An electrospun PGS/PU fibrous scaffold to support and promote endothelial differentiation of mesenchymal stem cells under dynamic culture condition

Shear stress is one of the dominant mechanical stimuli present in a vessel wall and an important regulator of endothelial cells functions. It has been shown that shear stress can derive endothelial differentiation of mesenchymal stem cells (MSCs). Engineering a vascular basement membrane thus requires a scaffold that is not only biocompatible but also able to withstand shear stress and support endothelial differentiation of MSCs in the presence of shear stress. In this study, we fabricated an electrospun poly(glycerol sebacate) (PGS)/polyurethane (PU) fibrous scaffold and characterized its physical properties, mechanical properties, and platelet adhesion and hemolysis induction. The developed PGS/PU indicated desirable hydrophilicity (∼41°), an elastic modulus (∼27 MPa) close to that of the Saphenous vein, and no significant level of hemolysis (∼0.03%) and platelet adhesion. The PGS/PU was next seeded with MSCs and implemented in a custom-made bioreactor for applying shear stress (magnitude: ∼15 dyn/cm2, duration: 24 h). Investigating the endothelial-specific gene expression in the presence of shear stress revealed that expression levels of VEGF R-2, VWF, and PCAM-1 significantly increased for the cells seeded on the PGS/PU scaffold compared to those seeded on a glass coverslip. It is thereby concluded that the developed PGS/PU fibrous scaffold can support and significantly promote the endothelial differentiation of MSCs in the presence of shear stress without the need for any growth factors. The findings of this study could provide insights into engineering a functional vascular basement membrane in vitro for vascular tissue engineering applications.