Highly Customizable Scaffold-Type 3D Microelectrode Array Platform for Design and Analysis of the 3D Neuronal Network In Vitro

Abstract

Microelectrode arrays (MEAs) are useful biointerfaces for analyzing the functional characteristics of neural networks. Recently, with the increasing interest in the 3D neuronal network in vitro, 3D MEAs have been actively developed. However, because conventional 3D MEAs are fabricated based on conventional planar microfabrication process used in the semiconductor industry, there are limitations in geometry freedom for constructing complex 3D structures, and customization for the various structures and sizes of 3D neuronal network models. In this study, a novel 3D MEA fabrication platform addressing these limitations is proposed. The key concept for fabricating microelectrodes in a 3D space is to automatically fill a hollow 3D insulator printed by a 3D printer with an electrically conductive ink using capillary action. This allowed free arrangement of microelectrodes in 3D space, and it is possible to engineer a 3D neuronal network in vitro in the desired form using a scaffold-type 3D MEA. Furthermore, it is experimentally demonstrated that one can induce functional activity patterns in structurally designed 3D neuronal networks. The functional activity can be analyzed precisely in 3D space with high temporal resolution. It is expected that this platform will further advance the understanding of the physiological characteristics of engineered 3D neuronal networks.