A dual-potential electrochemiluminescence sensor for ratiometric detection of carcinoembryonic antigen based on single luminophor

Ratiometric electrochemiluminescence (ECL) assays have attracted widespread attentions in biosensing owing to their precise measurements by eliminating the environmental interferences. However, they mostly needed two eligible luminophors, increasing the complexity of the systems and limiting their practical applications. Herein, using luminol as single luminophor, a dual-potential ratiometric ECL strategy was proposed to detect carcinoembryonic antigen (CEA). The luminol exhibited cathodic and anodic emissions on graphene-ionic liquid-platinum (GR-IL-Pt) composites and Ti 3 C 2 MXenes-Au NPs hybrids, respectively. Then, a sandwich ECL sensor was fabricated using GR-IL-Pt composites as matrix to immobilize the primary antibodies of CEA and Ti 3 C 2 MXenes-Au NPs hybrids as platform to load the secondary antibodies. With the presence of CEA, the ratio of anodic ECL to cathodic ECL (ECL anodic /ECL cathodic ) increased obviously, realizing sensitive ratiometric detection of CEA. In addition, the ECL anodic /ECL cathodic was independent with the concentrations of H 2 O 2 , greatly improving the test reliability. The developed ECL sensor exhibited a sensitive detection toward CEA, performing a wide linearity in the range of 0.1 pg mL −1 - 10 ng mL −1 with a low detection limit of 34.58 fg mL -1 (S/N = 3). Furthermore, this strategy exhibited a good practicality to detect CEA in human serums, providing a promising strategy in ECL bioanalysis.