Nanoporous Polyelectrolyte Multilayers: Biomimetic Surfaces for Corneal Epithelial Cells
Christina Hajicharalambous1, Xiaoxia Sheng2, William Hix3, Magdalena Swierczewska1, Michael F. Rubner2, and Padma Rajagopalan3. (1) Bioengineering Program, Lehigh University, Bethlehem, PA 18015, (2) Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, (3) Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
In vivo, corneal epithelial cells are adhered on basement membranes that exhibit topography on the nanoscale with the diameters of pores and fibers ranging from 20 200nm. Polyelectrolyte multilayers with porosity ranging from the nano to the microscale were assembled to recapitulate the porosity and topography in vivo. The average pore diameter was found to be 100nm and 600nm for the nanoporous and sub-micron porous films respectively. In this study, a purely physical feature, specifically, porosity, provided cues to human corneal epithelial cells. Although both nano- and sub-micron porous surfaces were found to be biocompatible and supported cell adhesion, the nanoscale environment enhanced corneal epithelial cellular response. Corneal epithelial cell proliferation and migration speeds were significantly higher on nanoporous topographies. The actin cytoskeletal organization was well-defined and vinculin focal adhesions were found in cells presented with a nanoscale environment. These trends prevailed for fibronectin-coated surfaces as well suggesting that for corneal epithelial cells, the physical environment plays a defining role in guiding cell behavior. Atomic force microscopy measurements of the substrata did not indicate changes in porosity as a result of cell culture.