Aptamer-antibody sandwich assay for cytochrome c employing an MWCNT platform and electrochemical impedance

Cristina Ocaña, Sonja Lukic, Manel del Valle

Research output: Contribution to journalArticleResearchpeer-review

26 Citations (Scopus)

Abstract

© 2015, Springer-Verlag Wien. We report on a sensitive aptamer-antibody interaction-based assay for cytochrome c (Cyt c) using electrochemical impedance. 4-Amino benzoic acid is used for the oriented immobilization of aminated aptamers onto multi-walled carbon nanotubes on the surface of a screen-printed electrode via electrochemical grafting. Impedance was measured in a solution containing the redox system ferro/ferricyanide. The change in interfacial charge transfer resistance (R ct ) experienced by the redox marker was recorded to confirm the formation of a complex between aptamer and the target (Cyt c). A biotinylated antibody against cytochrome c was then used in a sandwich type of assay. The addition of streptavidin conjugated to gold nanoparticles and signal enhancement by treatment with silver led to a further increase in Rct. Under optimized conditions, a detection limit as low as 12 pM was obtained. Cross-reactivity against other serum proteins including fibrinogen, BSA and immunoglobulin G demonstrated improved selectivity.
Original languageEnglish
Pages (from-to)2045-2053
JournalMicrochimica Acta
Volume182
Issue number11-12
DOIs
Publication statusPublished - 1 Aug 2015

Keywords

  • Aptamer
  • Cytochrome c
  • Gold-nanoparticles electrochemical impedance spectroscopy
  • Sandwich
  • SEM

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