Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: Poster: Biopolymers and Biomaterials (jointly with BP)
CPP 7.1: Poster
Montag, 26. März 2012, 17:30–19:30, Poster A
Conformation Changes of F-actin under Shear — •Inka Lauter1, Donald Guu2, Minne Paul Lettinga2, Rudolf Merkel1, and Margret Giesen1 — 1Institute of Complex Systems: Biomechanics (ICS-7), — 2Institute of Complex Systems: Soft Condensed Matter (ICS-3); Forschungszentrum Jülich
Polymers have versatile physical characteristics. Besides stiff and flexible polymers, the class of semiflexible polymers is of high interest in rheology as well as in biophysics. In our work we focus on the collective properties of in vitro polymerized solutions of filamentous actin (F-actin). We present recent data on fluorescently labeled single actin filaments in a solution of unlabeled actin filaments under external shear force. The studies were performed by means of a multi-pinhole-confocal microscope and a counter rotating shear cell. We show that under shear, filaments align perpendicular to the velocity gradient. Furthermore we studied filament curvatures as a function of actin concentration. The curvature distribution exhibits an exponential tail and the probability for high filament curvatures increases with actin concentration. The distribution of filament lengths, however, is unaffected even under high shear rates. This result is in contrast to classic rheometer data, which predict filament rupture at a certain strain level.