Open AccessSignal Amplification Strategy Based on TiO 2 ‐Nanotube Layers and Nanobeads Carrying Quantum Dots for Electrochemiluminescent Immunosensors
Author(s) -
Gao ZhiDa,
Zhuang QianLan,
Song YanYan,
Lee Kiyoung,
Schmuki Patrik
Publication year - 2013
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201300003
Subject(s) - electrochemiluminescence , quantum dot , triethoxysilane , detection limit , nanotube , materials science , nanotechnology , immunoassay , electrode , chemistry , chromatography , carbon nanotube , composite material , antibody , immunology , biology
Self‐organized TiO 2 ‐nanotube layers can be used for immunoassay‐type sensing in combination with amplifying CdTe labels in a direct and very sensitive electrochemiluminescent (ECL) configuration. Key properties for this method are the conductivity of the TiO 2 nanotubes, and their transparency for light emitted from the CdTe labels at approximately 2.4 eV. To demonstrate the potential of this platform, we constructed a sandwich‐type immunoassay onto the TiO 2 ‐nanotube wall with a layer of (3‐aminopropyl)triethoxysilane as the cross‐linker for antibody immobilization. For the counter part of the sandwich, we created an amplification system consisting of TiO 2 nanobeads carrying the secondary antibody and multiple CdTe quantum dots (multiQD). For antigen (IgG) detection, we find that this combination of 3D transparent electrode with multiQD labels allows for an ECL detection limit of 0.05 pg mL −1 and a linearity of the signal in the range of 0.1–10 8 pg mL −1 .