(594f) Stem Cell Differentiation On Cell-Based Biomimetic Micropatterns

In this work, we examined the effects of restricting human mesenchymal stem cells (HMSCs) to mimic cell shapes adopted by human subcutaneous adipocytes.  We first imaged mature adipocytes cultured in 2-D and used these images to develop protein micropatterns mimicking the shape of these cells for HMSC culture.  Using laser scanning lithography, a versatile maskless patterning technique, we successfully developed arrays of these unique adipocyte-mimetic fibronectin patterns against a biologically inert oligo(ethylene glycol) background.  In addition, we developed arrays of simple geometric shapes, including squares and circles, along with modified fibronectin patterns containing multiple high aspect ratio projections originating from the adipocyte-mimetic patterns.  We then used these patterns to culture HMSCs with a single cell contained within each pattern.  The expression of the transcription factor, peroxisome proliferator-activated receptor-γ (PPAR-γ), which is known to be critical in adipogenesis, was quantified for these cells.  Following 7 days in culture, HMSCs restricted to the adipocyte-mimetic patterns had a 50% greater nuclear to cytoplasmic ratio of PPAR-γ than the modified patterns containing high aspect ratio projections.  In addition, approximately 50% of cells cultured on adipocyte-mimetic patterns expressed lipids indicative of adipogenesis after 7 days, compared to 16% for cells on the modified patterns and approximately 30% for cells on square and circle fibronectin patterns.  Overall, we have determined that cells on the adipocyte-mimetic patterns more favorably undergo adipogenesis compared to the modified and arbitrary shaped patterns.  We are currently examining the role of cytoskeletal tension in promoting adipogenesis on these adipocyte-mimetic patterns.