Article

Probing the Transport of Ionic Liquids in Aqueous Solution through Nanopores

Journal of Physical Chemistry Letters (Impact Factor: 7.46). 08/2011; 2(18):2331-2336. DOI: 10.1016/j.bpj.2011.11.1118

ABSTRACT

The temperature-dependent transport of the ionic liquid 1-butyl-3-methyl-imidazolium chloride (BMIM-Cl) in aqueous solution is studied theoretically and experimentally. Using molecular dynamics simulations and ion-conductance measurements, the transport is examined in bulk as well as through a biological nanopore, that is, OmpF and its mutant D113A. This investigation is motivated by the observation that aqueous solutions of BMIM-Cl drastically reduce the translocation speed of DNA or antibiotics through nanopores in electrophysiological measurements. This makes BMIM-Cl an interesting alternative salt to improve the time resolution. In line with previous investigations of simple salts, the size of the ions and their orientation adds another important degree of freedom to the ion transport, thereby slowing the transport through nanopores. An excellent agreement between theory and conductance measurements is obtained for wild type OmpF and a reasonable agreement for the mutant. Moreover, all-atom simulations allow an atomistic analysis revealing molecular details of the rate-limiting ion interactions with the channel.

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Available from: Mathias Winterhalter, Sep 17, 2015
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    • "These values reflect the stronger interaction inside the channel. Free diffusion of KCl in water gives about 6 kT, whereas the barrier for KCl inside OmpF is slightly higher (8 kT), reflecting the enhanced interaction inside the channel (Modi et al. 2011). Experimentally the ion conductance is an averaged property over the entire channel. "
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    Full-text · Dataset · Nov 2015
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    • "These values reflect the stronger interaction inside the channel. Free diffusion of KCl in water gives about 6 kT, whereas the barrier for KCl inside OmpF is slightly higher (8 kT), reflecting the enhanced interaction inside the channel (Modi et al. 2011). Experimentally the ion conductance is an averaged property over the entire channel. "
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