title: Spinal cord explants use carbon nanotube interfaces to enhance neurite outgrowth and to fortify synaptic inputs.
abstract: New developments in nanotechnology are increasingly designed to modulate relevant interactions between nanomaterials and neurons, with the aim of exploiting the physical properties of synthetic materials to tune desired and specific biological processes. Carbon nanotubes have been applied in several areas of nerve tissue engineering to study cell behavior or to instruct the growth and organization of neural networks. Recent reports show that nanotubes can sustain and promote electrical activity in networks of cultured neurons. However, such results are usually limited to carbon nanotube/neuron hybrids formed on a monolayer of dissociated brain cells. In the present work, we used organotypic spinal slices to model multilayer tissue complexity, and we interfaced such spinal segments to carbon nanotube scaffolds for weeks. By immunofluorescence, scanning and transmission electronic microscopy, and atomic force microscopy, we investigated nerve fiber growth when neuronal processes exit the spinal explant and develop in direct contact to the substrate. By single-cell electrophysiology, we investigated the synaptic activity of visually identified ventral interneurons, within the ventral area of the explant, thus synaptically connected, but located remotely, to the substrate/network interface. Here we show that spinal cord explants interfaced for weeks to purified carbon nanotube scaffolds expand more neuronal fibers, characterized by different mechanical properties and displaying higher growth cones activity. On the other hand, exploring spontaneous and evoked synaptic activity unmasks an increase in synaptic efficacy in neurons located at as far as 5 cell layers from the cell-substrate interactions.
authors.affiliation: Life Science Department, Center for Neuroscience B.R.A.I.N., University of Trieste, via Giorgieri 1, I-34127 Trieste, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Fabbro
authors.forename: Ambra
authors.initials: A
authors.lastname: Villari
authors.forename: Jummi
authors.initials: J
authors.lastname: Laishram
authors.forename: Denis
authors.initials: D
authors.lastname: Scaini
authors.forename: Francesca M
authors.initials: FM
authors.lastname: Toma
authors.forename: Antonio
authors.initials: A
authors.lastname: Turco
authors.forename: Maurizio
authors.initials: M
authors.lastname: Prato
authors.forename: Laura
authors.initials: L
authors.lastname: Ballerini
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004548:Elasticity; D051379:Mice; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon; D009415:Nerve Net / Q000166:cytology / Q000187:drug effects; D016501:Neurites / Q000187:drug effects* / Q000378:metabolism*; D009475:Neurons, Afferent / Q000166:cytology / Q000187:drug effects; D013116:Spinal Cord / Q000166:cytology*; D013569:Synapses / Q000187:drug effects* / Q000378:metabolism*; D046509:Tissue Culture Techniques
chemical_list: D037742:Nanotubes, Carbon