title: Negative incremental resistance induced by calcium in asymmetric nanopores.
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.
authors.affiliation: Department of Physics and Astronomy, University of California, Irvine, 92697, USA. zsiwy@uci.edu
authors.forename: Zuzanna S
authors.initials: ZS
authors.lastname: Siwy
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Powell
authors.forename: Eric
authors.initials: E
authors.lastname: Kalman
authors.forename: R Dean
authors.initials: RD
authors.lastname: Astumian
authors.forename: Robert S
authors.initials: RS
authors.lastname: Eisenberg
mesh_terms: D002118:Calcium / Q000737:chemistry / Q000494:pharmacology*; D002413:Cations, Divalent / Q000737:chemistry; D008954:Models, Biological; D049329:Nanostructures / Q000737:chemistry*
chemical_list: D002413:Cations, Divalent; D002118:Calcium