Effects of mechanical stimuli and microfiber-based substrate on neurite outgrowth and guidance

We introduced mechanical stimuli and micropatterned substrate with microfibers to investigate their effects on neurite outgrowth along with nerve growth factor in vitro. Two types of surface morphology were used: a surface that was coated by laminin alone and a surface where in microfibers was added on the laminin surface. PC-12 cells were seeded on both surface types and cultured for 2 d. The magnitudes of shear stresses ranged from 0.10 to 1.50 Pa. Two days after stimulation by shear stress, neurite outgrowth and its direction were measured by F-actin staining and digital image processing. When a shear stress of 0.50 Pa was applied, neurons were most highly aligned with microfibers. The average length of neurite outgrowth with microfibers was largest at a shear stress of 0.25 Pa. The results suggest that micropatterned fibers and fluid-induced shear stress are promising for stimulating neurite outgrowth in a desired direction.