Abstract: The invention relates to methods and devices for size-based separation of undifferentiated cells from a population of cells using curvilinear microfluidic channels. The curvilinear microfluidic channels may be a spiral microfluidic channels. The differentiated cells are spinal cord progenitor cells (SCPCs), neural progenitor cells (NPCs) and/or cells differentiated therefrom. The method may comprise flowing an input population of cells through first and second sequentially connected and fluidically communicating curvilinear microfluidic channels, wherein the first channel is coupled to an inlet and the second channel is coupled to one or more outlets, wherein the first curvilinear microfluidic channel has a smaller cross-sectional area than the second curvilinear microfluidic channel.