Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 24: Cell Mechanics (in vivo)

BP 24.10: Talk

Thursday, March 29, 2007, 12:30–12:45, H44

Beyond the Rim: The Viscoelastic Pericellular Coat — •Heike Boehm, Joachim Spatz, and Jennifer Curtis — Max-Planck-Institute for Metals Research, Department New Materials & Biosystems & University of Heidelberg, Department of Biophysical Chemistry

Most mammalian cells are surrounded by an optically-transparent layer of highly hydrated polysaccharides and proteins, the pericellular coat (PCC). The most vital component is a linear, flexible polyelectrolyte: hyaluronan, which is synthesized directly on the outer cell membrane. Different proteins can bind to the hyaluronan and thus anchor it to the cell membrane, stiffen and/or crosslink it. The resulting viscoelastic coat plays a vital role in cell migration, proliferation and various diseases like cancer and arthritis.

Few studies quantitatively examine the PCC's mechanical properties induced by structural or compositional reorganization. We perform microrheology studies to determine the viscoelasticity and define the impact of proteins and glycosaminoglycans on the structure of the PCC. Information about the structure of the polymer matrix can thus be gained by observing the diffusion of a particle embedded in the PCC of living cells (passive microrheology). With our holographic optical tweezers (HOT) setup we can create a dynamic array of traps, that enable us to carefully place several beads at different sides of a living cell simultaneously and to measure or apply forces ranging from femtonewtons to 10's of piconewtons (active microrheology).