A sandwich electrochemiluminescent assay for determination of concanavalin A with triple signal amplification based on MoS₂NF@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-H₂O₂ 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 (MoS₂NF@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 H₂O₂ 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.