Au modified spindle-shaped cerium phosphate as an efficient co-reaction accelerator to amplify electrochemiluminescence signal of carbon quantum dots for ultrasensitive analysis of aflatoxin B1

• CePO 4 @Au was introduced into the ECL immunosensor for the first time, which significantly improved the electrochemiluminescence intensity of the NHCDs-H 2 O 2 system. • CePO 4 @Au can promote the decomposition of H 2 O 2 to produce O 2 •− , the repeated conversion of Ce 4+ and Ce 3+ has high electrocatalysis activity, which can facilitate the production of O 2 •− . • BaTiO 3 @Ag was used as a carrier to accurately capture NHCDs and anchor antibodies to provide a stable ECL signal. • The established ECL immunosensor exhibited low detection limit of 9.55 fg/mL for AFB1. In various detection methods of aflatoxin B1 (AFB1), false positives and false negatives are common due to the low sensitivity, expensive equipment or improper pretreatment during operation. Here, a sandwich electrochemiluminescence (ECL) immunosensor armed with a synergistic co-reaction acceleration strategy was employed for the ultra-sensitive detection of AFB1. Benefiting from the catalytic properties of Ce 3+ /Ce 4+ redox pairs, cerium phosphate@gold (CePO 4 @Au), for the first time, was introduced into the immunosensor as a new type of co-reaction accelerator, and it significantly improved the ECL intensity of the nitrogen doped hydrazide conjugated carbon dots (NHCDs)-H 2 O 2 system. CePO 4 @Au has the ability to promote the decomposition of H 2 O 2 and accelerate the formation of O 2 •− . The more of O 2 •− reacts with NHCDs to produce a stronger and more robust ECL signal response. Furthermore, the spindle-shaped sensing interface formed by oxidation cerium and phosphate has a high loading area and good biocompatibility, and the modification of Au nanoparticles further achieves the stable binding of the capture antibody. Striving for further improvement, Ag modifies Barium titanate (BaTiO 3 ), as the signal carrier with amplification ability, loads with a large number of anodic luminescent carbon quantum dots, were adopted as detection markers for the construction of sandwich ECL biosensors. The co-reaction amplification system achieves high precision quantitative detection of AFB1 in the linear range of 0.01 pg/mL–100 ng/mL, and the detection limit is 9.55 fg/mL. In addition, the constructed biosensor also showed good stability, reproducibility and specificity, with a promising application prospect.