1.School of Chemistry and Chemical Engineering,University of Jinan,Jinan,China
Abstract:
The interference by dissolved oxygen is an obstacle in electrochemical immunoassays. The authors are reporting here on a method that employs a working potential that is below the reduction potential for oxygen and hence is not interfered by oxygen/air. Ternary Pt-Co-Cu nanodendrites were prepared by a one-pot reaction. They were placed on a glassy carbon electrode (GCE) modified with gold nanoparticles (AuNPs) where they showed excellent catalytic activity toward the reduction of hydrogen peroxide at a reduction potential of ?0.015 V (vs. SCE). Dissolved oxygen, in contrast, is not reduced at this potential. In order to obtain a sandwich-type of voltammetric immunosensor, antibody against insulin (Ab1) immobilized on the AuNPs on the GCE. The secondary antibody (Ab2) was labeled with Pt-Co-Cu nanodendrites as signal marker for signal amplification. After adding hydrogen peroxide, its catalytic oxidation by the immunosensor depends on its loading with insulin. Hence, insulin can be quantified due to the positive correlation that exists between current and the concentration of ternary Pt-Co-Cu nanodendrites on the electrode. The sensor has a linear response in the 0.2 pM to 2 nM insulin concentration range, with a 0.08 pM detection limit. The assay is well reproducible, acceptably selective, and the sensor is fairly stable over time.
Graphical abstract One-pot synthesis of ternary Pt-Co-Cu nanodendrites for oxygen interference-free electrochemical detection of insulin. GCE (glassy carbon electrode). Pt-Co-Cu NP (Pt-Co-Cu nanoparticles). BSA (bovine serum albumin). Ab1 (coating antibody). Ab2 (labeling antibody). The sandwich-type electrochemical immunosensor has been used for detecting insulin with high sensitivity, which is based on Au nanoparticles for biomolecular immobilization and the one-pot synthesis of ternary Pt-Co-Cu nanodendrites as label enhancer.
