Sensing Ion Channel In Neuron Networks With Graphene Field Effect Transistors

Graphene, the atomically-thin honeycomb carbon lattice, is a highly conducting 2D material whose exposed electronic structure offers an ideal platform for chemical and biological sensing. Its biocompatible, flexible and chemically inert nature associated with the lack of dangling bonds, offers novel perspectives for direct interfacing with biological molecules. Combined with its exceptional electronic and optical properties, this promotes graphene as a unique platform for bioelectronics. Among the successful bio-integrations of graphene, the detection of action potentials in numerous electrogenic cells including neurons has paved the road for the high spatio-temporal and wide-field mapping of neuronal activity. Ultimate resolution of sensing ion channel activity can be achieved with neural interfaces, and it was shown that macroscale electrodes can record extracellular current of individual ion channels in model systems, by charging the quantum capacitance of large graphene monolayer (mm(2)). Here, we show the field effect detection of ion channel activity within neuron networks, cultured during several weeks above graphene transistor arrays. Dependences upon drugs, reference potential gating and device geometry confirm the field effect detection of individual ion channel and suggest a significant contribution of grain boundaries, which provide highly sensitive nanoscale-sized sensing sites. Our theoretical analysis and simulations demonstrate that the ion gating of a single grain boundary in liquid affects the electronic transmission of the whole transistor channel, resulting in significant conductance variations. Monitoring the ion channels activity is of great interest as most of neurodegenerative diseases relied on channelopathies, which rely on ion channel abnormal activity. Thus, such highly sensitive and biocompatible neuro-electronics which open the way to FET detection at the sub-cell precision should be useful for a wide range of fundamental and applied research areas, including brain-on-chip, pharmacology, and in vivo monitoring or diagnosis.