An electrochemiluminescence aptasensor based on flowerlike CdS-MoS2 composites and DNAzyme for detection of immunoglobulin E

A novel electrochemiluminescence (ECL) aptasensor based on CdS-MoS2 nanocomposites was designed for detection of immunoglobulin E (IgE). The flowerlike CdS-MoS2 composites were synthesized through a simple one-pot hydrothermal method. The CdS-MoS2 composites were immobilized on glassy carbon electrode surface as ECL emitter attached a complementary ssDNA (NH2-ssDNA) of IgE. IgE aptamer (T-Apt) with DNAzyme-AuNPs can hybridize with NH2-ssDNA to form dsDNA. The DNAzyme with horseradish peroxidase-like activity could electrocatalyze the reduction of H2O2, the coreactant of CdS-MoS2 ECL emission, leading to an obvious ECL quenching. In the presence of IgE, IgE conjugated with DNAzyme-AuNPs-T-Apt and thereafter the conjugations released, which decreased the consumption of H2O2 by DNAzyme-AuNPs, produced an increased ECL signal. The changed ECL intensity is proportional to concentration of IgE in the range of 0.001-10.0 nM with the detection limit of 0.34 pM (S/N=3). The prepared aptasensor has been applied to determination of IgE in human serum samples. The recoveries of IgE in human serum samples are between 83.0% and 108% with the RSD values no more than 3.8%. The developed sensor with CdS-MoS2 composites and DNAzyme features high sensitivity, good selectivity and wide linear range, suggesting the potential applications in biochemical analysis. (C) 2015 Elsevier B.V. All rights reserved.