A dual signal-amplified electrochemiluminescence immunosensor based on core-shell CeO-Au@Pt nanosphere for procalcitonin detection.

A dual signal-amplified sandwich electrochemiluminescence (ECL) immunosensor was fabricated for trace detection of procalcitonin (PCT). CeO-Au@Pt composed of sea urchin-like Au@Pt nanoparticles coated on CeO hollow nanospheres was immobilized on electrode surface to electrochemically catalyze HO to produce a large number of superoxide anion (O). The immunosensor was prepared by linking the capture antibody on immobilized CeO-Au@Pt with heptapeptide (HWRGWVC), which could maintain the activity of the antibody. The prepared Au star@BSA was used to bind abundant luminol for labeling the secondary antibody (Ab). Upon the sandwich-typed immunoreactions, the O could react with the introduced luminol on the immunosensor surface to produce strong ECL intensity. With an outstanding linear detection range and a low detection limit of 17 fg/mL, the ECL immunosensor permitted ultrasensitive detection of PCT at a low HO concentration and demonstrated its high application potential in the clinical assay.