Topological tracks patterned via 3D printing vascularize murine organ-scale constructs

Engineered tissues could one day offer critical therapeutic relief for those requiring whole-organ transplantation. Yet, their translation remains hindered by the need for robust vascularization throughout tissues of organ-scale sizes. Here, we used selective laser sintering of sacrificial isomalt templates to pattern vascular-promoting "tracks" across murine organ-scale tissue constructs. Upon implantation in mice, the patterned tracks architecturally guided host-mediated vascularization within fibrin and gelatin methacrylate/methacryloyl (GelMA) constructs. Whereas the inclusion of tracks improved the vascularization response within both matrices, GelMA constructs demonstrated greater implant stability after 1 week in vivo . Subsequent implantation of GelMA constructs that were densely cellularized generated widespread, volumetric circulatory integration via both track-guided and self-assembled new blood vessels. This platform enables the generation of vascular networks spanning large, engineered tissues that can fully integrate with host circulation and represents a significant step toward the development of clinically translatable organ-scale tissues.