Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556-5637, USA.
Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556-5637, USA.
J Chem Phys. 2020 Jul 21;153(3):035102. doi: 10.1063/5.0013195.
We report the first analytical theory on the amplitude of resistive signals during molecular translocation through charged solid-state nanopores with variable cross-sectional area and piecewise-constant surface charge densities. By providing closed-form explicit algebraic expressions for the concentration profiles inside charged nanopores, this theory allows the prediction of baseline and translocation resistive signals without the need for numerical simulation of the electrokinetic phenomena. A transversely homogenized theory and an asymptotic expansion for weakly charged pores capture DC or quasi-static rectification due to field-induced intrapore concentration polarization (as a result of pore charge inhomogeneity or a translocating molecule). This theory, validated by simulations and experiments, is then used to explain why the amplitude of a single stranded DNA molecule can be twice as high as the amplitude of its double stranded counterpart. It also suggests designs for intrapore concentration polarization and volume exclusion effects that can produce biphasic and other amplitude fingerprints for high-throughput and yet discriminating molecular identification.
我们报告了第一个关于在带有可变横截面和分段恒定表面电荷密度的带电固态纳米孔中分子通过时电阻信号幅度的分析理论。通过为带电纳米孔内的浓度分布提供封闭形式的显式代数表达式，该理论允许在无需对电动现象进行数值模拟的情况下预测基线和迁移电阻信号。一个横向均匀化理论和一个弱带电孔的渐近展开式可以捕获由于场诱导孔内浓度极化（由于孔电荷不均匀或迁移分子）引起的直流或准静态整流。该理论通过模拟和实验得到了验证，然后用于解释为什么单链 DNA 分子的幅度可以是双链 DNA 分子幅度的两倍。它还为孔内浓度极化和体积排除效应的设计提供了依据，这些设计可以产生双峰和其他幅度指纹，用于高通量和有区别的分子识别。
