A high-performance transparent graphene/vertically aligned carbon nanotube (VACNT) hybrid electrode for neural interfacing

Neural interfaces that do not damage cells or tissues are key to connecting brain functions to neural prosthetics. Here, we designed a transparent graphene/vertically aligned carbon nanotube (VACNT) electrode capable of extracellularly recording spontaneous action potentials in Sprague-Dawley rat primary cortex neurons. Graphene provided the dual function of contacting the VACNTs and visually monitoring the cell viability. The hybrid electrodes exhibited remarkably high peak-to-peak signal amplitudes (1600 μV) and low noise levels, presumably due to tight junction formation between the cells and the deformed CNTs. Spike simulation and high-resolution transmission electron microscopy (HRTEM) imaging confirmed the excellent interfacial characteristics of the cells and the transparent hybrid electrodes. Transparent graphene-vertically aligned carbon nanotube (VACNT) electrodes enable the dual function of optical cell monitoring and cell electrical signal measurements with exceptionally high signal amplitude.