Gutsche Christof, Kremer Friedrich, Krüger Matthias, Rauscher Markus, Weeber Rudolf, Harting Jens
Institut für Experimentalphysik I, Universität Leipzig, 04103 Leipzig, Germany.
J Chem Phys. 2008 Aug 28;129(8):084902. doi: 10.1063/1.2965127.
We present microrheological measurements of the drag force on colloids pulled through a solution of lambda-DNA (used here as a monodisperse model polymer) with an optical tweezer. The experiments show a drag force that is larger than expected from the Stokes formula and the independently measured viscosity of the DNA solution. We attribute this to the accumulation of DNA in front of the colloid and the reduced DNA density behind the colloid. This hypothesis is corroborated by a simple drift-diffusion model for the DNA molecules, which reproduces the experimental data surprisingly well, as well as by corresponding Brownian dynamics simulations.
我们展示了通过光学镊子对在λ-DNA溶液（在此用作单分散模型聚合物）中拉动的胶体上的阻力进行的微观流变学测量。实验表明，阻力大于斯托克斯公式和独立测量的DNA溶液粘度所预期的值。我们将此归因于胶体前方DNA的积累以及胶体后方DNA密度的降低。DNA分子的简单漂移扩散模型证实了这一假设，该模型惊人地重现了实验数据，相应的布朗动力学模拟也证实了这一点。
