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BP: Fachverband Biologische Physik

BP 30: Posters: Physics of Cells

BP 30.16: Poster

Donnerstag, 17. März 2011, 17:15–20:00, P3

Setup and improvements of dual trap optical tweezers for analyzing the cytoskeleton of epithelial cancer — •Thomas Fröhlich¹, Tobias Paust¹, Michael Beil², and Othmar Marti¹ — ¹Institute of Experimental Physics, Ulm University — ²Department of Internal Medicine I, Ulm University

Optical trapping of dielectric particles is a powerful tool to manipulate and measure biological objects such as cells. Based on acousto-optic deflectors (AODs), quadrant photo diode detection, high speed camera and piezo electric sample positioning, we have built an optical tweezers device for a specially constructed optical microscope. This instrument has two permanent traps. Due to the two axes of the AOD scanning system, one trap can oscillate freely in the image plane and since there are no moving masses, we gain access to a high frequency range. The second trap is adjusted manually with a mirror and is used as a static measure point to gain information about the mechanical properties of the space between the two traps. Becauce of the high performance of the AOD system, it is also possible to get additional traps by time sharing for more complex measurements. To stabilize the system and to minimize the adjustment time, a rail system for the optical components is used.

With this instrument we can manipulate and measure mechanical properties of biological samples in a wide frequency range. The efficiency of this setup was demonstrated with measurements of the dynamic shear modules of the intermediate filament cytoskeleton of pancreatic carcinoma cells.