Liver-on-Chip: An Analysis of Liver Cell Types, Seeding Parameters, and Liver Function Assays

Liver-on-a-chip (LoC) platforms offer promising alternatives to conventional in vitro and animal models for studying hepatic function and drug response; however, wide variability in cell sources, seeding strategies, extracellular matrices (ECMs), and functional assays limits reproducibility. This study reviews reported 2D and 3D LoC systems to identify commonly used liver cell types, seeding densities, ECM materials, and albumin/urea assay methods. Immortalised HepG2-based models dominate current platforms, with optimal seeding densities typically ranging from ~3 × 10⁶ cells/mL in 2D systems and 0.5-5 × 10⁶ cells/mL in 3D constructs. Collagen I, alone or combined with Matrigel, emerged as the most frequently adopted ECM. Functional assessment across studies highlighted albumin and urea as robust markers, with Abcam ELISA and QuantiChrom DIUR assays providing suitable sensitivity for microfluidic sample volumes. Collectively, this work establishes practical benchmarks for hepatic cell selection, seeding parameters, ECM choice, and assay selection, supporting more standardised and reproducible LoC development.