Shear‐Extensional Aspect Programming of Microgels (SHAPE)

ABSTRACT Microgels of various shapes are on great demand for diverse biomedical applications. We present a fluid‐based strategy for sculpting interfacial morphologies in all‐aqueous dual‐phase systems by tailoring flow‐field geometry. Through combined experiments and simulations, we uncover how the inlet and outlet geometry governs the discrete phase deformation, offering a clear picture of interface evolution and its underlying mechanisms. We can thus shape spherical microgels into diverse non‐spherical shapes—including microrods, microfibers, and microribbons—with tailored aspect ratios. The methodology supports a wide range of hydrogel materials and enables the integration of living cells. The microgels fabricated by this method can be applied to formulate either sacrificial templates or granular hydrogels. The sacrificial capillary‐fiber‐templated porogel approach promotes the capillaries' formation by leveraging the topographical cues. Cell infiltration into granular hydrogels with different shapes also demonstrates their potential for in vivo applications. Overall, our work establishes the principles of fluid‐directed interfacial control under significant shape deformation in all‐aqueous phase systems, establishing a new approach for the advanced design and fabrication of non‐spherical microgels.