This study demonstrates neural stem cells forming neurosphere-like three-dimensional adherent spheroids on chitosan membranes. Their state can be maintained for at least fifteen days, during which period the spheroids increase their size and number. After this period, the neural stem cells start to migrate out of the spheroids, which change in size when the culture period is prolonged. It is believed that the spheroid formation on chitosan can maintain the self-renewal and plasticity of neural stern cells for weeks, with differentiation possibly occurring at a later period. The culture of neural stem cells on certain chitosan membranes can be used to purify neural stern cells from a heterogeneous cell population.