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

Abstract A novel electrochemiluminescence (ECL) aptasensor based on CdS–MoS 2 nanocomposites was designed for detection of immunoglobulin E (IgE). The flowerlike CdS–MoS 2 composites were synthesized through a simple one-pot hydrothermal method. The CdS–MoS 2 composites were immobilized on glassy carbon electrode surface as ECL emitter attached a complementary ssDNA (NH 2 –ssDNA) of IgE. IgE aptamer (T-Apt) with DNAzyme–AuNPs can hybridize with NH 2 –ssDNA to form dsDNA. The DNAzyme with horseradish peroxidase-like activity could electrocatalyze the reduction of H 2 O 2 , the coreactant of CdS–MoS 2 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 H 2 O 2 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–MoS 2 composites and DNAzyme features high sensitivity, good selectivity and wide linear range, suggesting the potential applications in biochemical analysis.