Departments of Chemical Engineering, Queen's University, Kingston, ON, Canada.
Biomacromolecules. 2010 Dec 13;11(12):3624-9. doi: 10.1021/bm101078c. Epub 2010 Nov 3.
Semicrystalline poly(l-lactide-co-ε-caprolactone) (P(LLA-CL)) was used to produce electrospun fibers with diameters on the subcellular scale. P(LLA-CL) was chosen because it is biocompatible and its chemical and physical properties are easily tunable. The use of a rotating wire mandrel as a collection device in the electrospinning process, along with high collection speeds, was used to align electrospun fibers. Upon removal of the fibers from the mandrel, the fibers shrunk in length, producing a crimp pattern characteristic of collagen fibrils in soft connective tissues. The crimping effect was determined to be a result of the residual stresses resident in the fibers due to the fiber alignment process and the difference between the operating temperature (T(op)) and the glass-transition temperature (T(g)) of the polymer. The electrospun fibers could be induced to crimp by adjusting the operating temperature to be greater than that of the polymer glass-transition temperature. Moreover, the crimped fibers exhibited a toe region in their stress-strain profile that is characteristic of collagen present in tendons and ligaments. The crimp pattern was retained during in vitro degradation over 4 weeks. Primary bovine fibroblasts seeded onto these crimped fibers attached, proliferated, and deposited extracellular matrix (ECM) molecules on the surface of the fiber mats. These self-crimping fibers hold great promise for use in tissue engineering scaffolds for connective tissues that require fibers similar in structure to that of crimped collagen fibrils.
半晶态聚（L-丙交酯-共-ε-己内酯）（P（LLA-CL））被用于生产直径达到亚细胞级别的电纺纤维。选择 P（LLA-CL）是因为它具有生物相容性，并且其化学和物理性质易于调节。在电纺过程中，使用旋转的金属丝芯作为收集装置，并结合高速收集，以实现纤维的取向排列。当纤维从芯棒上取下时，纤维会在长度上收缩，产生一种特征性的卷曲模式，类似于软结缔组织中的胶原原纤维。卷曲效应是由于纤维取向过程中纤维内残留的应力以及聚合物的操作温度（T(op)）与玻璃化转变温度（T(g)）之间的差异造成的。通过将操作温度调整到高于聚合物玻璃化转变温度，可以诱导电纺纤维发生卷曲。此外，卷曲纤维在其应力-应变曲线中表现出一个脚趾区域，这是肌腱和韧带中存在的胶原的特征。在 4 周的体外降解过程中，卷曲图案得以保留。接种到这些卷曲纤维上的原代牛成纤维细胞附着、增殖，并在纤维垫表面沉积细胞外基质（ECM）分子。这些自卷曲纤维在用于需要类似于卷曲胶原原纤维结构的组织工程支架方面具有很大的应用前景。
