Human-Derived Cortical Neurospheroids Coupled to Passive, High-Density and 3D MEAs: A Valid Platform for Functional Tests

Abstract

With the advent of human-induced pluripotent stem cells (hiPSCs) and differentiation protocols, methods to create in-vitro human-derived neuronal networks have been proposed. Although monolayer cultures represent a valid model, adding three-dimensionality (3D) would make them more representative of an in-vivo environment. Thus, human-derived 3D structures are becoming increasingly used for in-vitro disease modeling. Achieving control over the final cell composition and investigating the exhibited electrophysiological activity is still a challenge. Thence, methodologies to create 3D structures with controlled cellular density and composition and platforms capable of measuring and characterizing the functional aspects of these samples are needed. Here, we propose a method to rapidly generate neurospheroids of human origin with control over cell composition that can be used for functional investigations. We show a characterization of the electrophysiological activity exhibited by the neurospheroids by using micro-electrode arrays (MEAs) with different types (i.e., passive, C-MOS, and 3D) and number of electrodes. Neurospheroids grown in free culture and transferred on MEAs exhibited functional activity that can be chemically and electrically modulated. Our results indicate that this model holds great potential for an in-depth study of signal transmission to drug screening and disease modeling and offers a platform for in-vitro functional testing.

Versatile micro-electrode array to monitor human iPSC derived 3D neural tissues at air-liquid interface

“…Since we can detect action potentials within a very short time (sometimes only several minutes) after tissue placement, we can therefore select tissues which are responding and rapidly discard non-active 3D neural tissues before starting long-term experiments. During the validation process of this new approach, we analyzed different parameters to describe the general neuronal activity, synchronicity, as well as burst structures of multiple spike trains to confirm that the functionality of neural tissues was similar to previous works using different types of MEA devices ( Muzzi et al, 2023 ). In addition, the “embedded” configuration could allow chimeric assemblies which may be of interest, i.e., different tissues being positioned on either side.…”

Rigor and reproducibility in human brain organoid research: Where we are and where we need to go

“…To circumvent these challenges, innovative 3D MEA configurations have been developed to enable more comprehensive activity measurements within organoids ( Choi et al., 2021 ; Shin et al., 2021 ). Comparative studies of organoids on 2D low-density (8x8), 3D low-density (8x8), and 2D high-density (64x64) MEA have shown that 2D high-density MEA are more adept at detecting activity within organoids ( Muzzi et al., 2023 ), suggesting that higher electrode density may offer better suitability for organoid recordings. Emerging MEA platforms, such as mesh nanoelectronics and organoid-integrating scaffolds, promise to facilitate 3D and high-resolution recordings within cortical organoids ( Huang et al., 2022a ; Liu et al., 2020 ; Passaro and Stice, 2020 ; Yang et al., 2024 ).…”