Figure 5. In vitro culture systems for hepatocytes.

Improved in vitro systems have been developed for culturing primary human hepatocytes. Elucidating the roles of many microenvironmental signals in governing hepatocellular processes has enabled optimization of in vitro culture systems. These optimized systems include co-cultures to provide specific cell-cell interactions as well as culture conditions with defined concentrations of soluble factors and extracellular matrix molecules (left). The application of microfabrication technologies to in vitro hepatic tissue engineering has facilitated the control of culture platforms down to the microscale, such as the patterning of co-culture configurations (middle). Further, natural and synthetic biomaterial systems have been applied towards the optimization of three-dimensional in vitro culture platforms (right). Collectively, these engineering approaches have further advanced the understanding of how combinations of microenvironmental cues influence cell functions, and provided important insights into the temporal and spatial dynamics of hepatic cell and tissue function.