Cui S T
Department of Chemical Engineering, University of Tennessee, Knoxville, TN 37996-2200, USA.
Phys Rev Lett. 2007 Mar 30;98(13):138101. doi: 10.1103/PhysRevLett.98.138101. Epub 2007 Mar 26.
Molecular dynamics calculations are performed to investigate ionic current conduction through nanopores in the presence of single-stranded DNA. We find the counterions to be strongly attracted to the phosphate groups of the DNA, with resident time on the order of nanoseconds, while coions are strongly excluded. The diffusion constant of the counterions is calculated and used to estimate the ionic current through the pore, which gives a similar magnitude as in experiment. The results suggest a counterion-hopping mechanism along the ssDNA backbone in the current conduction through nanopores.
进行分子动力学计算以研究在单链DNA存在下通过纳米孔的离子电流传导。我们发现反离子被强烈吸引到DNA的磷酸基团上，驻留时间在纳秒量级，而共离子则被强烈排斥。计算了反离子的扩散常数，并用于估计通过孔的离子电流，其大小与实验结果相似。结果表明在通过纳米孔的电流传导中，沿着单链DNA主链存在反离子跳跃机制。
