Fig. 4.

Contraction ofacentral channelincollagen and Col/Fib gels. A) Outline of channels in PSC-laden collagen and Col/Fib gels for a total duration of 3 days (f.c. = fully closed) based on a custom-made contraction assay (Fig. S5, Supporting Information). Scale bar = 500 μm. B) Contraction of channels in PSC-laden collagen and Col/Fib gels followed for a total duration of 3 days and standardized to the initial days, n = 3. C) Highlighted standardized contraction for 24 h, 48 h and 96 h post-preparation, n = 3. D) Photographic images of the full model (1) prior to crosslinking of the surrounding collagen gel highlighting the central, already crosslinked, Col/Fib gel, (2) after the crosslinking of collagen and (3) after removal of the central sacrificial rod and from the mold, highlighting the different parts of the model. For better visualization of the central Col/Fib gel, a top layer of collagen was not applied for these photographic images. E) Schematic representation of a contracted central endothelialized channel in multi-layered collagen/Col/Fib gels. F) Sections of central endothelialized channel highlighting the monolayer of CellTracker-labelled HUVECs (red) and nuclei (blue) in the collagen and Col/Fib part of a multi-layered collagen/Col/Fib construct 3 days post-formation. Scale bar = 200 μm. G) Quantification of the size of the central channel in the collagen and Col/Fib part of a multi-layered collagen/Col/Fib construct, n = 3. H) SEM images at the intersection of the collagen and Col/Fib part of a multi-layered collagen/Col/Fib construct. Scale bar = 500 μm. Mean + SEM, *p < 0.05, **p < 0.01, ***p < 0.001.