BioengineeringDepartment, University of California, Berkeley, CA 94720 USA.
IEEE Trans Nanobioscience. 2012 Mar;11(1):15-21. doi: 10.1109/TNB.2011.2159621. Epub 2011 Jun 27.
Engineered scaffolds simultaneously exhibiting multiple cues are highly desirable for neural tissue regeneration. To this end, we developed a neural tissue engineering scaffold that displays submicrometer-scale features, electrical conductivity, and neurotrophic activity. Specifically, electrospun poly(lactic acid-co-glycolic acid) (PLGA) nanofibers were layered with a nanometer thick coating of electrically conducting polypyrrole (PPy) presenting carboxylic groups. Then, nerve growth factor (NGF) was chemically immobilized onto the surface of the fibers. These NGF-immobilized PPy-coated PLGA (NGF-PPyPLGA) fibers supported PC12 neurite formation ( 28.0±3.0% of the cells) and neurite outgrowth (14.2 μm median length), which were comparable to that observed with NGF (50 ng/mL) in culture medium ( 29.0±1.3%, 14.4 μm). Electrical stimulation of PC12 cells on NGF-immobilized PPyPLGA fiber scaffolds was found to further improve neurite development and neurite length by 18% and 17%, respectively, compared to unstimulated cells on the NGF-immobilized fibers. Hence, submicrometer-scale fibrous scaffolds that incorporate neurotrophic and electroconducting activities may serve as promising neural tissue engineering scaffolds such as nerve guidance conduits.
为了实现神经组织再生，同时展现多种信号的工程化支架是非常理想的。为此，我们开发了一种具有亚微米级特征、导电性和神经营养活性的神经组织工程支架。具体而言，我们将聚乳酸-共-羟基乙酸（PLGA）纳米纤维进行静电纺丝，并在其表面涂覆一层纳米厚的带有羧基的导电聚苯胺（PPy）。然后，我们将神经生长因子（NGF）化学固定在纤维表面。这些 NGF 固定的 PPy 涂层的 PLGA（NGF-PPyPLGA）纤维支持 PC12 神经突形成（细胞的 28.0±3.0%）和神经突生长（中值长度 14.2 μm），与培养基中 NGF（50 ng/mL）观察到的结果相当（29.0±1.3%，14.4 μm）。与未刺激的 NGF 固定纤维上的细胞相比，PC12 细胞在 NGF 固定的 PPyPLGA 纤维支架上进行电刺激，分别使神经突发育和神经突长度进一步提高了 18%和 17%。因此，具有神经营养和导电活性的亚微米级纤维支架可能成为有前途的神经组织工程支架，例如神经引导导管。
