title: Ion-selective optodes measure extracellular potassium flux in excitable cells.
abstract: Optodes have been used for detection of ionic concentrations and fluxes for several years. However, their uses in biomedical applications have not yet been fully explored. This study investigates optodes as a potential sensor platform for monitoring cellular ion flux with attendant implications in the field of drug screening and toxicology. A prototype system was developed to quantitatively measure extracellular potassium flux from a monolayer of cardiomyocytes. Optodes were created and immobilized on a glass coverslip for fluorescent imaging. The system detected potassium (K(+) ) ion flux during the repolarization phase of the cardiac action potential and further detected a decrease in the magnitude of the flux in the presence of a known K(+) channel inhibitor by optically monitoring local K(+) ion concentrations during field stimulation of the cardiomyocyte monolayer.
authors: Biomedical Engineering Group, The Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA, USA.
authors: Daniel I
authors: DI
authors: Harjes
authors: J Matthew
authors: JM
authors: Dubach
authors: Anthony
authors: A
authors: Rosenzweig
authors: Saumya
authors: S
authors: Das
authors: Heather A
authors: HA
authors: Clark
references: Anal Chem. 1999 Nov 1;71(21):4831-6
references: 10565274
references: Nature. 1995 Aug 24;376(6542):683-5
references: 7651517
references: Cardiology. 2009;113(1):59-65
references: 18984955
references: Nano Lett. 2007 Jun;7(6):1827-31
references: 17497824
references: Anal Chem. 1999 Nov 1;71(21):4837-43
references: 10565275
references: Prog Biophys Mol Biol. 2008 Oct-Nov;98(2-3):137-48
references: 19027781
references: Chem Rev. 1997 Dec 18;97(8):3083-3132
references: 11851486
references: Circ Res. 2006 Jul 7;99(1):15-24
references: 16763166
references: Curr Drug Metab. 2008 Nov;9(9):965-70
references: 18991593