Wu Linsong, Wu Fengmin, Kou Jianlong, Lu Hangjun, Liu Yang
Department of Physics, Zhejiang Normal University, Jinhua, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Jun;83(6 Pt 1):061913. doi: 10.1103/PhysRevE.83.061913. Epub 2011 Jun 16.
The transportation of water across a cell membrane facilitated by water channel proteins is fundamental to the normal water metabolism in all forms of life. It is understood that the narrow region in a water channel is responsible for gating or selectivity. However, the influence of the position of the narrow region on water transportation is still not thoroughly understood. By choosing a single-walled carbon nanotube (SWNT) as a simplified model and using molecular dynamics simulation, we have found that the water flux through the nanotube would change significantly if the narrow location moves away from the middle region along the tube. Simulation results show that the flux reaches the maximum when the deformation occurs in the middle part of nanotube and decreases as the deformation location moves toward the ends of the nanotube. However, the decrease of water flux is not monotonic and the flux gets the minimum near the ends. These interesting phenomena can be explained in terms of water-water interactions and water-SWNT interactions. It can be concluded that the regulation of water transportation through nanopores depends sensitively on the location of the narrow region, and these findings are helpful in devising high flux nanochannels and nanofiltration as well.
水通道蛋白促进水跨细胞膜的运输对于所有生命形式的正常水代谢至关重要。据了解，水通道中的狭窄区域负责门控或选择性。然而，狭窄区域位置对水运输的影响仍未被完全理解。通过选择单壁碳纳米管（SWNT）作为简化模型并使用分子动力学模拟，我们发现如果狭窄位置沿管从中部移开，通过纳米管的水通量将发生显著变化。模拟结果表明，当纳米管中部发生变形时通量达到最大值，并且随着变形位置向纳米管两端移动而减小。然而，水通量的减小不是单调的，并且在两端附近通量最小。这些有趣的现象可以用水 - 水相互作用和水 - SWNT相互作用来解释。可以得出结论，通过纳米孔的水运输调节敏感地取决于狭窄区域的位置，并且这些发现也有助于设计高通量纳米通道和纳滤。
