A comparative study of carbon fiber-based microelectrodes for the measurement of nitric oxide in brain tissue

Ricardo M. Santos, Cátia F. Lourenço, Ana P. Piedade, Rodney Andrews, François Pomerleau, Peter Huettl, Greg A. Gerhardt, João Laranjinha, Rui M. Barbosa

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


The measurement of Nitric oxide ({radical dot}NO) in real-time has been a major concern due to the involvement of this ubiquitous free radical modulator in several physiological and pathological pathways in tissues. Here we performed a study aiming at evaluating different types of carbon fibers, namely Textron, Amoco, Courtaulds and carbon nanotubes (University of Kentucky) covered with Nafion®/o-phenylenediamine (o-PD) for {radical dot}NO measurement in terms of sensitivity, LOD, response time and selectivity against major potential interferents in the brain (ascorbate, nitrite and dopamine). The results indicate that, as compared with the other carbon fibers and nanotubes, Textron carbon fiber microelectrodes coated with two layers of Nafion® and o-PD exhibited better characteristics for {radical dot}NO measurement as they are highly selective against ascorbate (>30,000:1), nitrite (>2000:1) and dopamine (>80:1). These coated Textron microelectrodes showed an average sensitivity of 341 ± 120 pA/μM and a detection limit of 16 ± 11 nM. The better performance of the Textron fibers is likely related to a stronger adhesion or more uniform coating of the Nafion® and o-PD polymers to the fiber surface. In addition, the background current of the Textron carbon fibers is low, contributing to the excellent signal-to-noise for detection of {radical dot}NO.

Original languageEnglish
Pages (from-to)704-709
Number of pages6
JournalBiosensors and Bioelectronics
Issue number4
StatePublished - Dec 1 2008

Bibliographical note

Funding Information:
AP acknowledges financial support to Fundação para a Ciência e a Tecnologia (SFRH/BPD/27139/2006).

Funding Information:
This work was supported by a grant from Fundação para a Ciência e Tecnologia PTDC/AGR-ALI/71262/2006.

Funding Information:
RA acknowledges the financial support of the U.S. Department of Energy, under award no. DE-FC26-03NT41874. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the DOE.


  • Carbon fiber
  • Carbon nanotubes
  • Microelectrode
  • Nafion
  • Nitric oxide
  • o-phenylenediamine

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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