The effect of an electrically conductive carbon nanotube/collagen composite on neurite outgrowth of PC12 cells

We report the preparation of an electrically conductive composite composed of collagen and carbon nanotubes (CNTs) and its use as a substrate for the in vitro growth of PC12 cells. Morphological observation by scanning electron microscopy (SEM) indicated the homogenous dispersion of CNTs in the collagen matrix. Four-point probe and cyclic voltammogram studies demonstrated the enhanced electroactivity and a lowered electrical resistivity of the resulting composites even at low loadings (<5%) of CNTs. Cellular metabolic activity was evaluated by the MTT assay. Cell viability was systematically related to the amount of CNTs embedded in the collagen matrix. SEM and immunofluorescent images have indicated that the morphological features of PC12 cells were dominantly influenced by electrical potential. Greater neurite extension was preferentially induced on the exposure of electrical stimulation by facilitating the differentiation of PC12 cells into neurons indicated by more significant filopodium extension. These electrically conductive, biocompatible CNT/collagen composites could be of benefit for the development of novel neural electrodes, enhancing the growth, differentiation, and branching of neurons in an electrically driven way. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 95A: 510-517, 2010.