Viscosity of aqueous DNA solutions determined using dynamic light scattering
Viscosity of aqueous DNA solutions determined using dynamic light scattering
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DOI：
10.1039/c1an15475c
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发表时间：
2011-01-01
期刊：
影响因子：
4.2
通讯作者：
Rodger, Alison
中科院分区：
文献类型：
--
作者：
Gilroy, Emma L.;Hicks, Matthew R.;Rodger, Alison
粘度是表征液体行为及其流动的关键参数。然而，很难在微升体积尺度上精确地、可再现地和准确地测量水溶液，而这通常是生物样品所需要的。我们报告了一种新的方法来测量动态粘度的发展，通过测量动态光散射（DLS）的数据范围内的颗粒的定义明确的大小。DLS的大多数应用涉及确定已知粘度的样品的粒度。我们颠倒了通常的协议，并努力确定已知粒度的样品的粘度。用动态光散射法测定了小牛胸腺DNA水溶液和水溶液的粘度，并与U型管粘度计测定的结果进行了比较。苯乙烯颗粒，经常被用作粒度标准，给我们的DNA样品的C-6衍生的二氧化硅和带正电荷的氨基聚苯乙烯微球的结果不令人满意。然而，带负电荷的羧酸盐聚苯乙烯微球颗粒容易在温度范围（0-100 ° C）内给出准确的粘度测量。所需的样品体积取决于用于测量DLS的比色皿，但可以使用40至3000 μ L的样品量进行测量。然后可以回收样品用于后续实验。DLS方法在不同温度下执行起来很简单，并且提供的数据准确度远高于U型管粘度计。我们的研究结果还表明了一种前进的方式，以准确地说明在DLS的粒度测定的正常应用中的溶液粘度，包括适当的非相互作用的颗粒作为内标。
Viscosity is a key parameter for characterising the behaviour of liquids and their flow. It is, however, difficult to measure precisely, reproducibly and accurately for aqueous solutions on a micro-litre volume scale, which is what is usually needed for biological samples. We report the development of a new method for measuring dynamic viscosity by measuring dynamic light scattering (DLS) data for a range of particles of well-defined size. Most applications of DLS involve determining particle size for samples of known viscosity. We inverted the usual protocol and endeavoured to determine viscosity for samples of known particle size. Viscosity measurements for water and aqueous solutions of calf thymus DNA made using DLS were compared with those from a U-tube viscometer. The styrene particles, frequently used as particle size standards, gave unsatisfactory results for our DNA samples as did C-6 derivatized silica and positively charged amino polystyrene microspheres. However, negatively charged carboxylate polystyrene microspheres particles readily gave accurate viscosity measurements over a range of temperatures (0-100 degrees C). The sample volume required depends on the cuvette used to measure DLS, but can be performed with samples sizes ranging from 40 to 3000 mu L. The sample can then be recovered for subsequent experiments. The DLS method is simple to perform at different temperatures and provides data of accuracy significantly above that of a U-tube viscometer. Our results also indicate a way forward to account accurately for solution viscosity in the normal applications of DLS to particle size determination by including the appropriate non-interacting particles as an internal standard.