The project DILI-on-chip addresses the development of a microfluidic device to assess in vitro adverse drug reactions, on a human-like liver lobule. We will focus on the particular case of DILI (drug induced liver injury). From a unique donor, hiPSCs (human induced pluripotent stem cells) will be differentiated to obtain the different types of cells, hepatocytes as well as non-parenchymal cells, that compose the liver lobule. Hepatocytes forming the hepatic cord, bordered by endothelial cells forming the sinusoid, and cholangiocytes forming the bile ducts will be organized in 3D on the chip, in order to get a functional unit mimicking the Hering channel. Kupffer cells will also be introduced in the vascular channels, as they are involved in the immune aspects of DILI. Multiple hepatic cords will be contained in microfluidic chambers, organized in circular lobule-like structures, and vascularized in order to induce the hepatocyte polarization, and bile canaliculi formation. Bile ducts will be formed in our chip, for the first time, by cholangiocytes maturation at the continuation of the hepatic chamber. Such biliary ways reconstructed on a chip is of prime importance as bile extraction is mandatory for the long term viability required for DILI assays. The microfluidic device will be composed of two parts ; i) a supporting substrate where will be organized the fluidic connections level, with the vascular and biliary flows. This substrate will be made out of Polydimethylsiloxane (PDMS) using the conventional soft lithography techniques or replicated in plastic (PolyMethylMetAcrylate) by hot embossing ii) on the top of this substrate will be assembled cell culture units, made out of polysaccharides gel, that have the suitable stiffness properties near to the one of the liver parenchymatic tissue, and the appropriate porosity for the nutrient and oxygen exchanges. The geometry of the microfluidic circuitry molded in this gel will be optimized in order to induce the tubular self-organization of cholangiocytes and endothelial cells, with the help of specific functionalization of the gel. An important feature of the device is the possible biodegradability of the gel part, that will render possible the collection of cells or cell content, for proteomics or transcriptomic analysis after drug exposure of the organ on chip. The polysaccharide gel structured units will be arrayed on the microfluidic subpart, in order to prove the feasibility of parallelization of the concept, with possible drug screening by the spotting of several drugs at different concentrations on the array, and collection of bile and vascular flows, for toxicology analysis in the context of DILI. Hepatotoxic compounds effects on the organ on chip will be analyzed, characterizing firstly the drug metabolism activity of the cells, then monitoring the damages induced to liver cells. Cumulative mechanisms of DILI will be finally addressed, by the drug exposure to cells presenting pre-existing pathologies. The project is organized in five tasks, including the management task. The tasks 1 will focus of the obtention of the different cells types that will compose the liver on chip, that will be differentiated from Induced pluripotent stem cells (iPSCs) from the same donor. The consortium will benefit from the huge experience of partner 2 in iPSCs cells differentiation. The second task concerns the fabrication of the microfluidic device, combining the expertises of the partners in microfluidics systems fabrication, and in the preparation and patterning of biodegradable gels. Task 3 will be devoted to the cell loading and culture within the device, including the fluidic instrumentation of the experiment. The formation of a functional hepato-cholangiocyte transition will be characterized on the chip in real-time. Finally, the task 4, led by the industrial partner, will focus on the drug assay on the functional liver on chip, in the DILI application context.