Protein Transport through a Narrow Solid-State Nanopore at High Voltage: Experiments and Theory
Protein Transport through a Narrow Solid-State Nanopore at High Voltage: Experiments and Theory
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DOI：
10.1021/nn301672g
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发表时间：
2012-07-01
期刊：
影响因子：
17.1
通讯作者：
Pelta, Juan
中科院分区：
文献类型：
--
作者：
Cressiot, Benjamin;Oukhaled, Abdelghani;Pelta, Juan
我们通过实验报道了未折叠蛋白质通过直径为3nm的狭窄固态纳米孔的传输作为施加电压的函数。随机线圈多肽链大于纳米孔。由于未展开链的限制，200 ~ 750mv电流阻塞的事件频率依赖关系遵循范霍夫-阿伦尼乌斯定律。在高压下，蛋白质在孔内呈延伸构象。我们观察到蛋白质的停留时间在中压下呈指数下降，在较高的电压下与电压成反比。这与易位机制一致，其中蛋白质被限制在孔中，产生熵障，随后是电泳运输。我们将这些结果与我们之前的研究结果进行了比较，其中有一个直径为20纳米的更大的孔。我们的数据表明，电渗透流动和蛋白质吸附在最窄的纳米孔壁上是最小的。我们讨论了得到的实验数据，并与最近的多电解质易位过程理论进行了比较。这个理论清楚地再现了中电压的熵势垒和高电压的电泳势垒之间的实验交叉。
We report experimentally the transport of an unfolded protein through a narrow solid-state nanopore of 3 nm diameter as a function of applied voltage. The random coil polypeptide chain is larger than the nanopore. The event frequency dependency of current blockades from 200 to 750 mV follows a van't Hoff-Arrhenius law due to the confinement of the unfolded chain. The protein is an extended conformation inside the pore at high voltage. We observe that the protein dwell time decreases exponentially at medium voltage and is inversely proportional to voltage for higher values. This is consistent with the translocation mechanism where the protein is confined in the pore, creating an entropic barrier, followed by electrophoretic transport. We compare these results to our previous work with a larger pore of 20 nm diameter. Our data suggest that electro-osmotic flow and protein adsorption on the narrowest nanopore wall are minimized. We discuss the experimental data obtained as compared with recent theory for the polyelectrolyte translocation process. This theory reproduces clearly the experimental crossover between the entropic barrier regime with medium voltage and the electrophoretic regime with higher voltage.