Figure 3.

Commonly used models of endothelial lumens embedded in a hydrogel. (A-D) Two parallel luminal structures cast within a hydrogel using needles. (A) Schematics of the device showing two parallel lumens. One lumen is lined with endothelial cells and the other used as a source for angiogenic growth factors. (B) Representative images of the device and a cultured vessel. F-actin is stained with phalloidin in green and nucleus with DAPI in blue. (C-D) Confocal images of angiogenic sprouting in response to different cocktails of angiogenic growth factors, HFMVS and MVPS. F-actin (phalloidin, green), nuclei (DAPI, blue). Scale bars are 100 μm. (E-H) A single luminal structure embedded in a hydrogel generated using flexible PDMS rods with variable structures as templates. (E) Schematic of LumeNEXT device construction and operation. (F) Cultured vessels respond to VEGF stimulation and sprout in the direction of the source (F-actin, red). (G) Vessels have circular cross-sections. (H) Demonstration of non-linear geometries achievable with the method. (I-K) Blood-brain barrier and in vitro microvascular network model. (I) Schematic representation of the blood-brain barrier (BBB), composed of brain Endothelial cells (ECs) vessels overlapped by pericytes (PCs) and astrocytes (ACs). (J) Schematic representation of proposed 3D BBB microvascular network (μVN) model that mimics the microvascular structure present in the brain environment. (K) Confocal image of self-assembled BBB μVN model including iPSC-ECs (CD31, green), PCs (F-actin, red) and ACs (GFAP, magenta), and nuclei (DAPI, blue) ^{29, 32, 206, 226}. Copyright (2013) National Academy of Sciences for top-right images, ref 32. Reproduced from ref. 226 with permission from Elsevier Science & Technology Journals, copyright 2017.