A dual signal-amplified electrochemiluminescence immunosensor based on core-shell CeO2-Au@Pt nanosphere for procalcitonin detection

A dual signal-amplified sandwich electrochemiluminescence (ECL) immunosensor was fabricated for trace detection of procalcitonin (PCT). CeO 2 -Au@Pt composed of sea urchin-like Au@Pt nanoparticles coated on CeO 2 hollow nanospheres was immobilized on electrode surface to electrochemically catalyze H 2 O 2 to produce a large number of superoxide anion (O 2 •− ). The immunosensor was prepared by linking the capture antibody on immobilized CeO 2 -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 2 ). Upon the sandwich-typed immunoreactions, the O 2 •− 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 H 2 O 2 concentration and demonstrated its high application potential in the clinical assay. Graphical abstract