Multimodal MEAs for Parallel Electrical Recording and Sub-second Neuromodulator Sensing

Abstract It has been highly challenging to scale up non-genetic, sub-second neuromodulator sensing or integrate it with electrical recording. Recently, we discovered that mild annealing dramatically improved the electrochemical stability of electroplated carbon coating and transformed conventional microelectrodes into sensors similar to carbon fiber electrodes with excellent neuromodulator-sensing performance based on fast-scan cyclic voltammetry (FSCV). Compared to previous carbonization strategies such as pyrolysis of polymer and laser- induced graphitization, low-temperature, FSCV-stable carbon coating is directly applicable to microelectrode arrays (MEAs), enabling unprecedented spatial scaling of FSCV and unparalleled integration with electrophysiological (ephys) recording, while leveraging decades of MEA research and applications. As a demonstration, we have created a monolithic MEA probe with integrated ephys and FSCV capabilities and validated it in vivo in multiple rodent models. Early studies using this probe in awake rats further revealed an unprecedented correlation between striatal gamma oscillation and dopamine release. In three parallel aims, we intend to optimize, benchmark, and thoroughly validate the platform ephys-FSCV MEA probe for high-density neuromodulator sensing and parallel electrical recording in behaving animals. Our multidisciplinary team consists of a materials scientist and neural engineer (Fang) and a systems neuroscientist (van der Meer), who have jointly produced strong preliminary results with successful in vivo validation and neuroscience studies. In addition to establishing the significant and novel multimodal MEA paradigm, which we envision will enable numerous studies in basic and translational neuroscience, we anticipate that the concept of FSCV-stable carbon-coating and the bioengineering of its up-scaling and ephys-integration are generalizable to many other probes, such as DBS and sEEG electrodes and extensible to further technology evolutions and commercial manufacturing.