Modulation of a materials surface topography can be used to steer various aspects of adherent cell behaviour, such as cell directional organization. Especially nanometric sized topographies, featuring sizes similar to for instance the axons of the spiral ganglion cells, are interesting for such purpose. Here, we utilized nanosized grooves in the range of 75-500 nm, depth of 30-150 nm, and pitches between 150 nm and 1000 nm for cell culture of neuron-like PC12 cells. The organizational behaviour was evaluated after 7 days of culture by bright field and scanning electron microscopy. Nanotopographies were shown to induce aligned cell-body/axon orientation and an increased axonal outgrowth. Our findings suggest that a threshold for cell body alignment of neuronal cells exists on grooved topographies with a groove width of 130 nm, depth of 70 nm and pitch of 300 nm, while axon alignment can already be induced by grooves with 135 nm width, 52 nm depth and 200 nm pitch. However, no threshold has been found for axonal outgrowth, as all of the used patterns increased outgrowth of PC12-axons. In conclusion, surface nanopatterns have the potential to be utilized as an electrode modification for a stronger separation of cells, and can be used to direct cells towards the electrode contacts of cochlear implants.
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