血管化是组织工程中的难点，构建功能性动静脉血管系统是组织工程在实际应用中的攻坚课题。本课题组最新研究发现，细胞外基质硬度（Stiffness）对血管内皮祖细胞向动脉-静脉内皮方向分化等生物学行为有重要调控作用。本研究拟合成Stiffness可精确调控的二维PDMS材料和三维PEG水凝胶，模拟体内动脉、静脉内皮细胞基质的硬度微环境，深入研究Stiffness-Ras/RhoA- Notch-EphB4/EphrinB2-VEGF信号通路对内皮祖细胞定向分化的调控机制。在此基础上制备梯度硬度的三维PEG水凝胶开展体内研究，期望形成方向可控的功能动静脉血管网络。本研究可为精确调控内皮祖细胞分化和动-静脉功能血管网络形成提供研究基础，为组织工程血管化研究提供新的思路和研究模型。

Angiogenesis is a key process required for regenerative medicine and complete organ engineering. The establishment of functional vascularization with appropriate arterial-venous differentiation remains a major challenge for the widespread translation of tissue engineering applications into medical practice. Recent studies have revealed that stem cell lineage commitment was sensitive to the biophysical status of the microenvironment. For example, the inherent stiffness of the extracellular matrix has a profound impact on cell morphology, proliferation, and cell fate decision. Therefore, in this study, we attempt to develop a two-dimensional polydimethylsiloxane(PDMS)-based substrate and a three-dimensional polyethyleneglycol(PEG) hydrogel, respectively. These two biomaterials are both capable of simulating the physiologically relevant matrix stiffness of both venous and arterial tissue. The bone marrow derived endothelial progenitor cells(EPCs) will be cultured on substrates of different stiffness. And the variations of expressions of arterial and venous specific markers in EPCs will be evaluated. Furthermore, the PEG hydrogel model will be used in nude mice for the blood vessel formation assay. The expressions of arterial and venous specific markers of new vessels in hydrogels of different stiffness will be measured. The effect of different degrees of substrate stiffness on the arterial-venous differentiation of EPCs and new vessels will be revealed and the underlying mechanism will be explored as well. This work may represent a potential method for regulating arterial-venous differentiation for the fulfilment of diverse functions of the vasculature.