Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York 12180-3590, United States.
ACS Appl Mater Interfaces. 2013 Oct 23;5(20):10173-84. doi: 10.1021/am402827g. Epub 2013 Oct 11.
In this study, we created a new method of electrospinning capable of controlling the surface structure of individual fibers (fiber nanotopography). The nanotopographical features were created by a phase separation in the fibers as they formed. To control the phase separation, a nonsolvent (a chemical insoluble with the polymer) was added to an electrospinning solution containing poly-l-lactic acid (PLLA) and chloroform. The nanotopography of electrospun fibers in the PLLA/chloroform solution was smooth. However, adding a small weight (<2% of total solution) of a single nonsolvent (water, ethanol, or dimethyl sulfoxide) generated nanoscale depressions on the surface of the fibers unique to the nonsolvent added. Additionally, nanoscale depressions on electrospun fibers were observed to change with dimethyl sulfoxide (DMSO) concentration in the PLLA/chloroform solution. A nonlinear relationship was found between the concentration of DMSO and the number and size of nanotopographical features. The surface depressions did not alter the hydrophobicity of the scaffold or degradation of the scaffold over a two-day period. To determine if fiber nanotopography altered cell behavior, macrophages (RAW 264.7 cells) were cultured on fibers with a smooth nanotopography or fibers with nanoscale depressions. RAW 264.7 cells spread less on fibers with nanoscale depressions than fibers with a smooth topography (p<0.05), but there were no differences between groups with regard to cell metabolism or the number of adherent cells. The results of this study demonstrate the necessity to consider the nanotopography of individual fibers as these features may affect cellular behavior. More importantly, we demonstrate a versatile method of controlling electrospun fiber nanotopography.
在这项研究中，我们创建了一种新的静电纺丝方法，能够控制单个纤维的表面结构（纤维纳米形貌）。纳米形貌特征是通过纤维形成时的相分离产生的。为了控制相分离，将非溶剂（与聚合物不混溶的化学物质）添加到包含聚 L-乳酸（PLLA）和氯仿的静电纺丝溶液中。PLLA/氯仿溶液中静电纺丝纤维的纳米形貌是光滑的。然而，添加少量(<2%总溶液)的单一非溶剂（水、乙醇或二甲基亚砜）会在纤维表面上产生独特的纳米级凹陷，这是非溶剂添加的结果。此外，在 PLLA/氯仿溶液中，观察到纳米级凹陷随着二甲基亚砜（DMSO）浓度的变化而变化。发现 DMSO 浓度与纳米形貌特征的数量和尺寸之间存在非线性关系。表面凹陷不会改变支架的疏水性或支架在两天内的降解。为了确定纤维纳米形貌是否改变细胞行为，将巨噬细胞（RAW 264.7 细胞）培养在具有光滑纳米形貌的纤维或具有纳米级凹陷的纤维上。与具有光滑形貌的纤维相比，RAW 264.7 细胞在具有纳米级凹陷的纤维上的铺展较少（p<0.05），但两组之间在细胞代谢或附着细胞数量方面没有差异。这项研究的结果表明，有必要考虑单个纤维的纳米形貌，因为这些特征可能会影响细胞行为。更重要的是，我们展示了一种控制静电纺丝纤维纳米形貌的多功能方法。
