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Updated: Aug 10, 2026

Fine-tuning the Size and Minimizing the Noise of Solid-state Nanopores
Published on: October 31, 2013
Negative incremental resistance induced by calcium in asymmetric nanopores
Zuzanna S Siwy1, Matthew R Powell, Eric Kalman
1Department of Physics and Astronomy, University of California, Irvine, 92697, USA. zsiwy@uci.edu
Abstract:
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 approximately 1 mum. 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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