Regensburg 2010 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 31: Posters: Membranes and Vesicles
BP 31.12: Poster
Donnerstag, 25. März 2010, 17:15–20:00, Poster B1
Hydrodynamic interaction of particles in scanning line optical tweezers — •Benjamin Tränkle1, Michael Speidel2, and Alexander Rohrbach1 — 1Lab for Bio- and Nano-Photonics, University of Freiburg, Germany — 2Sick-Stegmann, Donaueschingen, Germany
In living cells, the distance of reaction partners determines whether biological processes take place or not. This is especially the case for the fusion of vesicles. Physical interactions within the cell, i.e. hydrodynamic and entropic forces play a crucial role in this context since the motion of vesicles is confined by the size of compartments inherent to the cell structure. Therefore, we are studying the dynamic interaction of at least 2 particles diffusing within a confined volume by using an optical trapping potential. This model system allows the particles to get in close contact to one another due to Brownian position fluctuations. The system is realized by an oscillating optical trap, with a scanning frequency up to 5 kHz and a lateral extension of about 10µm. The laser power is modulated while scanning. Thereby an elongated optical potential is generated. Artificially created volumes can simulate the cell compartments and the confined motion of particles within these bounding walls is expected to be influenced due to interaction potentials. By scanning the particles, their 3D position is obtained by back focal plane interferometry and recorded with up to 10 kHz. The particle trajectories can now be used to calculate the interaction potential and hydrodynamic coupling.