Fig. 1. Bioprinting endothelialized vascular beds with complex geometry.

(A) Schematic representation of vascular bed printing using the sacrificial ink method. (B) Cytoskeletal morphology of microvascular endothelial cells shows high alignment in straight regions of the vascular bed (inset i, red border), with chaotic cytoskeletal alignment in the fork regions (inset ii, blue border). (C) Alignment of cytoskeleton (scale of 0.5 for randomly aligned to 1 for perfectly aligned) in perfused engineered beds shows high actin alignment in the wall of straight vascular regions (yellow arrows), whereas fork regions exhibit weak alignment (blue arrows). AU, arbitrary units. (D) Direction of preferential alignment follows flow direction. Colored arrows indicate principle flow direction (up, yellow; down, purple), which tends to agree with orientation direction of endothelial cell alignment.