Organotypic and axonal culture on the injury device. A) MAP-2 staining of organotypic slices on the strain injury device. i) Day 7, ii) Day 14, iii) Day22, (DG – dentate gyrus), and iv) CA1 neuron on Day22, showing apical and basal branching. Scale, 1mm. B) Axon extension within microchannels (50μm × 6μm). Confirmation that extension is indeed axons by immunostaining for Tau (axonal marker). Scale, 50μm. C) PDMS microchannel dimensions control the number of entering axons, i) 50μm wide microchannels = large number of entering axons, and ii) 25μm wide microchannels = single axons/small number of entering axons. Scale, 20μm.