Controlled Desiccation of Preprinted Hydrogel Scaffolds Toward Complex 3D Microarchitectures

Abstract Additive manufacturing (AM) is the key to creating a wide variety of 3D structures with unique and programmable functionalities. Direct ink writing is one of the widely used AM technologies with numerous printable materials. However, the extrude‐based method is limited by low fabrication resolution, which is confined to printing macrostructures. Herein, a new AM strategy is reported, using a low‐cost extrusion 3D printer, to create 3D microarchitectures at the macroscopic level through controlled desiccation of preprinted hydrogel scaffolds followed by infilling objective components. A printable hydrogel with a high‐water content ensures maximum shrinkage (≈99.5% in volume) of the printed scaffolds to achieve high resolution. Stable covalent cross‐linking and a suitable drying rate enable uniform shrinkage of the scaffolds to retain their original architectures. Particularly, this method can be adapted to produce liquid‐metal‐based 3D circuits and nanocomposite‐based microrobots, indicating its capability to fabricate functional and complex 3D architectures with micron‐level resolution from different material systems.