3D origami electrochemiluminescence immunodevice based on porous silver-paper electrode and nanoporous silver double-assisted signal amplification

A highly sensitive electrochemiluminescence (ECL) immunosensor combined with a 3D origami device for detection of carcinoembryonic antigen (CEA) was developed based on novel porous silver nanoparticles modified paper working electrode (Ag-PWE) as sensor platform and CdTe quantum dots functionalized nanoporous silver (QDs/NPS) as signal amplification label. The microfluidic origami device was fabricated by directly screen-printed electrodes on wax-patterned cellulose paper in bulk. The Ag-PWE was fabricated by a seed-mediated growth approach and served as an effective matrix for antibody attachment with good bioactivity, and stability. The ECL nanoprobe (Ab2/QDs/NPS) was designed by covalent assembly of signal antibodies (Ab2) on QDs/NPS. After a sandwich immunoreaction, the functionalized NPS labels were captured onto the Ag-PWE surface. On the basis of the considerably amplified ECL signal and sandwich-type format, the proposed method successfully fulfilled the highly sensitive detection of CEA with a linear range of 0.5 pg mL−1 to 20 ng mL−1 with a detection limit of 0.12 pg mL−1. This facile origami ECL immunodevice exhibited high sensitivity, specificity and excellent performance in real human serum assay, and could be applied in point-of-care testing of other tumor markers for remote regions and developing countries.