Neuronal response to nanotopographies: a cross-species perspective

Neurite pathfinding is a fundamental process in nervous system development and regeneration, influenced by molecular and physical cues. While chemical signals have been extensively studied, the impact of nanotopographical features on neurite elongation remains incompletely understood. Here, we systematically investigate the role of nanoscale topographies in guiding neurite growth using culture substrates patterned with silicon dioxide (SiO₂) nanotopographical features. We examined the effects of four distinct nano patterns: Thick Lines, Thin Lines, Circles, and Zigzags at two heights (100 nm and 240 nm) on the pattern of regenerating neurons from invertebrate (medicinal leech) and mammalian (mouse) cortical neurons. Furthermore, we developed an approach to the assess the effects of the nanoscale topographies on growth rate, a parameter which could affect the timing of regeneration, and, thus, may be critical for successful reinnervation. The present data indicate that growth cone interactions with the nanotopographical cues primarily influence guidance behavior rather than elongation rate. Moreover, our results reveal that increasing the nanotopographical height to 240 nm significantly enhanced neurite guidance, with the Thick Lines pattern showing the strongest effect on sustained neurite growth along the topographical cues. Remarkably, mouse cortical neurons exhibited a significantly greater capacity to align with nanotopographical cues than leech neurons, for longer distances, suggesting species-specific differences in topography guided neurite navigation. Notably, leech neurons present a well-established regenerative capacity but with less alignment to the nanoscale structures, suggesting that these abilities are not necessarily coupled. Time-lapse analysis further showed that nanotopographical contact altered neurite growth directly without affecting elongation rate. Additionally, we introduce a novel wave-shaped(Slalom) nanotopography, which highlights the ability of mammalian neurons to dynamically adjust growth direction in response to changing nanoscale cues . These findings provide new insights into the role of nanotopography in neuronal regeneration and offer a promising foundation for designing biomaterial scaffolds and neuroengineering strategies aimed at enhancing neural repair.