Figure 2

The microfluidic platform is conducive to the development of human microvessel networks. (a) Perfusable three-dimensional microvessels are generated using an optically clear polydimethsiloxane microfluidic-based platform, (b) consisting of two fluid-filled microfluidic channels on either side of 12 mm diamond-shaped tissue microchambers. Scale bar = 500 μm. The fluidic channels loop down and connect with each diamond through a single 30 μm diameter pore that represents the only port for transport of nutrients and waste. A coculture of endothelial colony-forming-derived endothelial cells and normal human lung fibroblasts are mixed with fibrin matrix or another blend of extracellular matrix and microinjected into the central tissue chamber and allowed to gel. By 14 to 21 days, a robust network of microvessels develops. (c) Fluorescent microscopy of CD31-stained (green) microtissues at 18 days depicts an interconnected network of vessel in a porcine cardiac-derived extracellular matrix blend. Scale bar = 200 μm. (d) Vessel patency and perfusion is verified by introducing microspheres (red, white arrows) into the fluidic channels and observing their movement through the network. Scale bar = 200 μm. (e) A third cell type, such as tumor or cardiomyocyte spheroids, can also be added to the tissue chamber to create specific microorgan systems. Cardiomyocyte spheroids (cTnT, red) remain viable over 29 days in the microfluidic device as the vessel network (CD31, green) develops in the surrounding tissue. Scale bar = 100 μm. (f) Tumor spheroids (black arrows) from colorectal cancer cell line SW620 (transduced with Wnt-regulated GFP reporter cassette) proliferate and increase significantly in total mass at the same time as the continuous vessel network develops, especially between day 10 (inset) and day 20. Scale bar = 500 μm.