An in vivo probe based on mechanically strong but structurally small carbon electrodes with an appreciable surface area

M. McNally, D. K Y Wong*

*Corresponding author for this work

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Physically small carbon electrodes were fabricated by pyrolyzing acetylene in a nitrogen atmosphere using pulled quartz capillaries as the supporting substrate. A carbon disk geometry was obtained when a parallel flow of acetylene (50 kPa) and nitrogen (10 mL min -1) was introduced into the system. Further, carbon was found to deposit at the tip and on the shank of the quartz capillaries when the nitrogen flow rate was increased (80 mL min -1), yielding an approximately cylindrical geometry. A series of electrochemical and spectroscopic analyses was carried out to examine the type of carbon surface obtained by pyrolysis of acetylene. The results suggested that a surface consisting of an almost defect-free highly oriented pyrolytic graphite type structure was formed by the pyrolyzed acetylene. However, this contradicts the kinetically reversible electron transfer observed for dopamine oxidation at these electrodes. Meanwhile, the nonpolar and relatively oxygen-free characteristics indicate that these electrodes also behave similarly to a hydrogenated carbon surface. The formation of a hydrogenated carbon-type surface may be plausible as a result of the attack on the carbon surface by a surplus of hydrogen produced by the pyrolysis of acetylene to form graphitic carbon. These characteristics are expected to aid in reducing electrode fouling, which is often encountered in electrochemical detection of neurotransmitters in vivo. In conjunction with a miniature physical dimension, their appreciable surface area and enhanced mechanical strength make these carbon electrodes well suited to the detection of neurotransmitters in vivo.

Original languageEnglish
Pages (from-to)4793-4800
Number of pages8
JournalAnalytical Chemistry
Volume73
Issue number20
DOIs
Publication statusPublished - 15 Oct 2001

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