LAMBE UMR CNRS 8587, Evry and Cergy-Pontoise University, France.
J Phys Chem B. 2011 Mar 31;115(12):2890-8. doi: 10.1021/jp200326w. Epub 2011 Mar 10.
We use solid-state nanopores to study the dynamics of single electrically charged colloids through nanopores as a function of applied voltage. We show that the presence of a single colloid inside of the pore changes the pore resistance, in agreement with theory. The normalized ionic current blockade increases with the applied voltage and remains constant when the electrical force increases even more. We observe short and long events of current blockades. Their durations are associated, respectively, with low and high current variation. The ratio of long events increases with the electrical force. The events frequency increases exponentially as a function of applied voltage and saturates at high voltage. The dwelling time decreases exponentially at low and medium voltages when the electrical force increases. At large voltages, this time decreases inversely proportionally to the applied voltage. The long events are associated with translocation events. We show that the dynamics of colloids through the nanopore is governed mainly by two mechanisms, by the free-energy barrier at relatively low and medium voltages and by the electrophoresis mechanism at high voltage.
我们使用固态纳米孔研究单个带电胶体在纳米孔中的动力学，作为外加电压的函数。我们表明，单个胶体在孔内的存在会改变孔电阻，这与理论相符。归一化离子电流阻塞随着外加电压的增加而增加，并且当电场力增加更多时保持不变。我们观察到电流阻塞的短时间和长时间事件。它们的持续时间分别与低电流变化和高电流变化相关。长事件的比例随着电场力的增加而增加。事件频率随外加电压呈指数增加，并在高电压下饱和。当外加电场力增加时，低中和中电压下的停留时间呈指数下降。在高电压下，这段时间与外加电压成反比。长事件与转位事件有关。我们表明，胶体在纳米孔中的动力学主要由两个机制控制，即在相对低中和中电压下由自由能势垒控制，在高电压下由电泳机制控制。
