Fenton-like reaction triggered chemical redox-cycling signal amplification for ultrasensitive fluorometric detection of H2O2 and glucose

• Published in: Analyst (London) Vol. 149; no. 2; pp. 546 - 552
• Main Authors: Sun, Lu, Lin-Ge, Chen, Hai-Bo Wang
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 15.01.2024
• Subjects: Amplification; Biosensors; Cascade chemical reactions; Copper; Cycles; Fluorescence; Glucose; Hydrogen peroxide; Hydroxyl radicals; Oxidation; Phenylenediamine; Photosensitivity
• ISSN: 0003-2654; 1364-5528; 1364-5528
• DOI: 10.1039/d3an01682j

An ultrasensitive fluorescent biosensor is reported for glucose detection based on a Fenton-like reaction triggered chemical redox-cycling signal amplification strategy. In this amplified strategy, Cu2+ oxidizes chemically o-phenylenediamine (OPD) to generate photosensitive 2,3-diaminophenazine (DAP) and Cu+/Cu0. On the one hand, the generated Cu0 catalyzes the oxidation of OPD. On the other hand, H2O2 reacts with Cu+ to produce hydroxyl radicals (·OH) and Cu2+ through a Cu+-mediated Fenton-like reaction. The generated ·OH and recycled Cu2+ ions take turns oxidizing OPD to produce more photoactive DAP, triggering a self-sustaining chemical redox-cycling reaction and a remarkable fluorescent enhancement. It is worth mentioning that the cascade reaction did not stop until OPD molecules were completely consumed. Benefiting from H2O2-triggered chemical redox-cycling signal amplification, the strategy was exploited for the development of an ultrasensitive fluorescent biosensor for glucose determination. Glucose content monitoring was realized with a linear range from 1 nM to 1 μM and a limit of detection of 0.3 nM. This study validates the practicability of the chemical redox-cycling signal amplification on the fluorescent bioanalysis of glucose in human serum samples. It is expected that the method offers new opportunities to develop ultrasensitive fluorescent analysis strategy.