Determining the mechanical properties of electrospun poly-ε-caprolactone (PCL) nanofibers using AFM and a novel fiber anchoring technique
Determining the mechanical properties of electrospun poly-ε-caprolactone (PCL) nanofibers using AFM and a novel fiber anchoring technique
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DOI：
10.1016/j.msec.2015.09.102
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发表时间：
2016-02-01
影响因子：
7.9
通讯作者：
Guthold, Martin
中科院分区：
文献类型：
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作者：
Baker, Stephen R.;Banerjee, Soham;Guthold, Martin
由于其低成本，生物相容性和缓慢的生物吸收，聚-ε-己内酯（PCL）仍然是一个合适的材料选择生物医学工程应用。我们使用原子力显微镜（AFM）/光学显微镜技术相结合，以确定个别静电纺丝PCL纳米纤维的直径在440-1040 nm之间的关键机械性能。与蛋白质纳米纤维相比，PCL纳米纤维显示出低得多的粘附力，因为当机械操作时它们在基底上滑动。因此，我们首先开发了一种新的技术，将单个PCL纳米纤维锚在基底上的微米级脊上，然后对锚定的纳米纤维进行机械测试。当保持恒定应变时，拉伸应力分别以1.0 +/- 0.3 s和8.8 +/- 3.1 s的快弛豫时间和慢弛豫时间弛豫。总拉伸模量为62 +/-26 MPa，拉伸模量的弹性（非松弛）分量为53 +/-36 MPa。单个PCL纤维可以弹性拉伸（没有永久变形）至19- 23%的应变。PCL纳米纤维是相当可延伸的;它们可以被拉伸到至少98%的应变，和至少12 MPa的拉伸强度，然后它们从AFM针尖上滑落。在环境条件下老化超过一个月的PCL纳米纤维变得更硬且弹性更小。我们的技术提供了精确的生物力学数据，这些数据是指导细胞和其他生物医学设备支架构建所需的。(C)2015作者由爱思唯尔公司出版
Due to its low cost, biocompatibility and slow bioresorption, poly-epsilon-caprolactone (PCL) continues to be a suitable material for select biomedical engineering applications. We used a combined atomic force microscopy (AFM)/optical microscopy technique to determine key mechanical properties of individual electrospun PCL nanofibers with diameters between 440-1040 nm. Compared to protein nanofibers, PCL nanofibers showed much lower adhesion, as they slipped on the substrate when mechanically manipulated. We, therefore, first developed a novel technique to anchor individual PCL nanofibers to micrometer-sized ridges on a substrate, and then mechanically tested anchored nanofibers. When held at constant strain, tensile stress relaxed with fast and slow relaxation times of 1.0 +/- 0.3 s and 8.8 +/- 3.1 s, respectively. The total tensile modulus was 62 +/- 26 MPa, the elastic (non-relaxing) component of the tensile modulus was 53 +/- 36 MPa. Individual PCL fibers could be stretched elastically (without permanent deformation) to strains of 19-23%. PCL nanofibers are rather extensible; they could be stretched to a strain of at least 98%, and a tensile strength of at least 12 MPa, before they slipped off the AFM tip. PCL nanofibers that had aged for over a month at ambient conditions became stiffer and less elastic. Our technique provides accurate nanofiber mechanical data, which are needed to guide construction of scaffolds for cells and other biomedical devices. (C) 2015 The Authors. Published by Elsevier B.V.