Designer Neural Networks with Embedded Semiconductor Microtube Arrays

Here we present a designer's approach to building cellular neuronal networks based on a biocompatible negative photoresist with embedded coaxial feedthroughs made of semiconductor microtubes. The diameter of the microtubes is tailored and adjusted to the diameter of cerebellum axons having a diameter of 2-3 μm. The microtubes as well as the SU-8 layer serve as a topographical cue to the axons. Apart from the topographical guidance, we also employ chemical guidance cues enhancing neuron growth at designed spots. Therefore, the amino acid poly-l-lysine is printed in droplets of pl volume in the front of the tube entrances. Our artificial neuronal network has an extremely high yield of 85% of the somas settled at the desired locations. We complete this by basic patch-clamp measurements on single cells within the neuronal network.