(678c) Directing Cell Behavior On Biologically Inspired Micropatterned Surfaces

Intracellular and extracellular forces influence cell behavior, including migration, proliferation, and differentiation.  Focal adhesions anchor the cytoskeleton to the surrounding extracellular matrix and transmit and respond to these forces, thereby regulating cytoskeletal tension.  By restricting the focal adhesions formed by a cell, we may be able to control cell behavior.  In this work, we have attempted to recapitulate complex cellular adhesion site configurations using laser-scanning lithography (LSL), a maskless micropatterning technique.  We first examined whether differences in adhesion site properties, including size, shape, and density, exist for various cells of mesenchymal origin, including adipocytes and osteoblasts.  We found that more than 80% of focal adhesions in both cell types had a circularity of greater than 0.7, while there were significant differences in the focal adhesion density and size.  There were 5 times as many adhesions per cell area in adipocytes compared to osteoblasts, where approximately 79% and 93% of these adhesions were less than 1.0 μm² in adipocytes and osteoblasts, respectively.  We have successfully used LSL to produce two-dimensional fibronectin patterns that mimic the different adhesion site configurations of both osteoblasts and adipocytes with great accuracy.  We are now using arrays of these patterns to culture human mesenchymal stem cells in attempts to optimize lineage commitment in these cells.