Liver-on-a-chip cell culture devices are attractive biomimetic models in drug discovery, toxicology and tissue engineering research. To maintain specific liver cell functions on a chip in the lab, adequate cell types and culture conditions must be met, which includes 3D cell orientation and a consistent supply of nutrients and oxygen. Compared with conventional 2D cell culture techniques, organ-on-a-chip devices offer versatility and effective biomimicry suited for advanced applications in drug discovery and medicine.