Reconstituting organotypic 2D microtissue co-cultures via sequential stenciling
In mammalian organisms, native tissue function depends on precise spatial organization down to the cellular level. Reconstituting tissue architectures in 2D in vitro platforms can provide a means to study direct and indirect cell-cell interactions in a variety of tissue contexts while remaining compatible with high-throughput assays and high-resolution live imaging. We combine cost-effective stereolithography leveraging 3D printing with replica molding to stencil spatially defined, multicellular culture systems with sub-millimeter resolution onto planar substrates. The system is designed for ease of use, requires no complex fabrication setups and scales readily to 96-well plates. Sequential stencil application and removal under a biosafety cabinet enables controlled positioning of multiple cell types and supported the maturation of tissue assemblies. We demonstrate the utility of this stencil-based patterning strategy in three applications. First, we employ a combination of two circular stencils to recreate a structural feature characteristic for the tumor microenvironment of solid tumors: the encapsulation of colorectal cancer cells by cancer-associated fibroblasts. Resulting cell patternings reproduce native tissue dynamics of the densely packed tumor tissues, in which cancer-associated fibroblast cells actively compress the cancer cells and confer targeted therapy resistance. Second, we probe the synthetic, diffusible morphogen system synNotch in patterned cell patches, where GFP-releasing cells generate a ligand-dependent gradient. Third, we recapitulate the characteristic crypt-villus architecture of the mammalian intestine by patterning intestinal organoids within a stencil-restricted crypt region and allowing differentiating cells to collectively migrate along a designed villus axis. The presented strategy allows for rebuilding multicellular tissue architectures in vitro with biologically relevant spatial precision for high-throughput drug screenings and dissection of tissue-specific cellular interactions.