来自中科院上海应用物理所,浙江大学物理学系,上海交通大学生命科学与技术学院的研究人员运用分子动力学模拟方法,利用仿生的思想,参考生物水通道中分布在重要氨基酸残基上的电荷分布,利用特定半径的纳米碳管,设计出使管内水分子定向运动的纳米尺度水泵,并阐明了相关的物理机理。研究结果发表在国际权威科学期刊Nature子期刊——《自然—纳米技术》(Nature Nanotechnology)10月21日的提前网上版上,《自然—纳米技术》同时刊发专题评论文章指出:“……他们的计算结果预言了有一种最佳的电荷排列方式会使得水被泵向所需的方向,……该研究成果对于设计用于污水处理、海水净化以及生物芯片上的高效纳米水泵具有一定的启示性。”
文章的通讯作者是中科院上海应用物理所的方海平研究员,以及上海交通大学的生物医学工程专家胡钧,后者为上海交大的长江学者,特聘教授。
分子机器是人类的一个梦想,是纳米科学技术的一个终极目标。虽然,初步的实验已经构建了一些简单的人工分子器件,如小的有机分子棘轮、纳米车轮等,但是由于目前技术水平的限制,很难做出像生物分子机器那样精细复杂的结构并实现其高级功能。近年来,借鉴生物系统中已有的一些本质的东西来设计具有类似特性的人工分子机器的思路逐渐获得人们的重视。这个纳米水泵的设计正是这个思路的一个体现。
这一工作的一个核心是限制于这种纳米水通道中的水表现出沿着纳米水通道轴向的准一维水链,并在通道内形成准一维氢键网络的特性。在他们的前期工作中已经揭示出,这样的准一维水链表现出优异的力学和电学开关特性(JACS. 127, 7166-7170;Proc. Natl. Acad. Sci. USA. 104,3687-3692)。在参考生物水通道中的电荷分布引起的非对称电场作用下,这样的准一维水链在保持特定的氢键方向的同时,又维持相对低的通透阻尼,使水分子定向地从纳米管道的一端流向另一端。
原始出处:
Nature Nanotechnology 2, 709 - 712 (2007)
Published online: 21 October 2007 | doi:10.1038/nnano.2007.320
Subject Categories: Nanofluidics | Computational nanotechnology
A charge-driven Lu1,2,4, Rongzheng Wan1, Jichen Li5, Jun Hu1,6 & Haiping Fang1
Abstract
Understanding and controlling the transport of water across nanochannels is of great importance for designing novel molecular devices, machines and sensors and has wide applications1, 2, 3, 4, 5, 6, 7, 8, 9, including the desalination of seawater5. Nanopumps driven by electric or magnetic fields can transport ions10, 11 and magnetic quanta12, but water is charge-neutral and has no magnetic moment. On the basis of molecular dynamics simulations, we propose a design for a molecular water pump. The design uses a combination of charges positioned adjacent to a nanopore and is inspired by the structure of channels in the cellular membrane that conduct water in and out of the cell (aquaporins). The remarkable pumping ability is attributed to the charge dipole-induced ordering of water confined in the nanochannels13, 14, where water can be easily driven by external fields in a concerted fashion. These findings may provide possibilities for developing water transport devices that function without osmotic pressure or a hydrostatic pressure gradient.
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, PO Box 800-204, Shanghai 201800, China
Graduate School of the Chinese Academy of Sciences, Beijing 100080, China
Department of Physics, Zhejiang University, Hangzhou, 310027, China
Department of Physics, Zhejiang Normal University, 321004, Jinhua, China
Department of Physics and Astronomy, The University of Manchester, Manchester M60 1QD, UK
Bio-X Life Sciences Research Center, College of Life Science and Technology, Shanghai JiaoTong University, Shanghai 200030, China
Correspondence to: Jun Hu1,6 e-mail: jhu@sjtu.edu.cn
Correspondence to: Haiping Fang1 e-mail: fanghaiping@sinap.ac.cn