Neuronal Migration on Silicon Microcone Arrays with Different Pitches

Neuronal migration is a complicated but fundamental process for proper construction and functioning of neural circuits in the brain. Many in vivo studies have suggested the involvement of environmental physical features of a neuron in its migration, but little effort has been made for the in vitro demonstration of topography-driven neuronal migration. This work investigates migratory behaviors of primary hippocampal neurons on a silicon microcone (SiMC) array that presents 14 different pitch domains (pitch: 2.5-7.3 µm). Neuronal migration becomes the maximum at the pitch of around 3 µm, with an upper migration threshold of about 4 µm. Immunocytochemical studies indicate that the speed and direction of migration, as well as its probability of occurrence, are correlated with the morphology of the neuron, which is dictated by the pitch and shape of underlying SiMC structures. In addition to the effects on neuronal migration, the real-time imaging of migrating neurons on the topographical substrate reveals new in vitro modes of neuronal migration, which have not been observed on the conventional flat culture plate, but been suggested by in vivo studies.