为改进目前制备组织工程支架存在孔洞贯通性差或需要盐析法除去致孔剂、负载的生长因子容易失活，同时无法获得粗糙表面等缺点，本项目拟采用超临界二氧化碳流体相转化技术，以碳酸氢铵颗粒和薄荷醇为双重致孔剂，制备由多孔纳米纤维构建的三维支架。通过工艺参数优化，制备出孔径可控、大孔和微孔共存、孔隙率高、孔洞相互贯通、由多孔纳米纤维形成的三维支架。然后考察支架微观纳米拓扑结构对细胞活性变化、黏附聚集状况、细胞增殖、细胞迁移的影响，测定细胞分泌蛋白总量及特定蛋白表达水平，并进行组织学及免疫组化鉴定；考察不同微观纳米拓扑结构支架中粘附的血清蛋白种类及数量、支架中细胞的面积、细胞的骨架发育情况以及TGF-β1/MMPs信号通路情况，探讨支架结构与细胞相互作用的机理。最后考察负载生长因子-海藻酸钠/壳聚糖微胶囊的复合支架对生长因子的缓释、保护作用及生长因子对支架中细胞生长的促进作用，并对支架材料的降解性进行研究。

The limits of traditional techniques used to produce tissue engineering scaffolds include poor interconnected pores or using the salt leaching process for removal of solid porogen, easy deactivation of the loaded growth factors and difficulty in obtaining rough surface. In this project, a porous-nanofibers-based three-dimensional tissue engineering scaffold with porous nanofibrous structure is prepared by the phase inversion by supercritical CO2 technology using the ammonium bicarbonate particles and menthol as dual porogens. By optimizing the operating parameters, it is expected to obtain a three-dimensional scaffold with porous nanofibrous structure, which possesses both large pores and micropores with a controllable pore size, high porosity, and interconnected structure. Then the studies on the effects of nanotopography of scaffold on cells will be carried out; including the measurements of cell viability, cell adhesion and aggregation ability, cell proliferation and cell migration, total protein secretion and expression of specific protein, histological and immunohistochemical identification, the type and number of serum protein, cell area, cell skeleton development and signal pathway of TGF-β1/MMPs in the scaffold with different nanotopography characteristics, the mechanism of scaffold interacts with cells will be studied. Finally, the sustained release and protection properties of the composite scaffolds incorporated with growth factor loaded alginate/chitosan microcapsules will be investigated; the effects of growth factor in the scaffold on the cell growth, and the degradation profiles of the scaffold materials will also be studied.