A modular silk-collagen scaffold to model dorsoventral spinal cord organization using human pluripotent stem cells

In vitro tissue models are critical to our understanding of human cell functions and interactions, but their limited complexity can hinder translation to in vivo systems. Bioengineered 3D tissues are gradually improving the capabilities of in vitro models, but the highly complex spatial organization of the human central nervous system (CNS) represents a particular challenge. Many 3D CNS models are limited to single cell types, while multicellular models generally lack control of cell organization, failing to recapitulate the regional specificity of cells in vivo. Using the dorsoventral spinal cord axis as a representative system, we generated a modular 3D silk-collagen protein composite scaffold system for the co-culture of dorsal (sensory) and ventral (motor) spinal cord progenitors in spatially discrete regions. Imaging showed the differentiation and maturation of both cell populations in distinct compartments, while bulk RNA sequencing confirmed the presence of combined motor and sensory markers in dorsoventral co-cultures, suggesting the potential for enhanced biological function in vitro. While developed for spinal cord modeling, our fabrication approach is generalizable to other tissues and regions of the CNS, enabling spatial control of multiple tissue compartments. We anticipate that long-term culture with added supportive cell types will foster greater complexity and open avenues for future functional and translational applications.