A reusable impedimetric aptasensor for detection of thrombin employing a graphite-epoxy composite electrode

Cristina Ocaña, Mercè Pacios, Manel del Valle

Research output: Contribution to journalArticleResearchpeer-review

26 Citations (Scopus)

Abstract

Here, we report the application of a label-free electrochemical aptasensor based on a graphite-epoxy composite electrode for the detection of thrombin; in this work, aptamers were immobilized onto the electrodes surface using wet physical adsorption. The detection principle is based on the changes of the interfacial properties of the electrode; these were probed in the presence of the reversible redox couple [Fe(CN)6]3-/[Fe(CN)6]4- using impedance measurements. The electrode surface was partially blocked due to formation of aptamer-thrombin complex, resulting in an increase of the interfacial electron-transfer resistance detected by Electrochemical Impedance Spectroscopy (EIS). The aptasensor showed a linear response for thrombin in the range of 7.5 pM to 75 pM and a detection limit of 4.5 pM. The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution at 42 °C, showing its operation for different cycles. The interference response caused by main proteins in serum has been characterized. © 2012 by the authors.
Original languageEnglish
Pages (from-to)3037-3048
JournalSensors
Volume12
Issue number3
DOIs
Publication statusPublished - 1 Mar 2012

Keywords

  • Adsorption
  • Aptamer
  • Electrochemical impedance spectroscopy
  • Labeless
  • Thrombin

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