An electrochemiluminescence aptasensor based on CdSe/ZnS functionalized MoS2 and enzymatic biocatalytic precipitation for sensitive detection of immunoglobulin E

Abstract

A novel competitive electrochemiluminescence (ECL) aptasensor based on CdSe/ZnS quantum dots (QDs) functionalized MoS2 modified electrode was developed for sensitive immunoglobulin E (IgE) detection using horseradish peroxidase (HRP) catalyzed biocatalytic precipitation (BCP) for signal quenching. MoS2 was introduced to load QDs using PDDA as a bridge to form the MoS2-QDs composites which were employed as matrix for the immobilization of the complementary DNA (cDNA) of IgE aptamer, then HRP functionalized gold nanoparticles (AuNPs) labeled aptamer (aptamer-AuNPs-HRP) was designed as the signal probe for the aptasensor, the presence of HRP would stimulate the BCP onto the electrode surface for its insulating effect on ECL signal, thereby impairing the ECL emission. In the presence of IgE, the signal probe would capture IgE to form conjugation, released from the electrode accompanying decrease of HRP and increase of ECL intensity. Improved sensitivity is achieved through using the signal probe. This fabricated aptasensor displays a liner range from 0.5pM to 0.5nM with a detection limit of 0.18pM (S/N=3). Moreover, eight human sera samples were analyzed with recoveries of 85.0–107.5%. The present strategy provides a promising method for the future development of ECL aptasensor for advanced biochemical analysis.