부산대학교 도서관

Advancements in neuroscience are made possible by the progressive development of new tools and techniques that offer researchers the capabilities to image and record more and more aspects of the nervous system. Among them, microelectrode arrays allow us to directly measure and study the electrical activity produced by the brain and other organs of the nervous system with great spatial and temporal resolution. Furthermore, electrodes allow us to bidirectional interface with neural tissue, delivering electrical stimulation that can be used to further study the brain or even to restore lost capabilities. The need for stable and biocompatible materials, yet able to acquire high signal-to-noise recordings and deliver enough current to successfully stimulate neural tissue has driven researchers to explore new materials to fabricate electrodes aimed to interface with the nervous system. Within this framework, we have explored the capabilities of different graphene-based materials to bidirectionally interact with nervous tissue. In this thesis, we have developed low noise rigid single layer graphene (SLG) microelectrode arrays (MEA) and have used them to record electrical activity in primary cortical cultures. We have also developed transparent and flexible SLG probes, containing one macro-electrode, and used them to record electroretinograms (ERG), benchmarking them against the current state of the art for animal recordings using a commercially available clinical setup. Furthermore, we have pushed the capabilities of commercially available electrodes by developing transparent and flexible MEA probes made of SLG, that allow us to obtain spatial information of the corneal potential. In this work, we also present the fabrication of novel reduced graphene oxide (rGO) electrodes; this technology has allowed us to develop rGO MEA with high charge injection capabilities and low electrical noise values. We have demonstrated that these MEA are able sustain healthy hippocampal primary cultures and to bidirectionally interface them, performing simultaneous recording and stimulation. Finally, and to exploit the versatility offered by our graphene-based MEA, we have explored three different techniques to guide and control the growth of neurons plated on top of our SLG and rGO devices, aiming to provide new tools to study bottom-up neuroscience. Overall, the results presented in this thesis prove that graphene-based electrode technology, with its stability, biocompatibility and extraordinary electrical performance, is an extremely valuable tool to perform in vitro and in vivo neuroscience studies.