Microfluidic‐based vascularization strategies: soft lithography (top) and 3D patterning (bottom). a) Liver sinusoid on‐chip fabricated by soft lithography. LSECs and KCs were seeded on the apical side of a PE membrane while HSCs on its basolateral side and HCs on the PDMS substrate (top). Lateral view of the sinusoidal endothelium (bottom): LSECs (green) and KCs (red) on the top and HSCs (yellow) on the bottom of the membrane. Reproduced with permission.[
73
] Copyright 2017, The Royal Society of Chemistry. b) ECM‐based vascularized BBB platform: A) HUVECs and fibroblasts were seeded in the vascular channel (VC), and neural cells (astrocytes and neurons) were seeded in the neural channel (NC). The formation of vascular network in the central vascular network channel (VNC) ensured a direct interface between the capillaries and the astrocytes through astrocytic endfeet (B,C: ECs stained in red, astrocytes stained in white). Adapted with permission.[
66
] Copyright 2017, Springer Nature. c) Skin‐equivalent platform generated by templating: A,B) The culture device was 3D printed and filled with collagen and fibroblasts to form the dermis layer. After removal of the nylon wires, the hollow channel was seeded with HUVECs to form the capillary, and keratinocytes were cultured on the top of the dermis and exposed to liquid–air interface for cornification of the epidermal layer. C) Perfusion of the device via peristaltic pump. Reproduced with permission.[
74
] Copyright 2017, Elsevier Inc. d) Hybrid strategy: 3D printed vascularized proximal tubule model. A,B) The colocalized vascular and renal channels are both 3D printed by using a Pluronic F127‐based fugitive ink within an ECM solution and different designs can be easily printed. C,D) The construct is then seeded with epithelial (green) and endothelial (red) cells. Reproduced with permission.[
75
] Copyright 2019, PNAS.