Abstract

Human induced pluripotent stem cell (iPSC)-derived cortical organoids have emerged as transformative in vitro models for studying human neurodevelopment due to their remarkable ability to recapitulate early stages of corticogenesis in a three-dimensional environment. Unlike two-dimensional cultures, cortical organoids exhibit self-organizing properties that enable the formation of neuroepithelial regions, neuronal populations, and glial networks resembling the developing human cerebral cortex. In this study, we established a standardized and reproducible protocol for generating human cortical organoids from iPSCs and performed multiscale structural characterization using confocal microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Human iPSCs were cultured under feeder-free conditions and differentiated through embryoid body formation followed by neural induction and cortical differentiation. Mature organoids were analyzed to evaluate cellular organization, tissue morphology, and ultrastructural maturation. Confocal microscopy demonstrated well-organized cortical-like architecture characterized by uniform nuclear distribution, extensive GFAP-positive astroglial networks, and distinct neuronal cell bodies identified by NeuroTrace staining. SEM analysis revealed spherical organoids with dense and highly organized surface topology, neuroepithelial folding, and neurite-like projections suggestive of progressive neuronal connectivity and tissue remodeling. TEM confirmed neuronal maturation through the identification of well-defined neuronal cell bodies, intercellular junctions, and myelin sheath-like structure surrounding neuronal processes. These findings demonstrate that the generated cortical organoids successfully reproduce essential structural features of early human brain development. The integration of multimodal imaging techniques provides robust validation of organoid architecture and maturation, establishing this platform as a reliable and biologically relevant model for studying neurodevelopment and neurological disease mechanisms. This work further contributes toward the standardization of cortical organoid generation and characterization protocols for translational neuroscience research.

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Funding