Bridging Spinal networks: Novel 3D substrates as neural implantable interfaces

In modern neuroscience, significant progress in developing structural scaffolds integrated with the brain is provided by the increasing use of nanomaterials. We show that a multiwalled carbon nanotube self-standing framework, consisting of a three-dimensional (3D) mesh of interconnected, conductive, pure carbon nanotubes, can guide the formation of neural webs in vitro where the spontaneous regrowth of neurite bundles is molded into a dense random net. This morphology of the fiber regrowth shaped by the 3D structure supports the successful reconnection of segregated spinal cord segments.We further observed in vivo the adaptability of these 3D devices in a healthy physiological environment. Our study shows that 3D artificial scaffolds may drive local rewiring in vitro and hold great potential for the development of future in vivo interfaces.

Neural implants in past decades have offered themselves as a promising tool in finding answers for spinal cord injury and yet no practical treatment is available. Glial barrier and functional deficits are major challenges needed to overcome. Here, we have used a unique scaffold fabricated from 3D multiwalled carbon nanotube fibers (CNF) as a neural implant. We investigated long term in vivo effects of this material implanted in L1 hemisection lesione. Functional locomotor recovery measured by BBB rating scale and ladder rung test demonstrated improvement starting from 24 h post-injury over a course of 8 weeks. Footprint analysis revealed early onset of plantar placement in CNF-implanted animals. Tissue reaction to the implant quantified as GFAP and Iba 1-positive area was limited and invasion of neural processes within the implanted scaffold suggests use of carbon nanofibers as a safe and neuron-friendly scaffold.