Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 18: Posters: Statistical Physics in Biological Systems
BP 18.19: Poster
Mittwoch, 28. März 2012, 17:30–19:30, Poster A
Short Range Interaction Dynamics of Colloidal Particles in a Single Optical Potential — •Benjamin Tränkle and Alexander Rohrbach — Lab for Bio- and Nano-Photonics, University of Freiburg, Germany
In many biological systems, binding and unbinding events are of vital importance. Here, the accomplishment of initial contacts not only depend on a time independent association probability, but also on time dependent conformational changes of the interaction partners and therefore on a interaction duration τon. Furthermore, interaction dynamics are affected by long and short ranging forces, such as hydrodynamic, entropic and steric forces. Colloidal particles can serve as a model system for the investigation of such interaction events. We measure the 3D trajectories of two particles in a single potential, which is generated by an oscillating optical line trap. In this geometry, the reaction rate is increased due to the confined space, while rotational and translational degrees are preserved. With our setup, we can trap multiple beads and analyse particle motions at a spatial precision in the nanometer range and scanning frequencies up to 10 kHz. We show how various controls, i.e. the reaction volume or inter-particle potentials affect the interaction duration τon.