Single ion-channel recordings using glass nanopore membranes

Ryan J. White, Eric N. Ervin, Tinglu Yang, Xin Chen, Susan Daniel, Paul S. Cremer, Henry S. White

Research output: Contribution to journalArticle

206 Scopus citations

Abstract

Protein ion-channel recordings using a glass nanopore (GNP) membrane as the support structure for lipid bilayer membranes are presented. The GNP membrane is composed of a single conical-shaped nanopore embedded in a ∼50 μm-thick glass membrane chemically modified with a 3- cyanopropyldimethylchlorosilane monolayer to produce a surface of intermediate hydrophobicity. This surface modification results in lipid monolayer formation on the glass surface and a lipid bilayer suspended across the small orifice (100-400 nm-radius) of the GNP membrane, while allowing aqueous solutions to fully wet the glass nanopore. The GNP membrane/bilayer structures, which exhibit ohmic seal resistances of ∼70 GΩ and electrical breakdown voltages of ∼0.8 V, are exceptionally stable to mechanical disturbances and have lifetimes of at least 2 weeks. These favorable characteristics result from the very small area of bilayer (10-10-10-8 cm2) that is suspended across the GNP membrane orifice. Fluorescence microscopy and vibrational sum frequency spectroscopy demonstrate that a lipid monolayer forms on the 3-cyanopropyl-dimethylchlorosilane modified glass surface with the lipid tails oriented toward the glass. The GNP membrane/bilayer structure is well suited for single ion-channel recordings. Reproducible insertion of the protein ion channel, wild-type α-hemolysin (WTαHL), and stochastic detection of a small molecule, heptakis-(6-O-sulfo)-β-cyclodextrin, are demonstrated. In addition, the insertion and removal of WTαHL channels are reproducibly controlled by applying small pressures (-100 to 350 mmHg) across the lipid bilayer. The electrical and mechanical stability of the bilayer, the ease of which bilayer formation is achieved, and the ability to control ion-channel insertion, coupled with the small bilayer capacitance of the GNP membrane-based system, provide a new and nearly optimal system for single ion-channel recordings.

Original languageEnglish (US)
Pages (from-to)11766-11775
Number of pages10
JournalJournal of the American Chemical Society
Volume129
Issue number38
DOIs
StatePublished - Sep 26 2007

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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