Single Cell Titration-Type Assay for Plasma Membrane Cholesterol Chemical Potential

Meiling Zhang, Linyu Li, Danjun Fang, Thomas J. Kelley, James D. Burgess

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

In this paper, a titration-type assay is described that determines the minimum concentration of cholesterol in solution that is required to drive net influx of cholesterol to the plasma membrane and thus increase the cholesterol concentration. The increase in cholesterol in the plasma membrane is detected by cholesterol diffusion at the site of contact by a cholesterol oxidase-modified microelectrode. In the presented thermodynamic model, the minimum solution phase cholesterol concentration that drives influx to the plasma membrane is a close approximation of the true solution-phase equilibrium concentration of cholesterol produced from cellular cholesterol efflux and as such it is a quantitative measure of the chemical potential of cholesterol in the cellular plasma membrane. This assay provides a measure of cholesterol chemical potential in the living cellular plasma membrane through reference to a solution concentration which avoids invoking classic kinetic theory to relate a rate to a specific thermodynamic activity and which avoids uncertainty associated with mass transfer phenomena.

Original languageEnglish (US)
Pages (from-to)5903-5908
Number of pages6
JournalAnalytical Chemistry
Volume90
Issue number9
DOIs
StatePublished - May 1 2018

ASJC Scopus subject areas

  • Analytical Chemistry

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