CMU Array: A 3D Nano-Printed, Customizable Ultra-High-Density Microelectrode Array Platform

Abstract

Microelectrode arrays (MEAs) provide the means to record electrophysiological activity fundamental to both basic and clinical neuroscience (e.g. brain-computer interfaces). Despite recent advances, current MEAs have significant limitations -including recording density, fragility, expense, and the inability to optimize the probe to individualized study or patient needs.Here we address the technological limitations through the utilization of the newest developments in 3D nanoparticle printing. 1 Our 'CMU Arrays' possess previously impossible electrode densities (> 6000 channels/cm 2 ) with tip diameters as small as 10µm. Most importantly, the probes are entirely customizable owing to the adaptive manufacturing process. Any combination of individual shank lengths, impedances, and layouts are possible. This is achieved in part via our new multi-layer, multi material, custom 3D-printed circuit boards, a fabrication advancement in itself. This device design enables new experimental avenues of targeted, large-scale recording of electrical signals from a variety of biological tissues.

Neuropixels 2.0: A miniaturized high-density probe for stable, long-term brain recordings

“…Finally, while single-shank silicon probes like Neuropixels achieve dense coverage along a line, some brain structures are more effectively recorded with other geometries. Several techniques including the Utah array, tetrode arrays, and microwire arrays offer the ability to sample across a plane approximately parallel to the brain surface (Recce and O'Keefe, 1989;Maynard et al, 1997;Saleh et al, 2019;Obaid et al, 2020;Sahasrabuddhe et al, 2020). However, to record in layered or deep structures such as isocortex, striatum, hippocampus, or superior colliculus, it can be ideal to densely sample a plane perpendicular to the brain surface (Shobe et al, 2015;Rios et al, 2016;Scholvin et al, 2016).…”

Non-linear Dimensionality Reduction on Extracellular Waveforms Reveals Cell Type Diversity in Premotor Cortex

“…High-density recording would allow us to perform WaveMAP in an additional dimension (across multiple electrodes) to increase confidence in identified cell classes and localization of signal to somata 44 . Sensitive electrodes providing spatial access to neural activity 96 can also improve our understanding of how these cell classes are organized both parallel and perpendicular to cortical surface 118,119 . This would allow for the identification of “me-types” through electromorphology 37,45 .…”

Sharpened and mechanically durable carbon fiber electrode arrays for neural interfacing

“…Additionally, this array’s archiecture may enable interfacing with difficult to access locations or small autonomic structures that require durable chronic interfaces [7]. The ability to insert individuated, sharpened fibers as an array without assistance may enable larger channel count arrays of small stiff electrodes [57], [58]. The ability to penetrate DRG suggests that these probes may be useful for other vertebrate ganglia, such as the nodose ganglia [59], and invertebrate ganglia, such as those in Aplysia [60].…”

“…Carbon fibers have traditionally been used primarily in the brain, for both electrophysiology and chemical sensing . The ability to insert individuated, sharpened fibers as an array without assistance may enable larger channel count arrays of small stiff electrodes (Obaid et al, 2020;Saleh et al, 2019). Sharpened carbon fibers arrays may be useful for shuttling softer cellular scale electrodes deeper into brain tissue (Luan et al, 2017;X.…”