Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 5: Posters: Biopolymers and Biomaterials
BP 5.30: Poster
Montag, 22. März 2010, 17:15–20:00, Poster B1
Dynamic measurement of the persistence length of intermediate filaments — •Bernd Nöding, Susanne Bauch, and Sarah Köster — Courant Research Centre Nano-Spectroscopy and X-Ray Imaging, University of Göttingen, Germany
The eukaryotic cytoskeleton, which is responsible for the mechanics of the cell, mainly consists of three types of fibrous proteins. While microtubules and microfilaments are highly conserved, intermediate filaments (IFs) vary from cell type to cell type. Here, we focus our study on vimentin, which occurs in cells of mesenchymal origin. Investigations of mechanical properties of individual filaments are a necessary prerequisite for a better understanding of the mechanics of biopolymer networks and eventually whole cells. The mechanical rigidity of a polymer is characterized by its persistence length Lp. In the case of vimentin, Lp was found to be on the order of one µ m using atomic force and electron microscopy. However, in both cases the filaments need to be adhered to a substrate. Our aim is to perform dynamic measurements of filaments in solution without any interaction with a substrate whatsoever. To this end we fluorescently label the filaments and confine them in microchannels with a width of about one µ m, thereby realizing the Odijk confinement regime. The contour of the filaments is imaged by epi-fluorescence microscopy. The purpose of the channels is twofold: the filaments are prevented from coiling and they are restrained to a single focal plane. Since IFs can be classified as semiflexible polymers we assume the worm-like-chain model for our fluctuation analysis. The channel walls are included as parabolic potential in our model.