Aptamer-antibody sandwich assay for cytochrome c employing a MWCNT platform and the electrochemical impedance technique
Ocaña Tejada, Cristina (Universitat Autònoma de Barcelona. Departament de Química)
Lukic, Sonja (University of Regensburg. Institut of Analytical Chemistry, Chemo- and Biosensors)
Valle Zafra, Manuel del (Universitat Autònoma de Barcelona. Departament de Química)

Date:	2015
Abstract:	We report on a sensitive aptamer-antibody interaction-based assay for cytochrome c (Cytc) 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 (Cytc). 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.
Grants:	European Commission 264772 Ministerio de Ciencia e Innovación CTQ2013-41577-P
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Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Aptamer ; Sandwich ; Cytochrome c ; SEM ; Gold-nanoparticles electrochemical impedance spectroscopy
Published in:	Mikrochimica acta, Vol. 182, Issue 11 (August 2015) , p. 2045-2053, ISSN 1436-5073

DOI: 10.1007/s00604-015-1540-6

Post-print 22 p, 1.4 MB

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