Electrochemical stripping chemiluminescence coupled with recycling amplification strategy for sensitive detection of carcinoembryonic antigen

Abstract

As a new generation of electrochemiluminescence (ECL) technology, the electrochemical stripping chemiluminescence (ESCL), which combines the advantages of chemiluminescence and stripping voltammetry, has attracted increasing attention in the biosensor field. Here, Ag nanoclusters (NCs) were prepared using DNA double strands as a template and explored to construct an ESCL aptamer sensor (aptasensor) for the detection of a carcinoembryonic antigen (CEA). During the detection process, Ag NCs and the Ag+ cations stripped out from Ag NCs were found to respectively catalyze the electrochemical reduction and oxidation of H2O2, accelerating the decomposition of H2O2 to generate reactive oxygen species (ROSs) and thus effectively enhancing the ECL intensity of luminol. Coupled with the exonuclease I-assisted recycling amplification technology, the developed ESCL aptasensor enabled the sensitive detection of CEA, exhibiting a broad linear response from 100 ag/mL to 10 ng/mL with a low detection limit of 38.86 ag/mL (S/N = 3). In addition, the aptasensor showed good performance in the determination of CEA in human serum with a relative standard deviation (RSD) below 5 %. This work provides an effective method for constructing simple, fast, and sensitive biosensors.