Hot electron induced cathodic electrochemiluminescence at AuSb alloy electrode for fabricating immunosensor with self-assembled monolayers.
Thin antimony oxide covered AuSb alloy electrode was firstly found to be an excellent cold cathode for generating hot electrons during cathodic pulse polarization. Owing to the injection of hot electrons and the subsequent generation of hydrated electrons, fluorescein iso-thiocyanate (FITC) that cannot be excited in common ECL was cathodically excited at the alloy electrode. Self-assembled thiol monolayers were formed on the electrode surface due to the presence of Au in the alloy, to which strepavidin was covalently bound, and then biotinylated antibody was immobilized through the strepavidin-biotin interaction. As a simple model, an immunosensor for the detection of human IgG (hIgG) using FITC as labeling agent was fabricated. ECL signals were responsive to the amount of hIgG bounded to the immunosensor. The ECL intensity was linearly changed with the logarithm of hIgG concentration in the range of 1.0-1000 ng mL(-1), and the detection limit was ca. 0.3 ng mL(-1) (S/N=3). The proposed immunosensor showed a broad linear range (three magnitudes), good reproducibility and stability, which is promising in detecting FITC-based labels in various types of bioaffinity assays.
Wu
Ai-Hong
AH
Key Laboratory of Analysis and Detection for Food Safety Ministry of Education, and Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, China.
Sun
Jian-Jun
JJ
Fang
Yi-Min
YM
Su
Xiu-Li
XL
Chen
Guo-Nan
GN
D000965:Antimony / Q000737:chemistry*; D015374:Biosensing Techniques; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D049449:Luminescence
D006046:Gold; D000965:Antimony