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 language | English |
|---|---|
| Pages (from-to) | 2045-2053 |
| Journal | Microchimica Acta |
| Volume | 182 |
| Issue number | 11-12 |
| DOIs | |
| Publication status | Published - 1 Aug 2015 |
Keywords
- Aptamer
- Cytochrome c
- Gold-nanoparticles electrochemical impedance spectroscopy
- SEM
- Sandwich