Microrobotic Assembly of Shape-Customized Three-Dimensional Microtissues Based on Surface Tension Driven Self-Alignment

Engineered microscale tissues that replicate in vivo architectures have shown huge potential in drug discovery and regenerative medicine. This letter reports a microrobotic assembly method to fabricate three-dimensional (3-D) microtissues reproducing arbitrary morphologies of native tissues. Cell-laden micromodules are photo-crosslinked with cell-mixed hydrogel, which can be formed into customized shapes embedding circular lumen. The micromodules are sequentially picked up and spatially reorganized as a 3-D microarchitecture with the hydrodynamic interaction. In the interaction, all the micromodules are driven by the surface tension between water-oil multiphase, which simultaneously aligns both the geometric outline and lumens of micromodules to mimic the morphology and vessel-mimetic hollow structure of native tissues. As the driven force is proportional to the surface area of the micromodules exposed to the oil, the shape design parameters of micromodules are optimized to achieve accurate self-alignment of the microtissues. We anticipate that our method will regenerate complex tissues with physiological importance in future tissue engineering.