Effect of salt gradients on DNA translocation through solid-state nanopores

盐浓度梯度对DNA通过固态纳米孔的影响（英文）

Aiming at the issues of controlling the translocation speed of DNA through a solid-state nanopore and enlarging the signal-to-noise ratio of ionic current modulation, which are challenges for the application of nanopore technology in DNA detection, salt concentration gradients are applied across the nanopore to investigate their influence on the DNA translocation time and signal-to-noise ratio. Experimental data demonstrates that, in symmetric concentration conditions, both the current blockade and dwell time for A-DNA translocation through a solid-state nanopore increase along with potassium chloride concentration. When the concentration in the trans chamber is decreased from 1 to 0.1 mol/L, keeping the concentration of the cis chamber at 1 mol/L, the normalized current blockade is found to be increased by one order. The increased dwell time and enhanced signal-to-noise ratio are achieved with salt gradients across the nanopore, which can improve the sensitivity when detecting DNA samples.

针对DNA过孔速度过快以及信噪比低等制约固态纳米孔应用于DNA分子检测的问题,通过改变纳米孔两侧盐溶液的浓度,研究了其对DNA的过孔时间以及信噪比的影响.实验结果表明,当纳米孔两侧氯化钾溶液浓度相同时,λ-DNA的过孔时间以及电流堵塞信号都随着氯化钾浓度的提高而增加.但当纳米孔cis端的KCL浓度保持在1 mol/L,trans端的氯化钾浓度由1 mol/L变为0.1 mol/L时,归一化后的电流信号幅值增加了1个数量级.因此,调整纳米孔两端盐溶液的浓度梯度可以有效降低DNA的过孔速度和提高信噪比,从而大大提高了纳米孔在DNA分子检测方面的灵敏度.