Fe-Co-Co prussian blue analogues as a novel co-reaction accelerator for ultrasensitive electrochemiluminescent biosensor construction.

• Fe-Co-Co PBAs as a novel co-reaction accelerator of the C-g-C 3 N 4 /S 2 O 8 2− ECL system to amplify the ECL signal. • The proposed method holds a new perspective of PBAs nanomaterials in biosensing. • The synthesis method of core-shell Fe-Co-Co PBAs@C-g-C 3 N 4 is facile and green. • The ECL biosensor achieved a sensitive and selective detection of MTX. An ultrasensitive electrochemiluminescence (ECL) biosensor was constructed by using Fe y Co 3-y [Co(CN) 6 ] 2 prussian blue analogues (Fe-Co-Co PBAs) as a novel electrochemically regenerable co-reaction accelerator for methotrexate (MTX) detection. In this work, we synthesized the core-shell Fe-Co-Co PBAs@C-g-C 3 N 4 tags with luminophores and co-reaction accelerators via a facile and green method. To the best of our knowledge, it is the first time that Fe-Co-Co PBAs was used as an efficient co-reaction accelerator of the carboxylated graphene-like carbon nitride /peroxydisulfate (C-g-C 3 N 4 /S 2 O 8 2−) ECL system for signal amplification. In view of the prominent quenching effect of MTX on the ECL response of the C-g-C 3 N 4 , the proposed ECL biosensor exhibited high sensitivity to quantify the concentration of MTX from 5 pM to 10 μM with a detection limit of 1.1 pM. Simultaneously, the biosensor has also been successfully applied to MTX detection in human serum and urine samples with reasonable recoveries. Hence, the proposed method holds a new perspective of PBAs nanomaterials in biosensing and provides a potential analysis method for the rapid detection of MTX in biological systems. [ABSTRACT FROM AUTHOR]