Crystal Transduction 3D Printing of Bio-Hydrogels with High Fidelity and Order Micro Pores

3D printing of bio-hydrogel scaffolds are widely used in tissue regeneration. However, due to the ultra-soft properties of bio-hydrogels, it is hard to print them precisely. Here, crystal transduction 3D printing with high fidelity is proposed to address this challenge. A phase-transition bio-inks system with beeswax is developed for crystal transduction, which can accelerate energy consumption and induce soft bio-inks to quickly harden during printing. Interestingly, an interconnected porous hydrogel scaffold can be obtained after washing the crystal beeswax. The porous hydrogel scaffold demonstrated excellent biocompatibility and cell proliferation effect in vitro and is free from defense responses and immunogenicity in vivo. Muscle analog porous scaffolds constructed by high-fidelity 3D printing significantly improve the tissue function recovery of rats with muscle defects, compared with the conventional printed hydrogel with a non-matched shape. These structure-performance design rules create exciting opportunities to customize 3D-printed porous hydrogel scaffolds with high fidelity.