Berlin 2005 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 100: Poster Session I
AKB 100.2: Poster
Samstag, 5. März 2005, 16:45–18:45, Poster TU D
Thermal Fluctuations of Individual Semiflexible Polymers in Confined Geometry — •Sarah F. Köster1,2, Stephan Herminghaus1,2, Myung C. Choi3, Cyrus R. Safinya3 und Thomas Pfohl1,2 — 1Department of Applied Physics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany — 2Max Planck Institute for Flow Research, Bunsenstraße 10, 37073 Göttingen, Germany — 3Materials Research Laboratory, University of California, Santa Barbara, CA 93106, USA
Thermal fluctuations of individual actin filaments in confining microchannels fabricated by soft photolithography are studied by means of fluorescence microscopy. The channel dimensions are in the same order of magnitude as the mesh size of the actin cytoskeleton within the eukaryotic cell and thus mimic the native environment of the individual filament. We observe a strong dependence of the tangent correlation upon both the channel geometry and the filament length. Compared to freely fluctuating filaments, long filaments confined in narrow channels exhibit an enhanced tangent correlation revealing a local minimum and an oscillatory behavior. We also observe a clear deviation from existing theoretical models on small length scales, assumedly due to an intrinsic stiffness of the semiflexible chain. These unique characteristics may be qualitatively described by an analytical expression considering the bending energy as well as the confining energy assumed as a parabolic potential. We find the scaling law for the deflection length which has been reported before experimentally confirmed.