Microchimica Acta

, Volume 182, Issue 11, pp 2045–2053

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

Original Paper

DOI: 10.1007/s00604-015-1540-6

Cite this article as:
Ocaña, C., Lukic, S. & del Valle, M. Microchim Acta (2015) 182: 2045. doi:10.1007/s00604-015-1540-6

Abstract

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 (Rct) 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.

Graphical Abstract

Sensitive and selective assay for cytochrome c protein using aptamer linked to multi-walled carbon nanotube screen printed electrode via diazonium electrochemical grafting and specific biotinylated antibody to improve selectivity. Detection can be based on electrochemical impedance spectroscopy, or using a streptavidin-gold nanoparticle conjugate.

Keywords

Aptamer Sandwich Cytochrome c SEM Gold-nanoparticles electrochemical impedance spectroscopy 

Supplementary material

604_2015_1540_MOESM1_ESM.doc (78 kb)
ESM 1(DOC 78 kb)

Copyright information

© Springer-Verlag Wien 2015

Authors and Affiliations

  • Cristina Ocaña
    • 1
  • Sonja Lukic
    • 2
  • Manel del Valle
    • 1
  1. 1.Sensors and Biosensors Group, Department of ChemistryUniversitat Autònoma de BarcelonaBarcelonaSpain
  2. 2.Institute of Analytical Chemistry, Chemo- and BiosensorsUniversity of RegensburgRegensburgGermany

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