Figure 1.

The axonal sample isolation device allows for axons to be physically isolated from other neuronal components. (a) A schematic of the microfluidic chip for neuronal growth and axonal isolation. Three large channels, 1.5 mm wide and ∼300 μm high, are spaced 500 μm apart. The inside channel is designated the somal channel (shown in red) is where freshly dissociated neurons are plated. The outside channels are designated the axonal channels (shown in green) and are only filled with media. The three channels are all connected by small microchannels that are 10 μm wide, 3 μm high, 500 μm lonh, and spaced 20 μm apart (shown in black in the inset, not to scale). These microchannels are too small to allow for cell bodies to enter, so only dendrites and axons grow into them. Dendrites do not grow to the same length or as quickly as axons grow, so at 14 d.i.v. they are still significantly shorter than the 500 μm microchannels connecting the somal chambers to the axonal chamber (see MAP2-labeled dendrites in b, top panel). Axons, however, grow long enough and quickly enough to fill the axonal chambers with a dense mat of processes (see tau-labeled axons in b, middle panel). Two-color overlay between the MAP2-labeled (green) dendrites tau-labeled (red) axons at 14 d.i.v. is shown in b, bottom panel. Scale bar is 100 μm.