cells on the PhaP-RGD coated scaffolds evidenced by scanning electron microscopy imaging, enhanced expression of chondrocyte specific genes including sox-9, aggrecan and Type II collagen. Furthermore, level of cartilage-specific extracellular substances, sulphated glycosaminoglycans (sGAG) on the PhaP-RGD coated scaffolds were significantly higher compared with that on the uncoated and PhaP coated scaffolds. Homogeneously distributed chondrocytes-like cells forming cartilage-like matrices were observed on the PhaP-RGD coated scaffolds after 3 weeks. The results suggested that PhaP-RGD coated PHBHHx scaffolds promoted chondrogenic differentiation of hBMSCs and could support cartilage tissue engineering.