Figure 2.

Matrix adhesive ligand density modulates neurite outgrowth and pathfinding in nerve growth factor (NGF) gradients.

(A) Dorsal root ganglion (DRG) spheroid grown in an ELP hydrogel with applied NGF gradient. Blue: DAPI (nuclei). Red: β-Tubulin III (neurites). Green: S100 (Schwann cells). (B) The number of neurites initiated per spheroid was greater in the 3.2 mM RGD matrices. Initiation was biased toward the NGF source in both matrices.*P < 0.05. Error bars represent SEM. (C) Neurite outgrowth ratio was significantly enhanced in the 1.6 mM matrices compared to the 3.2 mM matrices. ****P < 0.0001. Error bars represent SEM. (Figures were reproduced with permission from Romano et al., Small, 2015.)