Sandwich-configuration electrochemiluminescence biosensor based on Ag nanocubes-polyamidoamine dendrimer-luminol nanocomposite for Con A detection

A sandwich-configuration electrochemiluminescence (ECL) biosensor was constructed with Ag nanocubes-polyamidoamine dendrimer-luminol-glucose oxidase (AgNCs-PAMAM-luminol-GOx) as the signal probe for detecting concanavalin A (Con A). In brief, three-dimensional molybdenum disulfide-polyaniline (3D-MoS2-PANI) nanoflowers were prepared as the matrix for combining phenoxy functionalized dextran (DexP) via π-π interaction. Here, DexP served as a recognition element for binding Con A. Then, AgNCs-PAMAM-luminol-GOx nanocomposite was bound to the bind site of Con A through specific carbohydrate-Con A interaction, thus achieving a solid-state luminol biosensor. Herein, DexP, Con A and AgNCs-PAMAM-luminol-GOx formed a sandwich-type configuration. AgNCs-PAMAM could immobilize large amounts of luminescence reagent luminol. Importantly, AgNCs and MoS2 could catalyze H2O2 to generate abundant reactive oxygen species (ROSs), further enhancing the ECL intensity. As a result, such a sandwiched ECL biosensor exhibited two wide linear response ranges from 0.005 to 0.1 ng/mL and 0.1 to 20 ng/mL for Con A detection.