Fig. 7.

Neurite outgrowth and guidance by surface-associated NGF. DRG explants (a–c) or dissociated DRG neurons (d–f) were cocultured on patterned NGF expression directly after HEK293T fixation (to halt production of NGF) at 24 hr (a,d) and 48 hr (b,e) after HEK293T seeding (neurons and neurites were stained red with TRITC-labeled secondary antibody). Quantification of neurite length, represented as the ratio of the average neurite length toward vs. away from the pattern of expression (c), and neurite orientation (f), while varying the incubation time between cell seedings (9, 24, and 48 hr) and the distance from the pattern center (0.5–2.0 mm). Values are reported as mean ± SEM. Scale bars = 100 μm. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]