title: Signal Amplification Strategy Based on TiO2-Nanotube Layers and Nanobeads Carrying Quantum Dots for Electrochemiluminescent Immunosensors.
abstract: Self-organized TiO2-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 TiO2 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 TiO2-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 TiO2 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).
authors.affiliation: College of Sciences, Northeastern University Shenyang 110004 (P. R. China) E-mail: yysong@mail.neu.edu.cn.
authors.forename: Zhi-Da
authors.initials: ZD
authors.lastname: Gao
authors.affiliation: College of Sciences, Northeastern University Shenyang 110004 (P. R. China) E-mail: yysong@mail.neu.edu.cn.
authors.forename: Qian-Lan
authors.initials: QL
authors.lastname: Zhuang
authors.affiliation: College of Sciences, Northeastern University Shenyang 110004 (P. R. China) E-mail: yysong@mail.neu.edu.cn.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Song
authors.affiliation: Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremberg Martensstrasse 7, 91058 Erlangen (Germany) E-mail: schmuki@ww.uni-erlangen.de.
authors.forename: Kiyoung
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremberg Martensstrasse 7, 91058 Erlangen (Germany) E-mail: schmuki@ww.uni-erlangen.de.
authors.forename: Patrik
authors.initials: P
authors.lastname: Schmuki
keywords: TiO2 nanotubes; electrochemiluminescence; quantum dots; signal amplification