Suspended Tissue Engineering with Assemblable Microfluidics (STEAM)

Suspended tissue culture systems enable cellular responses to mechanical forces critical for tissue development and function. Tissues develop in a complex environment containing both mechanical and chemical cues that vary spatiotemporally; modeling both of these physiochemistries in vitro through integration of spatial patterning with mechanical manipulation is thus an important aspect in microphysiological tissue modeling. Here we introduce Suspended Tissue Engineering with Assemblable Microfluidics (STEAM), a modular tissue fabrication platform that allows for spatially heterogeneous suspended tissue architectures. With STEAM we achieve tissue constructs with multiple regions through the addition of capillary pinning features to control hydrogel precursor flow. STEAM tissues can easily be moved from patterning setup to well-plate to microscope slide, and enables stacking of separately generated layers. Mechanical manipulation post-fabrication is also possible via static stretching, where cell-embedded 3D tissues can be stretched farther apart to induce strain along an axis. To demonstrate this post fabrication strain ability, we induced strain in mouse myoblasts in an engineered muscle tissue model that increased alignment of myotubes. Finally, by modifying the channel geometry of the fluidic based patterning rails, we generate complex nonplanar suspended tissues. Overall, STEAM leverages microfluidic principles to generate suspended tissues that integrate patterning precision, mechanical functionality, and experimental versatility. STEAM provides a suite of tissue constructs for modeling tissue behaviors from the interplay of spatial organization and mechanical forces.