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Redox‐Filled Carbon‐Fiber Microelectrodes for Single‐Cell Exocytosis
Author(s) -
Cox Jonathan T.,
Gunderson Christopher G.,
Zhang Bo
Publication year - 2013
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201300255
Subject(s) - microelectrode , redox , electrolyte , exocytosis , electrode , kinetic energy , materials science , chemistry , analytical chemistry (journal) , biophysics , chemical engineering , nanotechnology , inorganic chemistry , chromatography , membrane , biochemistry , biology , physics , quantum mechanics , engineering
Carbon‐fiber microelectrodes (CFEs) are the primary electroanalytical tool in single‐cell exocytosis and in vivo studies. Here we report a new study on the kinetic properties of electrolyte‐filled CFEs in single‐cell measurements and demonstrate that the addition of outer sphere redox species, such as Fe(CN) 6 3− and Ru(NH 3 ) 6 3+ , in the backfill electrolyte solution can greatly enhance the kinetic response of CFEs. We show that at 750 mV, a voltage normally applied for detection of dopamine, the presence of fast outer sphere redox species in the backfilling solution significantly enhances the kinetic response of CFEs toward fast dopamine detection at single PC12 cells. Moreover, we also demonstrate that the use of Fe(CN) 6 3− in the backfilling solution has enabled direct measurement of dopamine at applied voltages as low as 200 mV. This kinetic enhancement is believed to be due to faster electron‐transfer kinetics on the coupling pole as compared to the sluggish reduction of oxygen. We anticipate that such redox‐filled CFE ultramicroelectrodes will find many useful applications in single cell exocytosis and in vivo sensing.