A Carbonate-Involved Amplification Strategy for Cathodic Electrochemiluminescence of Luminol Triggered by the Catalase-like CoO Nanorods

Abstract

The lumiol-O2 electrochemiluminescence (ECL) system constantly emits bright light at positive potential. Notably, compared with the anodic ECL signal of the luminol-O2 system, the great virtues of cathodic ECL are that it is simple and causes minor damage to biological samples. Unfortunately, little emphasis has been paid to cathodic ECL, owing to the low reaction efficacy between luminol and reactive oxygen species. The state-of-the-art work mainly focuses on improving the catalytic activity of the oxygen reduction reaction, which remains a significant challenge. In this work, a synergistic signal amplification pathway is established for luminol cathodic ECL. The synergistic effect is based on the decomposition of H2O2 by catalase-like (CAT-like) CoO nanorods (CoO NRs) and regeneration of H2O2 by a carbonate/bicarbonate buffer. Compared with Fe2O3 nanorod (Fe2O3 NR)- and NiO microsphere-modified glassy carbon electrodes (GCEs), the ECL intensity of the luminol-O2 system is nearly 50 times stronger when the potential ranged from 0 to −0.4 V on the CoO NR-modified GCE in a carbonate buffer solution. The CAT-like CoO NRs decompose the electroreduction product H2O2 into OH· and O2 · –, which further oxidize HCO3 – and CO3 2– to HCO3 · and CO3 · –. These radicals very effectively interact with luminol to form the luminol radical. More importantly, H2O2 can be regenerated when HCO3 · dimerizes to produce (CO2)2*, which provides a cyclic amplification of the cathodic ECL signal during the dimerization of HCO3 ·. This work inspires developing a new avenue to improve cathodic ECL and deeply understand the mechanism of a luminol cathodic ECL reaction.

Dual-Mechanism-Driven Ratiometric Electrochemiluminescent Biosensor for Methicillin-Resistant Staphylococcus aureus

“…Thus, MOF PCN 224 constructed by connecting Zr 6 -oxygen clusters with TCPP may serve as a promising option for developing a porphyrin-based ECL biosensor with cathodic emission. Luminol is a well-established organic ECL luminophore with remarkable luminous efficiency, which can emit an intensive signal during the anodic process. − Nonetheless, immobilization of luminol onto the electrode for fabricating biosensors remains a challenging task since it is an aqueous soluble small-molecular compound. Fortunately, the presence of an active amino group on the aromatic ring of the luminol molecule facilitates its conjugation with other nonsoluble materials for developing biosensors.…”

Renewable Electrochemiluminescence Biosensor Based on Eu-MOGs as a Highly Efficient Emitter and a DNAzyme-Mediated Dual-drive DNA Walker as a Signal Amplifier for Ultrasensitive Detection of miRNA-222

“…ECL molecular luminophors such as luminol, Ru­(bpy) 3 2+ , and their derivatives have been studied for a long time because of their merits in good stability and high ECL signals, but they are also suffering from poor biocompatibility and high cost. In recent years, nanomaterials (nanoclusters, quantum dots, inorganic and organic nanomaterials, etc.)…”

Wireless rotating bipolar electrochemiluminescence for enzymatic detection

“…However, in recent years, several authors reported the cathodic ECL emission in various conditions, 55,59,60 such as with catalytic nanomaterials, e.g. zinc oxide nanoparticle-modified Ni-foam, 61 carbonized polydopamine nanotubes, 62 catalase-like CoO nanorods, 63 acetylene black oxide, 64 two-dimensional NiM metal–organic framework (MOF, with M = Fe, Co, and Zn). 65 By adjusting iron single atom structures, the enhancement mechanism of luminol cathodic ECL was investigated and found to involve the production of massive reactive oxygen species for the generation of luminol radicals.…”