Technical Note Engineering micropatterned surfaces for the coculture of hepatocytes and Kupffer cells Yekaterina S. Zinchenko, Robin N. Coger Mechanical Engineering Department, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, North Carolina 28223 Received 18 November 2004; revised 9 March 2005; accepted 10 March 2005 Published online 28 July 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jbm.a.30399 Abstract: Bioartificial liver (BAL) devices are used for ap- plications 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 under- stand 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 vari- ous 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 charac- terization of the resultant micropatterns, as well as morpho- logical and functional results are also presented. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 75A: 242–248, 2005 Key words: hepatocytes; Kupffer cells; PDMS; micropattern- ing; surface characterization INTRODUCTION One strategy for temporarily extending the lives of patients with liver failure is the use of bioartificial liver (BAL) support devices. These three-dimensional struc- tures are able to perform many of the functions of the natural liver, and have hepatocytes, the parenchymal cells of the liver, as their chief functional component. The ability to maintain differentiated hepatocytes function within BALs is one current challenge. Recent studies suggest that communication between hepato- cytes and nonparenchymal liver cells serves to en- hance liver function in vitro. 1,2 To understand how such interactions can be favorably utilized in BAL design, it is necessary to establish a culture environ- ment that permitted the controlled interactions of multiple cell types. This can be achieved with the use of in vitro micropatterning techniques, as they enable the relative placement of hepatocytes and nonparen- chymal cells to be controlled. The incorporation of micropatterning within tissue- culture systems has been well documented in the lit- erature. In work with hepatocytes and fibroblasts, Bhatia and coworkers described a microfabrication technique for modifying glass substrate with bioma- terials, which allowed them to achieve micropatterns of 20-m thicknesses. 1,3 Folch, Toner, and coworkers extended that work to the use of deep elastomeric microchannels, 4,5 and poly(dimethylsiloxane) (PDMS) elastomeric stencils 6 to micropattern the cells. A mod- ification of the latter method of providing “patterned access to the surface” was briefly mentioned by Whi- tesides and coworkers, 7–9 but no description of the technical details or the required materials was in- cluded. In the current study a variation on this idea is developed—where the details of preparing the PDMS stencil, a method for evaluating the reliability of its fabrication, and its usage in vitro are all described. Specifically, this investigation describes a PDMS membrane-based micropatterning technique for cocul- turing hepatocytes with Kupffer cells for the goal of improving hepatocyte function. Kupffer cells were cho- Correspondence to: R. N. Coger; e-mail: Rncoger@uncc.edu Grant sponsor: NIH; grant number: 1R 01 DK 58503 Grant sponsor: Whitaker Foundation; grant number: RG- 01-0343 © 2005 Wiley Periodicals, Inc.