A ratiometric electrochemiluminescent/electrochemical strategy based on novel designed BPYHBF nanorod and Fc-MOF with tungsten for ultrasensitive AFB1 detection

Fluorescent dyes have been considered as one of the most potential candidates for electrochemiluminescence (ECL) reagent due to the excellent photophysical and electrochemical characteristics in recent years. However, the severe self-absorption effect caused by narrow stokes shift inevitably limits its application for ECL. In this work, a new type of ECL emitter, 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene derivative, a BF2 complex of hydrazine-schiff base linked bispyrrole, namely BPYHBF, was prepared and employed as a probe to label the competitor of target in the immunosensor, which could emit powerful ECL signal with tri-n-propylamine. The structure and ECL property of BPYHBF were investigated. Additionally, multi-walled carbon nanotube/ ferrocenecarboxaldehyde-metal organic framework (MWCNTs/Fc-MOF) as sensing substrate for Ab1 incubation was synthesized, where the large specific surface area and stable internal reference electrochemical signals improved the sensitivity and reliability of the sensor by self-correction. Herein, a novel ratiometric competitive immunosensor based on the ECLBPYHBF/DPVFc was prepared for ultrasensitive detection of aflatoxin B1 (AFB1). The ratio value is linear in the range from 10 fg/mL to 100 ng/mL, and the detection limit is 5.39 fg/mL. The prepared sensor exhibited excellent sensitivity, accuracy and reproducibility, and achieved satisfactory detection towards AFB1 in actual samples, this demonstrates a promising application in biomolecules detection.

Automated summary

Fluorescent dyes are potential candidates for electrochemiluminescence reagents, but their application is limited due to self-absorption effects. A novel ECL emitter BPYHBF was developed for labeling competitors in immunosensors, along with a sensing substrate MWCNTs/Fc-MOF to improve sensor sensitivity and reliability. The ratiometric competitive immunosensor was successfully prepared for ultrasensitive detection of AFB1, with excellent sensitivity, accuracy, and reproducibility demonstrated in actual samples.