Three dimensional microelectrodes enable high signal and spatial resolution for neural seizure recordings in brain slices and freely behaving animals

Abstract

Neural recordings made to date through various approaches—both in-vitro or in-vivo—lack high spatial resolution and a high signal-to-noise ratio (SNR) required for detailed understanding of brain function, synaptic plasticity, and dysfunction. These shortcomings in turn deter the ability to further design diagnostic, therapeutic strategies and the fabrication of neuro-modulatory devices with various feedback loop systems. We report here on the simulation and fabrication of fully configurable neural micro-electrodes that can be used for both in vitro and in vivo applications, with three-dimensional semi-insulated structures patterned onto custom, fine-pitch, high density arrays. These microelectrodes were interfaced with isolated brain slices as well as implanted in brains of freely behaving rats to demonstrate their ability to maintain a high SNR. Moreover, the electrodes enabled the detection of epileptiform events and high frequency oscillations in an epilepsy model thus offering a diagnostic potential for neurological disorders such as epilepsy. These microelectrodes provide unique opportunities to study brain activity under normal and various pathological conditions, both in-vivo and in in-vitro, thus furthering the ability to develop drug screening and neuromodulation systems that could accurately record and map the activity of large neural networks over an extended time period.

Inkjet-printed 3D micro-ring-electrode arrays for amperometric nanoparticle detection

“…This is of particular interest in applications if the electrodes are required to penetrate into soft matter samples such as organoids or tissue slices. 34,35…”

“…This is of particular interest in applications if the electrodes are required to penetrate into soft matter samples such as organoids or tissue slices. 34,35 To characterize the fabrication process of the 3D electrodes we printed arrays with electrodes of different height by changing the applied droplet number using a single nozzle (see Fig. 3a).…”

Nanomaterial-based microelectrode arrays for in vitro bidirectional brain–computer interfaces: a review

“…In microstructure, standard planar electrodes have evolved into raised 3D electrodes, which can promote the engulfment into the cell, achieving concurrent extracellular and intracellular recording. Methods abound, one of which is to bond gold microwires with diameters of 17 μm or 25 µm onto the surface of the planar electrodes 49 . In addition, a facile height-controllable fabrication method for gold pillar-shaped electroplated microstructures was developed 50 .…”

Toward the Next Generation of Neural Iontronic Interfaces

“…[43,44] Copyright 2018, 2020, Elsevier, Springer Nature) to slices and organoids (reproduced with permission. [35,45,46] Copyright 2021, 2021, 2021, Forschungszentrum Jülich, Elsevier, AAAS) to even full brains. Reproduced with permission.…”

“…The combination of the global geometry, the choice of electrodes, and the bulk material enable the study of a host of systems ranging from a few neurons in vitro (reproduced with permission [43,44]. Copyright 2018, 2020, Elsevier, Springer Nature) to slices and organoids (reproduced with permission [35,45,46]. Copyright 2021, 2021, 2021, Forschungszentrum Jülich, Elsevier, AAAS) to even full brains.…”