A label-free impedimetric immunosensor based on covalent immobilization of anti-E. Coliantibody via a copper-catalyzed azide-alkyne cycloaddition reaction

摘要

In this article, an original method is proposed for address and covalent immobilization of anti-E. coliantibodies on a screen-printed electrode (SPE). The method is based on a copper-catalyzed "click" reaction between a polyvinylbenzylazide (PVBA) film electrochemically deposited on the electrode surface and acetylene fragments of propargyl-N-hydroxysuccinimide ester. The products of electrochemical oxidation of copper particles incorporated in the polymer film on the electrode were first used for catalysis of the click reaction. This approach allowed us to reduce the immobilization time from a few hours for conventional methods to just 30 min, and to prevent denaturation of the immunoreceptor. The modified electrodes were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Based on the results obtained, a label-free impedimetric immunosensor forE. colidetection was developed. The detection limit of the immunosensor was estimated as 6.3 CFU/ml, with a linear range of 10(3)-10(6) CFU/ml. The immunosensor demonstrated good stability during 30 days of storage in phosphate buffer solution (PBS, pH 7) and selectivity toward excessStaphylococcus aureusbacteria.