纳柱阵列通道中生物分子等效淌度的宏观输运理论分析

各向异性生物分子或带电布朗粒子在周期性孔隙结构运动的分析在生物医学、水处理、环境工程等无数领域具有非常重要的意义. 本文基于宏观输运理论计算粒子在周期性微纳阵列结构中等效输运 参数, 预测分离结果. 首先通过引入构型熵及有效电荷等参数, 建立各向异性生物分子在纳米级受限环境下的等效布朗粒子模型, 然后应用宏观输运理论和数值方法计算分子的等效淌度. 以小分子DNA 片段在周期性纳柱阵列通道中电泳迁移为例, 证明当通道空隙接近或小于分子尺寸时, 熵受限对分子的等效迁移速度有重要的影响, 是实现生物分子分离的主要机理. 因为熵受限的作用随着外电场的增强而减低,所以在较低电场强度条件下, 分子淌度差别较大, 对应分离效果较佳. 关键词： 生物分子分离 构型熵 微纳阵列 宏观输运理论

Macrotransport analysis of effective mobility of biomolecules in periodic nano-filter polar arrays

Transport of anisotropic biomolecules and/or charged Brownian particles in periodic porous media is of great importance in the fields of biomedicine, water treatment, and environmental engineering etc. In this paper, we present the modeling of transport of biomolecules in periodic polar arrays based on a numerical analysis of effective mobility. Anisotropic biomolecules are transformed to point-sized Brownian particles through introduction of configurational entropy, and the effective charge and effective transport parameters are calculated using macrotransport theory. As an example, the mobility of short dsDNA fragments in a nano-polar array is calculated. It is demonstrated that when the sizes of the gaps between the nano-poles are similar to or smaller than the size of biomolecules, the configurational entropy has a significant effect on the effective velocity. Difference in configurational entropy in the confined space dominates the partitioning of the molecules. In addition, as the effect of entropic barrier decreases with the strength of external electric field, relatively low voltage is preferred in order to achieve better selectivity.
Keywords： biomolecular separation configurational entropy nanofilter array macrotransport