Figure 1.
The microfluidic-based culture platform directs axonal growth of CNS neurons and fluidically isolates axons. (a) The culture chamber consists of a PDMS mold containing a relief pattern of somal and axonal compartments (1.5 mm wide, 7 mm long, 100 mm high) connected by microgrooves (10 μm wide, 3 μm high). The optically transparent PDMS adheres to a polylysine-coated coverslip. Rat CNS neurons (green) are added to the somal-side reservoir and are drawn into the somal channel (black) by capillary action. Within 3–4 d, axonal growth is guided into the axonal side (yellow) through the microgrooves. (b) A volume difference between the somal side and axonal side (∼50 μl) allows chemical microenvironments to be isolated to axons for over 20 h owing to the high fluidic resistance of the microgrooves. Similarly, the volume difference can be reversed to isolate a chemical microenvironment to the somal side. (c) Fluidic isolation of Texas red dextran (top panel) to the axonal compartment demonstrates that axonal or somatic microenvironments can be independently manipulated using this culture platform. Axonally restricted application of CellTracker Green (middle panel) backtracked neurons from their isolated axons. The bottom image is the merged figure. Scale bar, 100 μm. (d) Counts of radioactivity in samples from somal and axonal compartments after [35S]methionine was localized to the axonal compartment for over 20 h. Counts in the somal compartment (3.7 c.p.m. ± 1.5 s.e.m.) were similar to background levels. Error bars, s.e.m. (n = 3).