Regensburg 2004 – scientific programme

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.8: Poster

Friday, March 12, 2004, 10:30–13:00, B

Fibronectin fiber formation by surface tension on microfabricated pillar interfaces — •Jens Ulmer, Stefan Graeter, Wouter Roos, and Joachim Spatz — University of Heidelberg, Institute for Physical Chemistry, Biophysical Chemistry,

The extracellular matrix (ECM) provides positional and environmental information for cells which are essential for tissue function. ECM proteins such as fibronectin (FN), laminin or collagen form distinct protein networks in vivo that show tissue-specific variation in composition and architecture. In vivo, FN-matrix assembly is mediated through integrins which bind FN for forming cell-ECM contacts. FN molecules are then stretched by cell generated forces. This causes conformational change in FN molecules and enables FN from solution to bind. Thus, fibrillogenesis of FN is stimulated and directed by force. We mimicked this force induced FN assembly into fibers in vitro by stretching surface bound FN molecules through water surface tension appearing between the surface of a water drop and the tops of microfabricated pillars. Microfabricated pillar arrays offer binding points to the ECM molecules which then bridge the pillars tops by fibre network formation. In addition, micropillar interfaces are sensitive force sensors which allow quantitative access to the fiber formation process. The architecture of the resultant structure showed to depend on concentration of the FN-solution and to be mediated by forces generated from water surface tensions. Subsequently, the defined FN-networks offers guiding cues for cell-ECM interactions.