Negative Incremental Resistance Induced by Calcium in Asymmetric Nanopores

Zuzanna S. Siwy,*† Matthew R. Powell,† Eric Kalman,† R. Dean Astumian,‡ and Robert S. Eisenberg§
University of California, Irvine, Department of Physics and Astronomy, Irvine, California 92697, University of Maine, Department of Physics, Orono, Maine 04469, and Rush Medical College, Department of Molecular Biophysics & Physiology, Chicago, Illinois 60612
Nano Lett., 2006, 6 (3), pp 473–477
DOI: 10.1021/nl0524290
Publication Date (Web): February 2, 2006
Copyright © 2006 American Chemical Society
*

 Corresponding author. E-mail:  zsiwy@uci.edu.

,
†

 University of California, Irvine.

,
‡

 University of Maine.

,
§

 Rush Medical College.

Abstract

Abstract Image

Single polymer nanopores with permanent surface charges act as rectifiers of ionic current. The pores are tapered cones with narrow openings of several nanometers and wide openings of 1 μm. The pores are cation-selective, and in symmetric solutions of potassium chloride they rectify the flow of potassium ions from the small opening toward the wide opening. Millimolar concentrations of calcium reverse the rectification, and a negative incremental resistance is observed. These observations can be interpreted by a model containing flashing ratchets.

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History

  • Published In Issue March 08, 2006
  • Received December 8, 2005
    Revised Manuscript Received January 23, 2006

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