One strategy for temporarily extending the lives of patients with liver failure is the use of bioartificial liver (BAL) support devices. The functional components of BALs are the parenchymal liver cells known as hepatocytes. One design option for further improving current BAL performance levels is to include the non-parenchymal cells of the liver (e.g., Kupffer cells) in the design. In the current study, the effect of Kupffer cells on hepatocyte function was investigated using micropatterned co-cultures of these two liver cell populations. With traditional co-culture methods, the user is unable to control the relative proximity of one cell type to another. In this study, two different micropatterning techniques were used to engineer macro and fine micropatterned configurations for evaluating hepatocyte-Kupffer cell co-cultures. The ratio of one cell population to the other was also adjusted to evaluate the effects on hepatocyte function. The micropatterned co-cultures were maintained for ten days to evaluate for morphological and functional (e.g., albumin, urea) changes. The results illustrate that micropatterning hepatocytes, in the arrangements of this study, significantly improved hepatocyte function.

Establishing suitable oxygen transport pathways within bioartificial liver replacement devices continues to be an important engineering challenge. Oxygen delivery is critical since this is one of the nutrients necessary to maintain hepatocyte viability and function. In the current study, the microporosity of a collagen extracellular matrix has been modified to permit both diffusion and convection mass transport. Using fluorescent visualization, the enhancement technique was found to extend the oxygen transport distance from 170 microns to 360 microns. Furthermore, in hepatocyte culture studies, the enhancement technique was observed to yield a sixfold increase in the amount of viable hepatocytes able to be sustained by a single O2 source. Normalized function studies confirm that hepatocyte function was also improved in the enhanced collagen configurations.

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Bioartificial liver (BAL) devices are used for applications ranging from pharmaceutical testing to temporary liver replacement. The capabilities of these devices can be improved by optimizing the range of hepatocyte functions that the BAL is able to perform. One means of achieving this is to design the BAL such that it establishes communication between hepatocytes and nonparenchymal cells. To understand how these heterotypic interactions can be favorably utilized in BAL design, it is first necessary to establish a culture environment that permits the controlled interactions of multiple cell types. This is the goal of the current study, which focuses on micropatterned cocultures of hepatocytes with Kupffer cells. The micropatterning technique relies on a polydimethylsiloxane (PDMS) membrane to achieve various two-dimensional configurations of the ECM prior to seeding the cell populations. The easy and inexpensive method of making the PDMS membranes differs from that reported in the literature and is detailed in the current study. To demonstrate the success of the method, surface characterization of the resultant micropatterns, as well as morphological and functional results are also presented.