Fig. 3.

(a) Strategies to vascularize organ-on-chips: (i) Facilitating confluent endothelial vessel formation covering the microfluidic channel by gravity-assisted adhesion to hydrogel and dynamic flow, (ii) Endothelial lining at the interface of tissue epithelium separated by a membrane in the middle, (iii) Incorporation of endothelial cells along with supporting matrix, and angiogenetic factors to allow natural sprouting. (b) Vascularized hepatic spheroids-on-chips: (i) OrganoPlate Graft (Mimetas) having an open-top chamber to introduce hepatic spheroid on pre-vascularized beds, (ii) The hepatic spheroid was stained with albumin (green) and microvessels were stained with CD31 (red) (Scale bar: 200 μm), (iii) The functionality and integration of vascular network were validated with perfusion of FITC-dextran through the left channel and retrieving solution from the right channel (shown by dotted ellipse). (c) primary sclerosing cholangitis-on-chip: (i, ii) Vascular and bile-duct on chip to study primary sclerosing cholangitis (VE-cadherin (red) shows endothelial cells, fibroblasts are shown in magenta, and cholangiocytes stained with Keratin-19 (green)) (Scale bar: 200 μm), (iii) Immune cells migration from the vascular channel (tracked in green), (iv) Quantification of enhanced migration of PBMCs from vascular channel under IL-17A stimulation (one way ANOVA or ANOVA on RANKs, Mean ± SD, n > 3 devices) ((E): endothelial cells, (C): cholangiocytes, (F): fibroblasts). Panel (b) is adapted under terms of the CC-BY license from Ref. [77] Copyright 2022, Springer. The device design in panel (b–i) was redrawn for better clarity and resolution. Panel (c) is reproduced under terms of the CC-BY license from Ref. [79] Copyright 2023, IOP science. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)