Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 40: Poster Session II

AKB 40.21: Poster

Wednesday, March 29, 2006, 16:30–19:30, P3

Light scattering measurements on single cells in a dual beam laser trap — •Moritz Kreysing, Kort Travis, and Jochen Guck — Institute for Soft Matter Physics, Universität Leipzig, Linnéstr. 5, 04103 Leipzig

The principle aim of this work is the development of an easy to handle fast working method to measure light scattering properties of single cells in aqueous media. Therefore we made use of the high symmetry of cells lying directly on the axis of a dual beam laser trap. Additionally to the common setup of this trap laser light in the visible range is emitted by one of the fibers, scattered by the cell and is then partly coupled into the opposite fiber. Measuring this recoupled light while varying the position of the cell by modifying the trapping lasers power allows to calculate the scattered light’s intensity as a function of the angle. Comparing this to standards measured with a confocal microscope and models based on Mie theory provides information about average refractive index, size, and deformation of the cell, for example caused by using the setup as optical stretcher. Further insights into the dielectric properties of cell organelles and surface morphology can be obtained. This could eventually be utilized in cell sorting applications.