High-precision freeform DLP bioprinting by thermo-reversible gelation

Light-based 3D bioprinting technology can be used to prepare complex hydrogel structures for tissue engineering, but it is limited by reduced precision due to radical diffusion and light scattering, as well as geometric restriction. We propose a reversible gelation suspension stereolithography technique, which combines DLP printing with temperature-controlled reversible gelation, gelling the bioink prior to photocuring. This strategy suppresses diffusion and scattering, achieving 6.8 μm precision, and provides in situ support for suspended structures, overcoming traditional geometric restriction. We demonstrated the feasibility in unrestricted geometry by printing various structures and demonstrated multi-material printing. Cell-loaded hexagonal hepatic lobule bio-inspired structure and multi-scale branched vessels seeded with HUVEC were then constructed, high survival rates and functional performance demonstrated its superior biocompatibility, thereby providing possibilities for new tissue engineering applications.