An ultrasensitive luminol cathodic electrochemiluminescence probe with highly porous Pt on ionic liquid functionalized graphene film as platform for carcinoembryonic antigen sensing.

The low-potential electrochemiluminescence (ECL) sensors based on cathodic light emission of luminol have caused more and more concerns due to their good stability and reproducibility. In this work, highly porous platinum (Pt) nanostructures on ionic liquid functionalized graphene film (GR-IL/pPt) were prepared as platform to construct a label-free ECL sensor for the detection of carcinoembryonic antigen (CEA). Due to their good biocompatibility, excellent electrocatalytic activity and highly porous structure, the as-prepared GR-IL/pPt composites benefited amplified cathodic ECL signal of luminol and high loading density of the CEA antibody. After CEA was incubated with the CEA antibody, the cathodic ECL signal of luminol decreased thanks to the less conductive immunocomplex. The proposed ECL immunosensor realized high sensitivity for CEA detection with a wide linear range from 0.001 fg mL-1 to 1 ng mL-1 and an extremely low detection limit of 0.0003 fg mL-1 (S/N = 3). Moreover, the sensor showed good specificity, stability and reproducibility, indicating that the provided strategy had a promising potential in clinical detection.