Nanoelectronics for probing the brain with (sub)cellular resolution

Carmen Bartic

Unraveling the mechanisms governing the integrated activity of the brain is without question one of the greatest scientific challenge of today with major societal and economic consequences. In this context, nanoelectronic engineering can provide novel approaches to decipher the connectivity and function of the neuronal circuits with unpreceded resolution. Electrogenic cells like neurons can directly exchange information with electronic devices thanks to the iono-electronic conversion. Nanotechnologies allow constructing neuro-electronic hybrid systems based on the concept of an artificial synapse between a cell (pre-synaptic element) and a micro/nano device (post-synaptic element). Interfacing cells with hardware is a complex problem requiring integration of biologically active molecules with biocompatible, active nano/microprobes able to pick up and/or trigger both electrical and chemical cellular signals. By combining top-down and bottom up micro- and nanofabrication techniques one can create a cellular microenvironment on nanoelectronic devices and cope with the limited biocompatibility of the most IC materials. Recently, the emerging field of optogenetics offers new opportunities for deciphering the brain functions by high-speed optical probing and controlling genetically targeted neurons interacting within intact neural circuits. In this context optoelectronics provides the level of functionality and miniaturization required for the application of optogenetic approaches in vivo. The purpose of this lecture is to highlight these novel scientific methodologies and at the same time underline the challenges and potential technological solutions for achieving efficient signal coupling between a cell and an electronic device in a complex neuronal network at both electrical and chemical levels.