Functional retinal organoids recorded by a flexible multielectrode array sandwich platform

Stem cell-derived retinal organoids provide a powerful in vitro platform for studying retinal development, degeneration, and therapeutic strategies. However, methods for assessing their electrophysiological function remain limited by the organoids’ 3D structure and fragility. Here, we demonstrate that a flexible multielectrode array (flexMEA) enables stable and flexible dimension recording of activity from retinal organoids. Using a sandwich approach that combines a polyimide-based flexMEA with a standard 60-electrode MEA, we achieved high-quality extracellular recordings and mapped neuronal activity across the organoid surface. In this configuration, the standard MEA was used for electrical stimulation, while neural signals were recorded with the flexMEA. This work is proof-of-the-concept of a flexMEA integrated technology as a non-invasive and conformal approach for functional phenotyping of retinal organoids for the future functional interventions, such as drug testing.