Multimodal Neruonal Function Monitoring of hiPSC-Derived Organoids on In Vitro Platform

Neuron-on-a-Chip technology has been intensively studied in medical and pharmaceutical fields to understand and explore complex neurological systems in a controlled in vitro platform. This platform provides a biocompatible cell culture dish with multiple electrodes that can transmit bioelectrical signals and well for nourishing, guiding, and proliferating the neurons. Recently, many researchers studied and investigated three-dimensionally cultured organoids derived from human induced pluripotent stem cells (hiPSC) in in vitro systems. The organoids showed much similar behavior to in vivo systems than 2D cultured cells due to their capability of mimicking organ cell formation with cell-to-cell interaction. However, due to their self-organizing characteristics while development and proliferation, the design of the multielectrode array (MEA) and microfluidic channels should be considered an important factor in realizing practical preclinical models.<br/>In this paper, we developed a MEA chip consisting of a total of 130 electrodes that each can act as an electrically stimulating or recording site and dumbbell-shaped microfluidic channel to investigate hiPSC-derived motor nerve organoids placed in two wells. To minimize the contact impedance of the electrodes, the opening area (9 um diameter) is covered with platinum black. The organoids were cultured for one month in vitro and organoid formation and axon growth were investigated. The results showed that the axons from the organoids extended ~3 times longer in narrow fluidic channel (300 um width) than inside the well (2 mm diameter). Developed MEA chip showed simultaneously detection of multiple neuronal activities with a low background noise level. Also, from the electrical stimulation tests, neuronal network activities including conduction behavior were measured and analyzed. Further improvements to the MEA chip including 3D shaped electrode array and microfluidic channel variation may provide a basis for an advanced preclinical model platform for regenerative medicine and human disease modeling in the future.