Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) scaffolds coated with PhaP-RGD fusion protein promotes the proliferation and chondrogenic differentiation of human umbilical cord mesenchymal stem cells in vitro

Human umbilical cord blood-derived mesenchymal stem cells (hUC-MSCs) have been widely used in tissue engineering. The aim of this study is to evaluate the ability of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) scaffolds coated with polyhydroxyalkanoate binding protein fused with arginyl-glycyl-aspartic acid (PhaP-RGD) to promote the proliferation and chondrogenic differentiation of hUC-MSCs seeded on them. The PhaP-RGD fusion protein was expressed by Escherichia coli. PHBHHx films were coated with PhaP-RGD fusion protein and the physiochemical properties were examined. hUC-MSCs were seeded on PHBHHx films with or without PhaP-RGD precoating and tested for changes in morphology, viability, and chondrogenic differentiation. We found that PhaP-RGD-coated PHBHHx films had similar surface morphology to uncoated PHBHHx. The water contact angle of the coated PHBHHx surface was lower than that of the uncoated surface (10.63 degrees vs. 98.69 degrees). At 7 and 14 days after seeding, the PhaP-RGD-coated PHBHHx group showed greater numbers of viable cells compared to the uncoated PHBHHx group. The expression levels of aggrecan and collagen II were enhanced in the PhaP-RGD-coated PHBHHx group relative to the uncoated PHBHHx group. Histological analysis using toluidine blue staining showed elevated formation of proteoglycan producing chondrocytes in the PhaP-RGD-coated PHBHHx group. Additionally, the synthesis of proteoglycan and collagen was significantly enhanced within the PhaP-RGD constructs. Taken together, PhaP-RGD coating promotes the proliferation and chondrogenic differentiation of hUC-MSCs seeded on PHBHHx films. PhaP-RGD-coated PHBHHx may be a useful scaffold for cartilage tissue engineering. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1169-1175, 2015.