Electrochemical impedance spectroscopy biosensor for detection of active botulinum neurotoxin

Jennifer Halliwell, Alison C. Savage, Nicholas Buckley, Christopher Gwenin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)
1 Downloads (Pure)


The standard method for the detection of botulinum neurotoxin is currently the mouse bioassay which is considered to be the most reliable method for the detection of the active form of this toxin. Despite this it is a time-consuming and expensive assay to run and as such many alternative assays have recently been proposed. Herein we report the development of two electrochemical assays for the detection of active botulinum neurotoxin in a pharmaceutical sample. Gold electrodes were modified with self-assembled monolayers of the SNARE protein SNAP-25 which is selectively cleaved by active botulinum neurotoxin A. Cyclic voltammetry and electrochemical impedance spectroscopy were performed on the modified working electrodes to observe changes to the layer on addition of the toxin. Both methods were able to distinguish the difference between the presence of the active toxin and a placebo containing the excipients of the pharmaceutical product. The electrochemical impedance spectroscopy assay also allowed for detection of the active toxin at concentrations as low as 25. fg/ml, with results being obtained in under an hour outperforming the mouse bioassay.

Original languageEnglish
Pages (from-to)12-15
Number of pages4
JournalSensing and Bio-Sensing Research
Early online date13 Oct 2014
Publication statusPublished - 1 Dec 2014
Externally publishedYes


  • Electrochemical impedance spectroscopy
  • Cyclic voltammetry
  • Botulinum neurotoxin
  • SNAP-25


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