Membrane patches as ion channel probes for scanning ion conductance microscopy

Wenqing Shi, Yuhan Zeng, Lushan Zhou, Yucheng Xiao, Theodore Cummins, Lane A. Baker

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We describe dual-barrel ion channel probes (ICPs), which consist of an open barrel and a barrel with a membrane patch directly excised from a donor cell. When incorporated with scanning ion conductance microscopy (SICM), the open barrel (SICM barrel) serves to measure the distance-dependent ion current for non-invasive imaging and positioning of the probe in the same fashion of traditional SICM. The second barrel with the membrane patch supports ion channels of interest and was used to investigate ion channel activities. To demonstrate robust probe control with the dual-barrel ICP-SICM probe and verify that the two barrels are independently addressable, current-distance characteristics (approach curves) were obtained with the SICM barrel and simultaneous, current-time (I-T) traces were recorded with the ICP barrel. To study the influence that the distance between ligand-gated ion channels (i.e., large conductance Ca2+-activated K+ channels/BK channels) and the ligand source (i.e., Ca2+ source) has on channel activations, ion channel activities were recorded at two fixed probe-substrate distances (Dps) with the ICP barrel. The two fixed positions were determined from approach curves acquired with the SICM barrel. One position was defined as the “In-control” position, where the probe was in close proximity to the ligand source; the second position was defined as the “Far” position, where the probe was retracted far away from the ligand source. Our results confirm that channel activities increased dramatically with respect to both open channel probability and single channel current when the probe was near the ligand source, as opposed to when the probe was far away from the ligand source.

Original languageEnglish (US)
Pages (from-to)81-97
Number of pages17
JournalFaraday Discussions
Volume193
DOIs
StatePublished - 2016

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Ion Channels
Microscopy
Microscopic examination
Ions
membranes
microscopy
Membranes
Scanning
scanning
probes
Ligands
ions
ligands
Large-Conductance Calcium-Activated Potassium Channels
Ligand-Gated Ion Channels
Calcium-Activated Potassium Channels
Position control
curves
ion currents
positioning

ASJC Scopus subject areas

  • Medicine(all)
  • Physical and Theoretical Chemistry

Cite this

Membrane patches as ion channel probes for scanning ion conductance microscopy. / Shi, Wenqing; Zeng, Yuhan; Zhou, Lushan; Xiao, Yucheng; Cummins, Theodore; Baker, Lane A.

In: Faraday Discussions, Vol. 193, 2016, p. 81-97.

Research output: Contribution to journalArticle

Shi, Wenqing ; Zeng, Yuhan ; Zhou, Lushan ; Xiao, Yucheng ; Cummins, Theodore ; Baker, Lane A. / Membrane patches as ion channel probes for scanning ion conductance microscopy. In: Faraday Discussions. 2016 ; Vol. 193. pp. 81-97.
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