Direct electron transfer of cytochrome C and its electrocatalytic properties on multiwalled carbon nanotubes/ciprofloxacin films

S. Ashok Kumar, Sea Fue Wang, Chun Ting Yeh, His Chuan Lu, Jen Chang Yang, Yu Tsern Chang

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


In this study, stable and homogenous thin films of multiwalled carbon nanotubes (MWCNTs) were obtained on conducting surface using ciprofloxacin (CF, fluoroquinolone antibiotic) as an effective-dispersing agent. Further, MWCNTs/CF film modified electrodes (glassy carbon and indium tin oxide-coated glass electrode) are used successfully to study the direct electrochemistry of proteins. Here, cytochrome C (Cyt-C) was used as a model protein for investigation. A MWCNTs/CF film modified electrode was used as a biocompatible material for immobilization of Cyt-C from a neutral buffer solution (pH 7.2) using cyclic voltammetry (CV). Interestingly, Cyt-C retained its native state on the MWCNTs/CF film. The Cyt-C adsorbed MWCNTs/CF film was characterized by scanning electron microscopy (SEM), UV-visible spectrophotometry (UV-vis) and CV. SEM images showed the evidence for the adsorption of Cyt-C on the MWCNTs/CF film, and UV-vis spectrum confirmed that Cyt-C was in its native state on MWCNTs/CF film. Using CV, it was found that the electrochemical signal of Cyt-C was highly stable in the neutral buffer solution and its redox peak potential was pH dependent. The formal potential (-0.27 V) and electron transfer rate constant (13±1 s -1) were calculated for Cyt-C on MWCNTs/CF film modified electrode. A potential application of the Cyt-C/MWCNTs/CF electrode as a biosensor to monitor H 2O 2 has been investigated. The steady-state current response increases linearly with H 2O 2 concentration from 2×10 -6 to 7.8×10 -5 M. The detection limit for determination of H 2O 2 has been found to be 1.0×10 -6 M (S/N=3). Thus, Cyt-C/MWCNTs/CF film modified electrode can be used as a biosensing material for sensor applications.

Original languageEnglish
Pages (from-to)2129-2135
Number of pages7
JournalJournal of Solid State Electrochemistry
Issue number11
Publication statusPublished - Nov 2010


  • Biosensor
  • Carbon nanotubes
  • Cytochrome C
  • Hydrogen peroxide sensor

ASJC Scopus subject areas

  • Electrochemistry
  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • General Materials Science


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