MICROSTRUCTURE AND PROPERTIES OF NANO-FIBROUS PCL-b-PLLA SCAFFOLDS FOR CARTILAGE TISSUE ENGINEERING
MICROSTRUCTURE AND PROPERTIES OF NANO-FIBROUS PCL-b-PLLA SCAFFOLDS FOR CARTILAGE TISSUE ENGINEERING
复制标题
软骨组织工程用纳米纤维 PCL-b-PLLA 支架的微观结构和性能
DOI：
10.22203/ecm.v018a06
复制
发表时间：
2009-07-01
影响因子：
3.1
通讯作者：
Ramakrishna, S.
中科院分区：
文献类型：
--
作者：
He, Liumin;Liu, Bin;Ramakrishna, S.
纳米纤维支架由于具有细胞外基质（ECM）的结构特征，被认为是组织工程中细胞输送的理想载体。在本研究中，半结晶二嵌段共聚物，聚（ε-己内酯）-嵌段-聚（L-丙交酯）（PCL-b-PLLA）的合成，并利用通过热诱导相分离过程制备纳米纤维支架。通过将PCL-b-PLLA/THF均匀溶液淬火至-20 ° C或更低，随后由于PLLA和PCL微晶的存在而进一步凝胶化2小时来产生均匀的纳米纤维网络。然而，随着凝胶化温度的升高，纳米纤维网络之间出现了结状结构以及连续光滑的薄膜。DSC分析表明，PCL链段的结晶被刚性PLLA链段中断，导致在高凝胶化温度下的无定形相。结合TIPS（热诱导相分离）与盐浸出方法，纳米纤维结构和互连的孔结构（直径144 +/- 36 μ m）具有高孔隙率的软骨细胞的体外培养创建。纳米纤维支架表面的比表面积和蛋白质吸附是固体壁支架表面的三倍。在纳米纤维支架上培养的软骨细胞表现出球形软骨细胞样表型，并且比在固体壁支架上培养的软骨细胞分泌更多的软骨样细胞外基质（ECM）。此外，在纳米纤维支架上培养的细胞的蛋白质和DNA含量是在固体壁支架上培养的细胞的1.2-1.4倍。与固体壁支架相比，在纳米纤维支架上诱导了更高水平的II型胶原和聚集蛋白聚糖mRNA的表达。这些发现表明，具有纳米纤维结构的支架可以作为软骨组织工程的上级支架。
Nano-fibrous scaffolds which could potentially mimic the architecture of extracellular matrix (ECM) have been considered a good candidate matrix for cell delivery in tissue engineering applications. In the present study, a semicrystalline diblock copolymer, poly(epsilon-caprolactone)-block-poly(L-lactide) (PCL-b-PLLA), was synthesized and utilized to fabricate nano-fibrous scaffolds via a thermally induced phase separation process. Uniform nano-fibrous networks were created by quenching a PCL-b-PLLA/THF homogenous solution to -20 degrees C or below, followed by further gelation for 2 hours due to the presence of PLLA and PCL microcrystals. However, knot-like structures as well as continuously smooth pellicles appeared among the nanofibrous network with increasing gelation temperature. DSC analysis indicated that the crystallization of PCL segments was interrupted by rigid PLLA segments, resulting in an amorphous phase at high gelation temperatures. Combining TIPS (thermally induced phase separation) with salt-leaching methods, nano-fibrous architecture and interconnected pore structures (144 +/- 36 mu m in diameter) with a high porosity were created for in vitro culture of chondrocytes. Specific surface area and protein adsorption on the surface of the nano-fibrous scaffold were three times higher than on the surface of the solid-walled scaffold. Chondrocytes cultured on the nano-fibrous scaffold exhibited a spherical condrocyte-like phenotype and secreted more cartilage-like extracellular matrix (ECM) than those cultured on the solid-walled scaffold. Moreover, the protein and DNA contents of cells cultured on the nanofibrous scaffold were 1.2-1.4 times higher than those on the solid-walled scaffold. Higher expression levels of collagen II and aggrecan mRNA were induced on the nanofibrous scaffold compared to on the solid-walled scaffold. These findings demonstrated that scaffolds with a nanofibrous architecture could serve as superior scaffolds for cartilage tissue engineering.