Microfluidic hydrostatic deposition patterning for a confined hepatocyte-biliary epithelial cell co-culture system

Reconstruction of hepato-biliary networks is very important to maintaining liver organoids in vitro, since the accumulation of bile has been proven to be toxic to hepatocytes, especially in long-term culture. We have developed culture methods for reconstructing bile canaliculi (BC) and bile ducts (BDs) formed by small hepatocytes (SHs) which are hepatic progenitor cells, and biliary epithelial cells (BECs), respectively. To study the mechanism of biliary excretion, we need to establish a co-culture system for SHs and BECs. A limitation of conventional culture methods in investigating the mechanisms of hepato-biliary connections is the difficulty to observe the dynamic interactions between SHs and BECs in culture. In addition, patterned constructs do not form in conventional cultures due to the lack of organization of cells. A system that allows more complex dynamics between SHs and BECs to occur is needed in order to investigate the interactions between these cell types. Here, we present an approach called Microfluidic Hydrostatic Deposition Patterning (MHDP) that patterns SH and BEC colonies with defined shape and position, which promotes productive interactions between the cells and eventually induce the formation of heterogeneous tissues integration which is thought to be a prototype of complete biliary networks.