Suspended Tissue Engineering with Assemblable Microfluidics (STEAM)

Abstract

Suspended tissue culture systems enable cellular responses to mechanical forces critical for tissue development and function. Tissues develop in complex environments containing both mechanical and chemical cues that vary spatiotemporally; thus modeling both of these physiochemistries in vitro through integration of spatial patterning with mechanical manipulation simultaneously is an important aspect in microphysiological tissue modeling which has yet to be achieved. 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, which also 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 the utility of post fabrication strain ability, we showed that myotube alignment increases when strain is applied to STEAM generated engineered muscle tissue containing mouse myoblasts. Finally, by modifying the channel geometry of the fluidic-based patterning rails, we generate complex nonplanar suspended tissues. STEAM leverages microfluidic principles to generate suspended tissues that integrate patterning precision, mechanical functionality, and experimental versatility, providing a suite of construct combinations for modeling tissue behaviors from the interplay of spatial organization and mechanical forces.