Pham Quynh P, Sharma Upma, Mikos Antonios G
Department of Bioengineering, Rice University, MS-142, P.O. Box 1892, Houston, Texas 77251-1892, USA.
Biomacromolecules. 2006 Oct;7(10):2796-805. doi: 10.1021/bm060680j.
The physical and spatial architectural geometries of electrospun scaffolds are important to their application in tissue engineering strategies. In this work, poly(epsilon-caprolactone) microfiber scaffolds with average fiber diameters ranging from 2 to 10 microm were individually electrospun to determine the parameters required for reproducibly fabricating scaffolds. As fiber diameter increased, the average pore size of the scaffolds, as measured by mercury porosimetry, increased (values ranging from 20 to 45 microm), while a constant porosity was observed. To capitalize on both the larger pore sizes of the microfiber layers and the nanoscale dimensions of the nanofiber layers, layered scaffolds were fabricated by sequential electrospinning. These scaffolds consisted of alternating layers of poly(epsilon-caprolactone) microfibers and poly(epsilon-caprolactone) nanofibers. By electrospinning the nanofiber layers for different lengths of time, the thickness of the nanofiber layers could be modulated. Bilayered constructs consisting of microfiber scaffolds with varying thicknesses of nanofibers on top were generated and evaluated for their potential to affect rat marrow stromal cell attachment, spreading, and infiltration. Cell attachment after 24 h did not increase with increasing number of nanofibers, but the presence of nanofibers enhanced cell spreading as evidenced by stronger F-actin staining. Additionally, increasing the thickness of the nanofiber layer reduced the infiltration of cells into the scaffolds under both static and flow perfusion culture for the specific conditions tested. The scaffold design presented in this study allows for cellular infiltration into the scaffolds while at the same time providing nanofibers as a physical mimicry of extracellular matrix.
电纺支架的物理和空间结构几何形状对其在组织工程策略中的应用十分重要。在本研究中，分别电纺制备了平均纤维直径在2至10微米范围内的聚己内酯微纤维支架，以确定可重复制备支架所需的参数。随着纤维直径的增加，通过压汞法测量的支架平均孔径增大（值在20至45微米之间），同时观察到孔隙率恒定。为了利用微纤维层的较大孔径和纳米纤维层的纳米尺寸，通过连续电纺制备了层状支架。这些支架由聚己内酯微纤维和聚己内酯纳米纤维的交替层组成。通过在不同时间电纺纳米纤维层，可以调节纳米纤维层的厚度。生成了顶部带有不同厚度纳米纤维的微纤维支架组成的双层结构，并评估了它们影响大鼠骨髓基质细胞附着、铺展和浸润的潜力。24小时后的细胞附着并未随着纳米纤维数量的增加而增加，但纳米纤维的存在增强了细胞铺展，这通过更强的F - 肌动蛋白染色得以证明。此外，在特定测试条件下，增加纳米纤维层的厚度会减少静态和流动灌注培养条件下细胞向支架内的浸润。本研究中提出的支架设计允许细胞浸润到支架中，同时提供纳米纤维作为细胞外基质的物理模拟物。
