Duhr Stefan, Braun Dieter
Biophysics, Ludwig Maximilians Universität München, Amalienstrasse 54, 80799 München, Germany.
Phys Rev Lett. 2006 Jul 21;97(3):038103. doi: 10.1103/PhysRevLett.97.038103.
Thermophoresis moves molecules along temperature gradients, typically from hot to cold. We superpose fluid flow with thermophoretic molecule flow under well-defined microfluidic conditions, imaged by fluorescence microscopy. DNA is trapped and accumulated 16-fold in regions where both flows oppose each other. Strong 800-fold accumulation is expected, however, with slow trapping kinetics. The experiment is equally described by a three-dimensional and one-dimensional analytical model. As an application, we show how a radially converging temperature field confines short DNA into a 10 microm small spot.
热泳作用使分子沿着温度梯度移动，通常是从热端移向冷端。在明确的微流体条件下，我们将流体流动与热泳分子流叠加，并通过荧光显微镜成像。在两种流动方向相反的区域，DNA被困住并积累了16倍。然而，由于捕获动力学缓慢，预计会有800倍的强烈积累。该实验同样可以用三维和一维分析模型来描述。作为一个应用实例，我们展示了径向收敛的温度场如何将短DNA限制在一个10微米的小点内。
