Berlin 2005 – scientific programme
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AKB: Biologische Physik
AKB 100: Poster Session I
AKB 100.63: Poster
Saturday, March 5, 2005, 16:45–18:45, Poster TU D
Domain Size Influences the Diffusive Behavior of Nano-Particles in Langmuir Monolayers — •Florian Rückerl1, Douglas Martin2, Martin Forstner3, and Carsten Selle1 — 1Universität Leipzig, Inst. Exp. Physik I, PWM, Linnéstr. 5, 04103 Leipzig — 2Brandeis University — 3UC Berkeley
We modelled protein diffusion in inhomogeneous cell membranes utilizing lipid monolayers at the air/water interface where liquid-condensed (LC) domains coexist in a liquid-expanded (LE) phase. The motion of negatively charged fluorescent latex beads as model proteins within LE phase was monitored by Single-Particle-Tracking. The diffusion of those particles was apparently affected by dipole-dipole interactions leading to observation of domain-associated movement. We calculated the shape of the electric field of the condensed domains dependent on the distance r to the domain (rbead< r < 20 µ m). On altering the domain sizes, the resulting potential changes from U∝1/|r|3 for a single dipole to U∝1/|r| for large domain radii (R>10µ m). This is a significant change from a short to a long ranged potential.
Monte Carlo simulations support the influence of the interactions on model protein diffusion. Furthermore, the diffusion is affected by the potential depth and shape, leading to anomalous diffusion on different time scales, corresponding to the time needed for the model protein to cover the area of the size of the domain.