A novel chemiluminescence biosensor based on dual aptamers bound nanoparticles with multi-site signal amplification for sensitive detection of carcinoembryonic antigen

Abstract

The establishment of stable and simple detection methods for cancer markers is very necessary for the treatment of cancer. In this study, based on the fact that carcinoembryonic antigen (CEA) has dual recognized aptamers, the aptamer1 (Apt1) is connected with magnetic beads (MBs) to form MBs-Apt1. Meanwhile, using the histidine (His) as the medium, nickel hexacyanoferrate nanoparticles (Ni NPs) as the catalyst, the Ni NPs-His-aptamer2 (Apt2) has also been prepared. In the presence of CEA, the MBs-Apt1 combined with Apt2-His-Ni NPs can specifically recognize CEA and form MBs-Apt1/CEA/Apt2-His-Ni NPs classical “sandwich” structure with signal cascade amplification. Remarkably, the cubic crystal structure of Ni NPs allows it to have multiple catalytically active sites, and plentiful His with − COOH can quickly bind to amino-modified Apt2 and chelate Ni NPs to form Apt2-His-Ni NPs. In another strategy, specific recognition of streptavidin (SA)-modified gold nanoparticles (Au NPs) using streptavidin aptamer (SAA), similarly established the MBs-Apt1/CEA/Apt2-SAA-SA@Au NPs classical “sandwich” structure with signal cascade amplification of luminol. The detection limits of the two methods were 0.092 pg/mL and 0.122 pg/mL, respectively. As predicted, protein biomarkers with concentrations as low as pg/mL can be detected in a very small amount of serum. And thus, there will be a bright future in the detection of CEA and other tumor markers in the early diagnosis of cancer.