Ternary Electrochemiluminescence Nanostructure of Au Nanoclusters as a Highly Efficient Signal Label for Ultrasensitive Detection of Cancer Biomarkers

Herein, the Au nanoclusters (Au NCs) functionalized ternary nanostructure with significant electrochemiluminescence (ECL) emission was first proposed to fabricate an ultrasensitive immunosensor for carcinoembryonic antigen (CEA) detection, which was established by combining bovine serum albumin (BSA) templated Au NCs as the luminophor, tris(3-aminoethyl)amine (TAEA) as the coreactant, and Pd@CuO nanomaterial as the coreaction accelerator via covalent attachment in a nanostructure. Through the dual self-catalysis including intramolecular coreaction between TAEA and Au NCs, and intramolecular coreaction acceleration from Pd@CuO to TAEA, the Au NCs-TAEA-Pd@CuO achieved excellent ECL performance so that the detection limit of the immunosensor for measuring CEA antigen was down to 16 fg/mL in the absence of any additional signal amplification assay. Moreover, the method for preparing ECL nanostructure-based metal NCs should be devoted to the development of highly efficient ECL signal label, outlining a significant scheme toward biological testing and clinical diagnosis.