中国物理B ›› 2012, Vol. 21 ›› Issue (7): 76102-076102.doi: 10.1088/1674-1056/21/7/076102

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Using a water-confined carbon nanotube to probe electricity of sequential charged segments of macromolecules

王禹a, 赵艳皎b, 黄吉平a   

  1. a Department of Physics and State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China;
    b Advanced Materials Laboratory, Fudan University, Shanghai 200438, China
  • 收稿日期:2012-03-16 出版日期:2012-06-01 发布日期:2012-06-01
  • 基金资助:
    Project supported by the Fok Ying Tung Education Foundation, China (Grant No. 131008), the National Basic Research Program of China (Grant No. 2011CB922004), and the National Natural Science Foundation of China (Grant No. 11075035).

Using a water-confined carbon nanotube to probe electricity of sequential charged segments of macromolecules

Wang Yu(王禹)a), Zhao Yan-Jiao(赵艳皎)b), and Huang Ji-Ping(黄吉平)a)†   

  1. a Department of Physics and State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China;
    b Advanced Materials Laboratory, Fudan University, Shanghai 200438, China
  • Received:2012-03-16 Online:2012-06-01 Published:2012-06-01
  • Contact: Huang Ji-Ping E-mail:jphuang@fudan.edu.cn
  • Supported by:
    Project supported by the Fok Ying Tung Education Foundation, China (Grant No. 131008), the National Basic Research Program of China (Grant No. 2011CB922004), and the National Natural Science Foundation of China (Grant No. 11075035).

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摘要： The detection of macromolecular conformation is particularly important in many physical and biological applications. Here we theoretically explore a method for achieving this detection by probing the electricity of sequential charged segments of macromolecules. Our analysis is based on molecular dynamics simulations, and we investigate a single file of water molecules confined in a half-capped single-walled carbon nanotube (SWCNT) with an external electric charge of +e or ?e (e is the elementary charge). The charge is located in the vicinity of the cap of the SWCNT and along the centerline of the SWCNT. We reveal the picosecond timescale for the re-orientation (namely, from one unidirectional direction to the other) of the water molecules in response to a switch in the charge signal, ?e → +e or +e → ?e. Our results are well understood by taking into account the electrical interactions between the water molecules and between the water molecules and the external charge. Because such signals of re-orientations can be magnified and transported according to Tu et al. [2009 Proc. Natl. Acad. Sci. USA 106 18120], it becomes possible to record fingerprints of electric signals arising from sequential charged segments of a macromolecule, which are expected to be useful for recognizing the conformations of some particular macromolecules.

关键词: molecular dynamics simulation, macromolecular conformation, single-walled carbon nanotube, water molecule

Abstract: The detection of macromolecular conformation is particularly important in many physical and biological applications. Here we theoretically explore a method for achieving this detection by probing the electricity of sequential charged segments of macromolecules. Our analysis is based on molecular dynamics simulations, and we investigate a single file of water molecules confined in a half-capped single-walled carbon nanotube (SWCNT) with an external electric charge of +e or ?e (e is the elementary charge). The charge is located in the vicinity of the cap of the SWCNT and along the centerline of the SWCNT. We reveal the picosecond timescale for the re-orientation (namely, from one unidirectional direction to the other) of the water molecules in response to a switch in the charge signal, ?e → +e or +e → ?e. Our results are well understood by taking into account the electrical interactions between the water molecules and between the water molecules and the external charge. Because such signals of re-orientations can be magnified and transported according to Tu et al. [2009 Proc. Natl. Acad. Sci. USA 106 18120], it becomes possible to record fingerprints of electric signals arising from sequential charged segments of a macromolecule, which are expected to be useful for recognizing the conformations of some particular macromolecules.

Key words: molecular dynamics simulation, macromolecular conformation, single-walled carbon nanotube, water molecule

中图分类号:  (Computer simulation of liquid structure)

  • 61.20.Ja
61.25.H- (Macromolecular and polymers solutions; polymer melts)