Abstract
[Introduction] Overcoming diffusion limitation is a big challenge in tissue engineering of three-dimensional (3D) organs such as liver. Liver has a complex structure consisting of several cell types, and has microvascular networks that supply cells with oxygen and nutrients. It is therefore important to investigate the mechanism of tissue vascularization to construct 3D organs. [Methods] In this study, 5-channel microfluidic devices were used to culture hepatocytes and endothelial cells. This device has 3 cell culture channels and 2 gel channels between them. We analyzed the interaction between hepatocytes and vascular networks. [Results and Discussion] First, hepatocytes were seeded via one channel, and then interstitial flow across gel scaffolds was applied, resulting in the modification of gel with factors secreted from hepatocytes. Thereafter, endothelial cells were seeded via another channel. This co-culture condition induced extension of vascular networks in a gel scaffold. This extension of vascular networks were also observed when hepatocytes were killed to eliminate secreted factors. Furthermore, a vascular network contacted with a 3D hepatocyte tissue was cultured when hepatocytes were added to the third channel.
