Full bandwidth electrophysiology of seizures and epileptiform activity enabled by flexible graphene micro-transistor depth neural probes

Abstract

Mapping the entire frequency bandwidth of neuronal oscillations in the brain is of paramount importance for understanding physiological and pathological states. The ability to record simultaneously infraslow activity (<0.1 Hz) and higher frequencies (0.1-600 Hz) using the same recording electrode would particularly benefit epilepsy research. However, commonly used metal microelectrode technology is not well suited for recording infraslow activity. Here we use flexible graphene depth neural probes (gDNP), consisting of a linear array of graphene microtransistors, to concurrently record infraslow and high frequency neuronal activity in awake rodents. We show that gDNPs can reliably record and map with high spatial resolution seizures, post-ictal spreading depolarisation, and high frequency epileptic activity through cortical laminae to the CA1 layer of the hippocampus in a mouse model of chemically-induced seizures. We demonstrate functionality of chronically implanted devices over 10 weeks by recording with high fidelity spontaneous spike-wave discharges and associated infraslow activity in a rat model of absence epilepsy. Altogether, our work highlights the suitability of this technology for in vivo electrophysiology research, in particular, to examine the contributions of infraslow activity to seizure initiation and termination.

Advancement and Challenges of Biosensing Using Field Effect Transistors

“…Graphene stands tall amongst the nanomaterials owing to its unique properties of outstanding tensile strength of 130 GPa and modulus of 1000 GPa, ultra-large surface area and carrier mobility that leads to ultra-fast charge transport capability, chemical and electrochemical inertness and biocompatibility [ 10 , 11 ]. Thus, it is extensively used in new interesting areas of research such as wearable or implantable sensor technology for development of smart, soft contact lens and in neural probes [ 12 , 13 ]. The innovative sensing approach in graphene also exhibits edge functionalization, that is, biomolecular conjugation at the edge of the graphene sheet for highly sensitive detection of biomolecules [ 14 ].…”