Label-free differential chemiluminescent immunosensor based on magnetic nanoparticles CuFe2O4@ABEI-GNPs with dual catalytic sites

Cancer has become one of the main causes of death globally. The level of tumor markers in serum is correlated with the occurrence of cancer. Carcinoembryonic antigen (CEA) is the most commonly utilized tumor marker for cancer detection. Recently, various analytical technologies have been reported to detect biomarkers. However, developing a simple, sensitive, and noninvasive approach for CEA detection remains challenging in cancer diagnosis. Consequently, there is an urgent need for researchers to carry out innovative approaches for CEA detection. In this work, copper ferrite nanoparticles (CuFe2O4 NPs) with excellent dispersity and fascinating magnetism have been successfully synthesized. To get CuFe2O4@ABEI-GNPs, ABEI-gold NPs (ABEI-GNPs) were generated on the surface of CuFe2O4 NPs by using N-(4-Aminobutyl)-N-ethylisoluminol (ABEI) as a mild reduction reagent to reduce chloroauric acid tetrahydrate (HAuCl4·4H2O). The CuFe2O4@ABEI-GNPs exhibited a superior chemiluminescence (CL) performance compared with CuFe2O4@ABEI NPs, which was attributed to the synergistic catalysis effects of CuFe2O4 NPs and GNPs. Interestingly, two unique CL emission peaks were observed in the kinetic curve of CuFe2O4@ABEI-GNPs. Furthermore, it was found that the kinetic curve could be regulated by the pH of hydrogen peroxide (H2O2) and a possible CL mechanism was proposed. Owing to the favorable CL properties of CuFe2O4@ABEI-GNPs, a label-free differential immunosensor was fabricated for CEA monitoring using the intensity difference between CL-1 and CL-2. The developed immunosensor exhibited a wide linear range from 0.1 to 5000 pg/mL, and a low detection limit of 0.05 pg/mL. The immunosensor was capable of determining CEA in real samples with simple operation, high accuracy, and good sensitivity. This study introduces a novel approach for developing CL functionalized materials, which have broad application potential in bioassays. The proposed differential method could serve as a novel tool for determining CEA in the diagnosis of clinical cancer. [Display omitted] •The proposed nanomaterial possessed good dispersity and magnetic property.•CuFe2O4@ABEI-GNPs with dual catalytic centers exhibited superior CL performance.•The possible CL mechanism of two CL peaks in one kinetic curve was proposed.•A label-free differential CL immunosensor for CEA detection was fabricated.