3D Liquid Microelectrode Arrays for Electrophysiological Analysis of Brain Organoids

Brain organoids have emerged as a substitution of the human brain for clarifying the origins of neurodevelopmental diseases, by understanding their electrophysiological developments and mechanisms in three-dimensional (3D), volumetric neural networks. However, existing devices to record neural signals either contact the surface of organoids or involve the section or invasion by hard materials, which limit the chronic analysis of soft brain organoids.<br/>Herein, we present a liquid 3D microelectrode array (MEA) by high-resolution 3D printing of biocompatible metals for chronic electrophysiological analysis of brain organoids. Recording neural signals from the organoid with this printed device is non-destructive and non-invasive owing to the soft mechanical properties of liquidous metallic probes, which makes long-term analysis possible. The height of these liquid 3D probes is controllable to monitor electrophysiological signals from entire 3D spatial points in the organoid. Furthermore, magnetic control of these liquid 3D probes facilitates the change in their tip position, which can enhance the resolution of spatial points where these bioelectrodes are located inside the organoid. Mapping the recorded signals from different spatiotemporal points of the organoid during cultivation on our device is expected to reveal the electrophysiological development in brain organoids.