Department of Physics, Systems Biophysics, Center for Nanoscience, Ludwig Maximilians Universität München, München, Germany.
Electrophoresis. 2010 Jan;31(2):279-86. doi: 10.1002/elps.200900505.
The manipulation and analysis of biomolecules in native bulk solution is highly desired; however, few methods are available. In thermophoresis, the thermal analog to electrophoresis, molecules are moved along a microscopic temperature gradient. Its theoretical foundation is still under debate, but practical applications for analytics in biology show considerable potential. Here we measured the thermophoresis of highly diluted single stranded DNA using an all-optical capillary approach. Temperature gradients were created locally by an infrared laser. The thermal depletion of oligonucleotides of between 5 and 50 bases in length were investigated by fluorescence at various salt concentrations. To a good approximation, the previously tested capacitor model describes thermophoresis: the Soret coefficient linearly depends on the Debye length and is proportional to the DNA length to the power of 0.35, dictated by the conformation-based size scaling of the diffusion coefficient. The results form the basis for quantitative DNA analytics using thermophoresis.
在原生体溶液中对生物分子进行操作和分析是人们非常期望的，但目前可用的方法却很少。在热泳中，分子沿着微观温度梯度移动，这是电泳的热模拟。其理论基础仍存在争议，但在生物学分析中的实际应用显示出了相当大的潜力。在这里，我们使用全光学毛细管方法测量了高度稀释的单链 DNA 的热泳。通过红外激光在局部产生温度梯度。通过在不同盐浓度下的荧光研究了长度在 5 到 50 个碱基之间的寡核苷酸的热耗散。以前经过测试的电容器模型很好地描述了热泳：Soret 系数与德拜长度线性相关，并且与 DNA 长度的 0.35 次方成正比，这是由扩散系数基于构象的尺寸缩放决定的。这些结果为使用热泳进行定量 DNA 分析奠定了基础。
