Dimethyl sulfoxide mediated high-fidelity 3D printing of hydrogels

Owing to flexible structural design and rapid prototyping manufacturing, 3D printable hydrogels with solid-like and fluid-like characters have emerged as a promising candidate for biomedical engineering, soft robotics, and flexible electronics. However, existing 3D printing of hydrogel place substantial constraints on hydrogel highfidelity of the printed hydrogel complex structures due to the shape deformation and collapse caused by water evaporation. Herein, we propose a mixed solvent printing strategy followed with water dialysis to achieve vat photopolymerization 3D printing of high-fidelity hydrogel structure by restraining water evaporation. Concretely, dimethyl sulfoxide (DMSO) is introduced into the hydrogel ink as co-solvent to improve the antidehydration performance during 3D printing. The as-prepared gels are then transformed into hydrogels with good fidelity and excellent performance through solvent exchange and water dialysis. Enabled by these characteristics, various functional devices with complex structures are demonstrated with the present high-fidelity 3D printing of diverse hydrogels. The solvent assisted high-fidelity hydrogel 3D printing protocol combining with the compatibility to various high-performance hydrogels is believed to be promising for wearable devices, wound dressings, electronic skin, and intelligent robots.