Neuronal Cells Confinement by Micropatterned Cluster-Assembled Dots with Mechanotransductive Nanotopography

Abstract

The in vitro fabrication of neural networks able to simulate brain circuits and to maintain their native connectivity is of strategic importance to gain a deep understanding of neural circuit physiology and brain natural computational algorithm(s). This would also enable a wide-range of applications including the development of efficient brain-on-chip devices or brain-computer interfaces. Chemical and mechanotransductive cues cooperate to promote proper development and functioning of neural networks. Since the 80s, controlled growth of mammalian neuronal cells on micrometric patterned chemical cues with the development of synaptic connections and electrical activity has been reported, however the role of mechanotransductive signaling on the growth/organization of neural networks has not been investigated so far. Here we report the fabrication and characterization of patterned substrates for neuronal culture with a controlled structure both at the nano- and microscale suitable for the selective adhesion of neuronal cells. Nanostructured micrometric dots were patterned on passivated cell-repellent glass substrates by supersonic cluster beam deposition of zirconia nanoparticles through stencil masks. Cluster-assembled nanostructured zirconia surfaces are characterized by nanotopographical features that can direct the maturation of neural networks by mechanotransductive signaling. Our approach produces a controlled microscale pattern of adhesive areas with predetermined nanoscale morphology. We have validated these micropatterned substrates using a neuronal cell line (PC12 cells) and cultured hippocampal neurons. While cells have been uniformly plated on the substrates, they adhered only on the nanostructured zirconia regions, remaining effectively confined inside the nanostructured dots on which they were found to grow, move and differentiate.