Simultaneous measurements of ascorbate and glutamate in vivo in the rat brain using carbon fiber nanocomposite sensors and microbiosensor arrays

Nuno R. Ferreira, Ana Ledo, João Laranjinha, Greg A. Gerhardt, Rui M. Barbosa

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Nanocomposite sensors consisting of carbon fiber microelectrodes modified with Nafion® and carbon nanotubes, and ceramic-based microelectrode biosensor arrays were used to measure ascorbate and glutamate in the brain with high spatial, temporal and chemical resolution. Nanocomposite sensors displayed electrocatalytic properties towards ascorbate oxidation, translated into a negative shift from +0.20 V to −0.05 V vs. Ag/AgCl, as well as a significant increase (10-fold) of electroactive surface area. The estimated average basal concentration of ascorbate in vivo in the CA1, CA3 and dentate gyrus (DG) sub regions of the hippocampus were 276 ± 60 μM (n = 10), 183 ± 30 μM (n = 10) and 133 ± 42 μM (n = 10), respectively. The glutamate microbiosensor arrays showed a high sensitivity of 5.3 ± 0.8 pA μM−1 (n = 18), and LOD of 204 ± 32 nM (n = 10), and t50% response time of 0.9 ± 0.02 s (n = 6) and high selectivity against major interferents. The simultaneous and real-time measurements of glutamate and ascorbate in the hippocampus of anesthetized rats following local stimulus with KCl or glutamate revealed a dynamic interaction between the two neurochemicals.

Original languageEnglish
Pages (from-to)142-150
Number of pages9
JournalBioelectrochemistry
Volume121
DOIs
StatePublished - Jun 2018

Bibliographical note

Publisher Copyright:
© 2018 Elsevier B.V.

Keywords

  • Ascorbate
  • Carbon nanotubes
  • Glutamate
  • In vivo monitoring
  • Microelectrode arrays

ASJC Scopus subject areas

  • Biophysics
  • Physical and Theoretical Chemistry
  • Electrochemistry

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