Paper-based electrochemiluminescence immunodevice for carcinoembryonic antigen using nanoporous gold-chitosan hybrids and graphene quantum dots functionalized Au@Pt

A highly sensitive 3D origami device combined with electrochemiluminescence (ECL) immunosensor was introduced for sensitive point-of-care testing of carcinoembryonic antigen (CEA). This immunodevice was developed based on nanoporous gold/chitosan modified paper working electrode (NGC-PWE) as sensor platform and green-luminescent graphene quantum dots (GQDs) functionalized Au@Pt core-shell nanoparticles (GQDs/Au@Pt) as signal label. Firstly, the origami device was fabricated by directly screen-printing electrodes on wax-patterned pure cellulose paper. Secondly, the NGC hybrids were prepared and introduced for binding of primary antibody with high loading amount. The ECL nanoprobe (Ab2/GQDs/Au@Pt) was designed by covalent assembly of signal antibody (Ab2) on GQDs tagged Au@Pt core-shell nanoparticles. After a sandwich-type immunoreaction, the GQDs/Au@Pt labels were captured onto the NGC-PWE surface. The amplified ECL signals were achieved by efficient catalysis of the glucose oxidase (GOx) towards the oxidation of glucose to in situ generate H2O2 as coreactant and the enhancement of Au@Pt to the ECL reaction of GQDs-H2O2. Under the optimized experimental conditions, the proposed strategy exhibited excellent high sensitivity for the determination of CEA ranging from 1.0pgmL−1 to 10ngmL−1 with the detection limit of 0.6pgmL−1. The assay results of CEA in clinical serum samples were in a good agreement with the commercial ECL single-analyte tests. The proposed enhanced ECL immunosensor may become a promising technique for detection of other tumor markers.