Abstract
Neural organoids integrated into microfluidic systems are powerful models for studying human brain development, disease mechanisms, and pharmacological responses. Despite substantial progress in generating hiPSC-derived regionalized organoids, reliable functional assessment based on electrophysiological network activity remains challenging. Conventional planar microelectrode arrays (MEAs) primarily record from the organoid surface, missing signals from deeper neurons, while existing 3D MEA approaches often compromise tissue integrity, restrict growth, disrupt cytoarchitecture, or lack scalability. In addition, many microfluidic platforms rely on polydimethylsiloxane (PDMS), which is suboptimal for drug testing due to absorption of hydrophobic compounds.
To overcome these challenges, we developed an organ-on-chip platform that integrates hiPSC-derived regionalized neural organoids with an established microelectrode array embedded in custom glass microfluidic chips (Figure 1). Our MEA-NeuroCHIP comprises nine wells, each hosting a single organoid cultured on a 3D hydrogel matrix. Axons extending through the matrix spontaneously enter neurite-trapping microchannels at the base of each well, enabling high-fidelity extracellular recordings without penetrating the tissue or altering its cytoarchitecture. The glass-based design ensures optical transparency, chemical inertness, and compatibility with pharmacological assays, while the microplate-compatible format supports parallelization and automated handling.
Using this platform, we performed repeated recordings from cortical, midbrain, and spinal organoids across multiple stages of differentiation, up to 12 weeks, as well as over multiple days from the same organoid within the chip. We observed maturation of network activity over development and reliably detected distinct firing and bursting patterns characteristic of each organoid type. Moreover, we demonstrated the platform’s suitability for drug assessment by measuring network-level functional responses to pharmacological GABAergic and glutamatergic modulators, detecting electrophysiological changes with high sensitivity in a human-relevant 3D context. Overall, this glass-based microfluidic MEA technology bridges a critical gap between advanced 3D neuronal models and scalable electrophysiological readouts, providing a robust and translational platform for functional studies and more predictive preclinical drug testing in neurological research.