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Current Fluctuations in Nanopores Reveal the Polymer-Wall Adsorption Potential
Physical Review Letters ( IF 8.1 ) Pub Date : 2021-09-23 , DOI: 10.1103/physrevlett.127.137801
Stuart F Knowles 1 , Nicole E Weckman 1 , Vincent J Y Lim 1 , Douwe J Bonthuis 2 , Ulrich F Keyser 1 , Alice L Thorneywork 1
Affiliation  

Modification of surface properties by polymer adsorption is a widely used technique to tune interactions in molecular experiments such as nanopore sensing. Here, we investigate how the ionic current noise through solid-state nanopores reflects the adsorption of short, neutral polymers to the pore surface. The power spectral density of the noise shows a characteristic change upon adsorption of polymer, the magnitude of which is strongly dependent on both polymer length and salt concentration. In particular, for short polymers at low salt concentrations no change is observed, despite the verification of comparable adsorption in these systems using quartz crystal microbalance measurements. We propose that the characteristic noise is generated by the movement of polymers on and off the surface and perform simulations to assess the feasibility of this model. Excellent agreement with experimental data is obtained using physically motivated simulation parameters, providing deep insight into the shape of the adsorption potential and underlying processes. This paves the way toward using noise spectral analysis for in situ characterization of functionalized nanopores.

中文翻译:

纳米孔中的电流波动揭示了聚合物壁的吸附潜力

通过聚合物吸附改变表面性质是一种广泛使用的技术,用于调节分子实验(如纳米孔传感)中的相互作用。在这里,我们研究了通过固态纳米孔的离子电流噪声如何反映短中性聚合物对孔表面的吸附。噪声的功率谱密度显示出聚合物吸附后的特征变化,其大小强烈依赖于聚合物长度和盐浓度。特别是,对于低盐浓度下的短聚合物,没有观察到变化,尽管使用石英晶体微量天平测量验证了这些系统中的可比吸附。我们建议特征噪声是由聚合物在表面上下移动产生的,并进行模拟以评估该模型的可行性。使用物理驱动的模拟参数获得了与实验数据的极好一致性,提供了对吸附势形状和潜在过程的深入了解。这为使用噪声频谱分析铺平了道路功能化纳米孔的原位表征。
更新日期:2021-09-23
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