含有導電高分子的奈米纖維結構及電刺激對細胞神經分化的影響

Abstract

材料的表面型態和外在刺激可以提供物理化學的改變，進而促進神經細胞的增生和分化。PC12細胞在有神經分化因子的刺激下容易分化成神經細胞，因此我們以PC12細胞作為主要研究的細胞。為了施予外在的電刺激給PC12，我們利用PEDOT:PSS作為材料的主要元素之一。PEDOT是一種已被廣泛應用在各種生醫材料的導電高分子，具有類似π電子的共振導電效果的導電高分子亦有：PPy、PT、PANI…等。 在我們的研究中，我們利用電紡絲的技術製造了具有方向性以及非方向的奈米纖維。奈米纖維提供神經細胞生長一個高表面積、具有一定機械強度、極高方向性的生長環境。除此之外，許多文獻亦指出適量的外加電刺激可以促進神經細胞的延伸。因此我們改變正向性奈米纖維的電紡絲時間，分別控制電紡絲的時間為10、20、40分鐘。我們的主要目標即研究材料型態和外加電刺激對不同時間電紡絲時間的基材之影響。 PC12在具有正向性的電紡絲上主要有兩個神經突觸方向且沿著奈米纖維生長；而在非方向性的電紡絲上則有許多突觸產生，從此可以得知材料表面的型態對神經細胞的生長具有很大的影響。另外，當我們增加電紡絲的時間並且外加電刺激，我們發現PC12神經的突觸比起沒有電刺激的組別更加明顯。我們研究結果顯示材料表面型態和外加電刺激對神經細胞生長都具影響。

Surface morphology and external stimuli can generate physicochemical changes that influence proliferation and differentiation of neural cells. Since Pheochromocytoma 12 (PC12) tend to differentiate into neuron-like cells with nerve growth factor (NGF), we used PC12 as a model for neural differentiated research. For electrical stimulation to PC12, we used PEDOT:PSS as a main polymer in our material. Poly(3,4-ethylenedioxythiophene) (PEDOT) is a π-conjugated polymer which is known to be conductive such as polypyrrole (PPy), polythiophene (PT), polyaniline (PANI). Also, PEDOT has already been widely used in biomaterials. We fabricated aligned and random PEDOT:PSS nanofibers by electrospinning process which is recognized as an efficient approach for the production of nanoscale fibrous mats. It provides large surface areas and highly aligned direction suitable for neuron extension. Furthermore, electrical stimulation (ES) of neurons has also been shown to lead neurite outgrowth according to many research. In this research, we electrospun aligned and random nanofibers to observe the morphological impact on PC12 growth. Also, aligned nanofibers which were electrospun for 10, 20, and 40 min respectively were used to investigate the influence of conductive mesh on PC12 cells under electrical stimulation. Our results demonstrated that PC12 cells on aligned topography predominantly displayed bipolar neurites along the direction of the nanofibers. On the other hand, PC12 cells on flat surface and random nanofibers produced numerous neurites. We could conclude that morphology plays an important role on the outgrowth of neurites. Also, as we increase the electrospinning time of aligned nanofibers, the neurites outgrowth of PC12 are more obvious compared to the PC12 which are not exposed to electrical. Therefore, our data suggests that both nano-fibrous morphology and electrical stimulation support neurite outgrowth and neuronal differentiation.