一种用于再生医学应用的精确组装松散纳米纤维结构的新方法。
A novel method to precisely assemble loose nanofiber structures for regenerative medicine applications.
机构信息
Department of Bioengineering, Clemson University, Charleston, SC 29425, USA.
出版信息
Adv Healthc Mater. 2013 Feb;2(2):343-51. doi: 10.1002/adhm.201200125. Epub 2012 Oct 15.
Polymer nanofibers are favorable for tissue engineering scaffolds because of their high surface-to-volume ratio and biomimicry of the extracellular matrix. Random and uniaxially oriented polymer nanofibers are easily fabricated by conventional electrospinning techniques; however, control over fiber organization within nanofiber structures is limited when they are collected directly from an electrospinning jet. The regenerative medicine applications of electrospun scaffolds could be expanded by developing assembly methods that allow better control of fiber organization. Here, a novel technique is presented that utilizes parallel automated tracks to orient and collect nanofibers from an electrospinning jet. The stabilized fibers are then subsequently assembled into desirable structures. It is difficult to assemble complex structures directly from an electrospinning jet because of high electrical charge and velocities, so this technology adds an intermediate step where nanofibers are immobilized on automated tracks. The result is a continuous steady-state delivery of static stabilized nanofibers that provides a unique and promising platform for automated post processing into useful nanofiber structures. This technique also allows for an indefinite amount of time, as determined by design parameters, for fibers to dry or cool before they contact other nanofibers in the collection site, thus eliminating potential for fiber-to-fiber adhesions even with slow evaporating solvents or high-temperature melts. To demonstrate potential in regenerative medicine applications, several nanofiber structures were fabricated, including: 2D structures with well-controlled fiber density; 3D loosely assembled aligned nanofiber structures with good cell penetration properties; and, complex layer-by-layer 3D aligned fiber structures assembled by integration with post-processing techniques.
聚合物纳米纤维因其高的比表面积与对细胞外基质的仿生特性,而有利于组织工程支架。通过常规的静电纺丝技术可以容易地制备随机和单轴取向的聚合物纳米纤维;然而,当直接从静电纺丝射流收集纳米纤维结构时,对纤维组织的控制是有限的。通过开发允许更好地控制纤维组织的组装方法,可以扩展静电纺丝支架的再生医学应用。在这里,提出了一种新颖的技术,该技术利用平行的自动化轨道来定向和收集静电纺丝射流中的纳米纤维。然后将稳定的纤维随后组装成所需的结构。由于高电荷和速度,难以直接从静电纺丝射流组装复杂结构,因此该技术增加了一个中间步骤,其中纳米纤维被固定在自动化轨道上。结果是连续稳定的静态稳定纳米纤维的稳定输送,为自动化后处理成有用的纳米纤维结构提供了独特而有前途的平台。该技术还允许根据设计参数,在纤维接触收集点中的其他纤维之前,纤维有无限的时间干燥或冷却,从而消除了即使使用蒸发缓慢的溶剂或高温熔体也存在纤维间粘连的可能性。为了证明在再生医学应用中的潜力,制备了几种纳米纤维结构,包括:具有良好纤维密度的可控纤维密度的 2D 结构;具有良好细胞穿透性能的 3D 松散组装的取向纳米纤维结构;以及通过与后处理技术集成组装的复杂的逐层 3D 取向纤维结构。