Electrically Contrasting Periodic Polymer Interfaces Guide Neuronal Growth.

The nervous system constitutes a highly ordered, integrated network of cells. Understanding this neuroanatomical architecture in vitro is fundamental to elucidating the cellular computations underlying functional network formation. Neuronal connectivity orchestrated through axonal pathfinding arises from an interplay of biochemical signals and electromechanical properties of the growth substrate. Our study focuses on how neurons' morphology and spatial organization are affected by the periodic, micrometer-scale patterned stripes of two electrically contrasting polymers-poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). This periodic confinement provides a length-scale-driven cue, which unfolds as a self-organized, spatial guidance phenomenon. Primary cortical cultures on these patterned substrates reveal significant differences-with more elaborate neurite outgrowth and morphological complexity on the PVDF-TrFE stripe. The features observed at the stripe boundaries, along with the network dependence on stripe width, suggest that the neurons exhibit a preference to remain confined within the PVDF-TrFE region, with growth cones deflecting away from the PEDOT:PSS regions. These morphological observations demonstrate a proof-of-concept substrate design for future development of a functional bioinstructive template capable of directing axonal growth, with potential implications for early models of connectivity disorders in vivo.