Abstract
Reconstituting organ development in vitro requires reproducing dynamic developmental transitions rather than only terminal tissue structures. Here, we developed MoSAIC (Modular Spatial Assembly and Integration of Cues), a modular platform that decomposes complex culture operations and subsequently integrates them to reconstruct multimodal mechano-chemical spatial cues. Using human induced pluripotent stem cells, MoSAIC enabled independent control of tissue geometry, extracellular matrix localization, physical boundaries, and morphogen gradients, while also permitting defined mechanical and chemical perturbations during development. Their integration guided a continuous ectodermal sheet through neural induction, tissue bending, and bifurcation into neural and epidermal tissues, followed by formation of a polarized neural tube structure. Spatially controlled morphogen exposure further established dorsoventral patterning, while the resulting tissue exhibited posterior neural tube identity. Using the developed model recapitulating the transition of human neurulation, MoSAIC further enables non-genetic perturbation of mechanical and chemical cues to interrogate the mechanisms governing neural tube closure.