A sandwich electrochemiluminescent assay for determination of concanavalin A with triple signal amplification based on MoSNF@MWCNTs modified electrode and Zn-MOF encapsulated luminol.

An ultrasensitive sandwich electrochemiluminescence (ECL) biosensor was designed for determination of concanavalin A (ConA) through the specific carbohydrate-ConA interactions. Three-dimensional porous metal-organic framework (Zn-MOF) was synthesized, which loaded a large amount of luminescent reagents as luminol by encapsulating into its pores to form Zn-MOF@luminol complex. Interestingly, Zn-MOF also acted as the coreactant accelerator in the luminol-HO ECL system. This Zn-MOF@luminol complex was used as the signal probe to achieve a super strong and stable ECL signal. In addition, three-dimensional hierarchical molybdenum disulfide nanoflower and multiwalled carbon nanotubes complex (MoSNF@MWCNTs) with peroxidase-mimicking enzyme property were used as a substrate to modify the glassy carbon electrode to further enhance the ECL signal of luminol by promoting decomposition of HO into reactive oxygen species (ROSs). In addition to the horseradish peroxidase (HRP) catalysis effect on the luminol ECL signal, a triple amplified ConA sandwich ECL sensor with high sensitivity sensor was constructed. The linear range for ConA detection was from 0.5 pg/mL to 100 ng/mL with a detection limit of 0.3 pg/mL (S/N = 3). The recovery test for ConA in human serum samples was performed with satisfactory results. Graphical abstract.