Transport at the nanoscale: temperature dependence of ion conductance
Transport at the nanoscale: temperature dependence of ion conductance
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DOI：
10.1007/s00249-008-0366-0
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发表时间：
2008-11-01
影响因子：
2
通讯作者：
Kleinekathoefer, Ulrich
中科院分区：
文献类型：
--
作者：
Chimerel, Catalin;Movileanu, Liviu;Kleinekathoefer, Ulrich
在较宽的电解液浓度范围内测量了纳米孔中随温度变化的离子电导，并与分子模拟结果进行了比较。将来自大肠杆菌的单个外膜蛋白F(OmpF)通道重组为平面脂双层。与实验数据定性一致的是，外场分子动力学揭示了离子输运的原子细节。在0~90℃温度范围内，比较通道电导和体电导率随温度的变化关系，发现在低盐浓度时，输运主要是沿孔表面进行的。随着盐浓度的增加，表面电荷输运饱和，纳米孔中心离子输运。纳米孔的限制有利于离子对的形成。温度的升高缩短了离子对的寿命，增加了沟道电导，增加的程度超过了体相行为的预期。
Temperature dependent ion conductance in nanopores is measured in a wide range of electrolyte concentrations and compared with molecular modeling. Single outer membrane protein F (OmpF) channels from E. coli are reconstituted into planar lipid bilayers. In qualitative agreement with the experimental data, applied-field molecular dynamics unraveled atomistic details of the ion transport. Comparing the temperature dependence of the channel conductance with that of the bulk conductivity in the range from 0 to 90 degrees C revealed that at low salt concentrations the transport is mainly driven along the pore surface. Increasing the salt concentration saturates the surface charge transport and induces ion transport in the center of the nanopore. The confinement of the nanopore then favors the formation of ion pairs. Stepping up the temperature reduces the life time of the ion pairs and increases the channel conductance more than expected from the bulk behavior.