Embedding Perfusable Microchannel Networks in Photoclickable Bioresins via High-Resolution Digital Light Processing

Light-mediated 3D bioprinting methods hold great promise for the generation of biomimetic microvasculature networks for applications ranging from organ-on-chip models to vascularized tissue constructs. While printing microvascular channels (≤100 um in diameter) within large hydrogel volumes (≥1 cm^3) is theoretically feasible, progress remains limited by the lack of suitable biocompatible photoresins. Here, we report the development of an optimized photoresin based on fish gelatin and photoclick crosslinking chemistry for bioprinting perfusable, embedded microvascular networks via high-resolution digital light processing (DLP). Specifically, our biocompatible matrix leverages the fast kinetics and negligible dark curing of thiol-norbornene crosslinking as well as the low viscosity and thermal stability of fish gelatin. Using pulsed illumination and a biocompatible radical scavenger (DMPO), we further minimize radical diffusion-induced blurring, enabling extended printing (>5 h). Finally, printing failures are reduced through the incorporation of a biocompatible surfactant (Poloxamer-188). Together, these advances open new avenues for printing perfusable biomimetic microvascular networks embedded in biocompatible hydrogel matrices.