their advantages in functional integration, biomedical engineering materials have been used to facilitate nerve regeneration and to regulate neural behaviors through the use of nerve guidance conduits, [3][4][5] bioactive molecule patterning, [6][7][8][9][10] conductive elements, [11][12][13] and so on. Among these, topographical conductive surfaces have the potential to induce neuron orientation, and functional materials possessing such surfaces have aroused extensive attention. [14,15] As one such material, superaligned carbon-nanotube sheets (SA-CNTs) have excellent electrical conductivity and mechanical properties and thus have been employed in neurobiological studies such as electrophysiological maturation, [16] growth behavior regulation, and nerve regeneration. [17] However, despite the progress made in the application of SA-CNTs, these materials only influence the cultured cells by their aligned direction, and this may limit their efficiency in inducing oriented cell growth due to the difference between the nanometer scale of SA-CNTs and the micrometer scale of cells. In addition, because of the lack of 3D topological structures, these SA-CNTs make it difficult to simulate the extracellular matrix in neural tissues. Therefore, topographical conductive materials with 3D structures and cellular orientation capabilities are still sought.
Spiral ganglion neuron (SGN) degeneration canlead to severe hearing loss, and the directional regeneration of SGNs has shown great potential for improving the efficacy of auditory therapy. Here, a novel 3D conductive microstructure with surface topologies is presented by integrating superaligned carbon-nanotube sheets (SA-CNTs) onto Morpho Menelaus butterfly wings for SGN culture. The parallel groove-like topological structures of M. Menelaus wings induce the cultured cells to grow along the direction of its ridges. The excellent conductivity of SA-CNTs significantly improves the efficiency of cellular information conduction. When integrating the SA-CNTs with M. Menelaus wings, the SA-CNTs are aligned in parallel with the M. Menelaus ridges, which further strengthens the consistency of the surface topography in the composite substrate. The SA-CNTs integrated onto butterfly wings provide powerful physical signals and regulate the behavior of SGNs, including cell survival, adhesion, neurite outgrowth, and synapse formation. These features indicate the possibility of directed regeneration after auditory nerve injury.