Neural stem/progenitor cells (NSCs) are capable of self-renewal and differentiation into all cell types found within the central nervous systems: neurons, astrocytes and oligodendrocytes.  The self renewal and differentiation in their native microenvironment is regulated by a complex array of biochemical and topographical cues.  However, the mechanisms of control over these fate specification steps remain elusive.  Our work has focused on using a synthetic nanofiber matrix as a cellular substrate in place of the 2-dimensional plastic plates traditionally used for cell culture.  We have shown that the differentiation fate of rat NSCs was significantly influenced by using a nanofiber matrix.  Furthermore, the average diameter fibers influenced the specific cell type produced when NSCs undergo differentiation.  When prompted to differentiate, 40% more of oligodendrocytes were obtained from NSCs cultured on 283-nm fibers comparing with the tissue culture polystyrene surface.  In contrast, 20% more neuronal precursors were detected on the 749-nm fibers.  Results from this study indicate that fiber topography plays an important role in regulating how neural stem cells determine their fate by cell-matrix interaction.