Micelle-Assisted Confined Coordination Spaces for Benzimidazole: Enhanced Electrochemiluminescence for Nitrite Determination.

Selective and sensitive detection of nitrite has important medical and biological implications. In the present work, to obtain an enhanced electrochemiluminescence (ECL) determination of nitrite, a novel nano-ECL emitter CoBIM/cetyltrimethylammonium bromide (CTAB) was prepared via a micelle-assisted, energy-saving, and ecofriendly method based on benzimidazole (BIM) and CTAB. Unlike conventional micelle assistance, the deprotonated BIM (BIM-) preferential placement was in the palisade layer of cationic CTAB-based micelles. Enriching the original CTAB micelle with BIM- disrupted its stability and resulted in the formation of considerably smaller BIM/CTAB-based micelles, providing a confined coordination environment for BIM- and Co2+. As a result, the growth of CoBIM/CTAB was also limited. Owing to the unusual nitration reaction between BIM and nitrite, the prepared CoBIM/CTAB was successfully applied as a novel ECL probe for the detection of nitrite with a wide linear range of 1-1500 µM and a low detection limit of 0.67 µM. This work also provides a promising ECL platform for ultrasensitive monitoring of nitrite and it was applied with sausages and pickled vegetables.

l-Cysteine-Tuned the Hierarchical Structure Based on Benzimidazole: Synthesis, Characterization, and Application in Ratiometric Electrochemiluminescence Immunoassay.

Efficient and robust electrochemiluminescence (ECL) emitters are crucial for enhancing the ECL immunosensor sensitivity. This study introduces a novel ECL emitter, CoBIM/Cys, featuring a hierarchical core-shell structure. The core of the structure is created through the swift coordination between the sulfhydryl and carboxyl groups of l-cysteine (l-Cys) and cobalt ions (Co2+), while the shell is constructed by sequentially coordinating benzimidazole (BIM) with Co2+. This design yields a greater specific surface area and a more intricate porous structure compared to CoBIM, markedly enhancing mass transfer and luminophore accessibility. Moreover, the l-Cys and Co2+ core introduces Co-S and Co-O catalytic sites, which improve the catalytic decomposition of H2O2, leading to an increased production of hydroperoxyl radicals (OOH•). This mechanism substantially amplifies the ECL performance. Leveraging the competitive interaction between isoluminol and BIM for OOH• during ECL emission, we developed a ratiometric immunosensor for cardiac troponin I (cTnI) detection. This immunosensor demonstrates a remarkably broad detection range (1 pg mL-1 to 10 ng mL-1), a low detection limit (0.4 pg mL-1), and exceptional reproducibility and specificity.