Electrochemiluminescence immunosensing strategy based on the use of Au@Ag nanorods as a peroxidase mimic and NH4CoPO4 as a supercapacitive supporter: Application to the determination of carcinoembryonic antigen

Abstract

The luminol-H 2 O 2 system is widely applied in electrochemiluminescence (ECL) assays but has limited stability. We are presenting an alternative immunosensing strategy by making use of Au@Ag nanorods that mimic the enzyme peroxidase. It also makes use of the supercapacitive supporter NH 4 CoPO 4 as a supporter substrate that facilitates ion movement due to its many nanogaps between the assembled nanoplates. It also plays a vital role for stabilizing the ECL signal of luminol. The immunosensor was constructed by first placing a chitosan film containing NH 4 CoPO 4 , Au@Ag and luminol on a glassy carbon electrode (GCE), and the immobilizing anti-CEA on its surface. ECL is generated via electrochemical reaction of luminol on the surface of the Au@Ag-luminol film in the presence of H 2 O 2 . The assay was evaluated with respect to effects of pH value, time and temperature of incubation, specificity, reproducibility, and stability in a lab setting. A linear relationship between ECL intensity and CEA concentration is found for the 0.1 pg·mL −1 to 380 ng·mL −1 range, and the lower detection limit is as low as 30 fg·mL −1 . In our perception, this immunoassay has a large scope in that numerous other immunoassays will become feasible by using other antibodies and, possibly, aptamers.

Enzyme Mimic Nanomaterials and Their Biomedical Applications

“…Their work holds great potential in the portable and quantitative detection of various targets. Other than Au@Pt bimetallic nanoparticles, Au@Ag, [41] Au@Pd [42] and Pd@Pt [43] nanoparticles have also been reported to have the enzymatic activity of peroxidase. Along with the rapid development of nanoparticle synthesis, the catalytic mechanism of different metal nanoparticles has been revealed with the help of theoretical simulation.…”

Trends and Advances in Electrochemiluminescence Nanobiosensors

“…In the presence of H 2 O 2 , ECL signal is generated when electrochemical reaction of luminol occurred on the surface of the Au@Ag-luminol film. The nanobiosensor was found to have a detection range of 0.1 pg mL −1 to 380 ng mL −1 , with a low detection limit of 30 fg mL −1 [ 78 ].…”

“…Reprinted from Ref. [ 78 ] with permission from Springer; ( C ) ECL nanobiosensor with nanocomposite of nanoFe 3 O 4 @GO. Reprinted from Ref.…”

Recent Advances in Graphitic Carbon Nitride-Based Chemiluminescence, Cataluminescence and Electrochemiluminescence

“…Therefore, ECL has been widely used in various sensors or probes for metal ions, anions, explosives, toxic food additives, biomolecules, and so on. Nanomaterials with smaller sizes, diversity shapes, specific structures and unique properties have played an increasingly important role in the development of ECL sensors [112][113][114][115]. In the recent years, g-C 3 N 4 has been extensively used in ECL-sensing systems due to the excellent electroconductive and catalytic characteristics and enormous specific surface area for the immobilization of various kinds of molecules; S 2 O 8 2-is the most widely used as the co-reactant to react with g-C 3 N 4 to emit light.…”