Collaborative Research: BRAIN EAGER: Stretchable graphene transistors for high signal, high channel count neural recording

Cornell University, Ithaca NY

Investigators

Abstract

This award is jointly made by two programs the Instrument Development for Biological Research program (IDBR) and Emerging Frontiers (EF) in the Directorate of Biological Sciences (BIO). A key roadblock to expanding our knowledge of the brain is that existing tools to probe its function are simply not up to the enormity of the task. Techniques for recording neural signals allow at most signals from tens or hundreds of neurons to be recorded, when thousands or even millions are needed. To address this challenge, improved types of sensors are required that record neural activity with greater signal quality and are more suited to parallel recording than current approaches. This collaborative project will develop a new type of sensor based on flexible graphene transistors. Graphene is an atomically thin sheet of carbon atoms that exhibits desirable physical, chemical, and electrical properties for interfacing with biological systems. However, the use of graphene transistors for single neuron sensing is largely unexplored. Open questions include the nature of the contact between the neuron and the graphene, the ultimate strength of electrical signals, and the long-term biocompatibility of graphene-based electrodes in the brain. Our proposed work will address these fundamental questions. If successful, this project will ultimately lead to societal benefits such as better neural prosthetics and new treatments for neurological disorders. Training opportunities at the interface of nano- and neuroscience, a key area of need for America?s technological future, will be available for graduate students. Graphene can be nanofabricated into arrays of conformable, stretchable transistors using techniques borrowed from the Japanese paper art of kirigami. Prior work of this research team has shown that unlike traditional electronic devices, such graphene transistors are both extremely flexible and can stretch by > 100% without degrading their electrical properties. The current project will investigate the electrical and mechanical interactions between kirigami graphene and individual neurons. Graphene will be cut into different patterns to optimize the mechanical contact between graphene and single neurons. Wrapping of graphene on the neuron will be maximized and the graphene will be used to measure voltage spikes produced by individual neurons, both in vitro and in vivo. With optimized conformal contact between graphene and neurons it will be possible to measure a large fraction of the intracellular potential (~ 70 mV). The semiconducting properties of graphene will also be used to amplify the bioelectronic signals to robust levels to facilitate multiplexed detection of thousands of neuron signals.