ABSTRACTDifferentiated neurons (dorsal root ganglia and cortical neurons) have been shown to develop longer neurite extensions on softer materials than stiffer ones, but previous studies do not address the ability of neural stem cells to undergo differentiation as a result of material elasticity. In this study, we investigate neuronal differentiation of C17.2 neural stem cells due to growth on polyacrylamide gels of variable elastic moduli. Neurite growth, synapse formation, and mode of division (asymmetric vs. symmetric) were all assessed to characterize differentiation. C17.2 neural stem cells were seeded onto polyacrylamide gels coated with Type I collagen. The cells were then serum starved over a 14 day period, fixed, and analyzed for biochemical markers of differentiation. For division studies, time-lapse imaging of cells on various substrates was performed during serum withdrawal using the Nikon Biostation. Division events were analyzed using ImageJ to quantify sizes of resulting daughter. Data shows that C17.2 cell differentiation (as dictated by number and type of division events) is dependent upon substrate stiffness, with softer polyacrylamide surfaces (140 Pa) leading to increased populations of neurons and increased neurite length. Our data also indicates that the ability of neural stem cells to express synaptic proteins and develop synapses is dependent upon material elasticity.
Maintenance and Neuronal Cell Differentiation of Neural Stem Cells C17.2 Correlated to Medium Availability Sets Design Criteria in Microfluidic Systems