Real-time monitoring and multicolor visual analysis of hydrogen peroxide based on antenna effect-induced dual signal amplification strategy

Dual-emission fluorescence (FL) sensing platform could not only facilitate sensitive visual sensing, but also increase detection accuracy through the change of the FL response and FL color. Herein, a novel ratiometric FL sensing platform was fabricated using the dual-ligand-functionalized dual-emission Eu(III) nanomaterial (i.e., Eu-CDs) based on antenna effect-induced dual signal amplification strategy. In the as-prepared nanomaterial, 2-thenoyltrifluoro-acetone was used as the first ligand to sensitize the FL characteristic emission of Eu(III). Interestingly, the use of carbon dots as the second ligand for Eu(III) could not only further enhance the FL emission of Eu(III), but also serve as a reference signal to achieve the ratiometric FL signals for the detection of hydrogen peroxide. The detection mechanism was that the S elements in the thiophene unit could be turned into sulfone groups by oxidation with hydrogen peroxide, which changed the coordination environment of Eu(III), leading to the decrease in FL intensity at 616 nm. Based on the ratiometric FL signals, we realized the real-time monitoring and multicolor visual analysis of hydrogen peroxide with a detection limit of 1.88 μM. The extraordinary detection capability of hydrogen peroxide achieved the distinction of normal cells from cancer cells and the highly selective determination of serum glucose as the model target in hydrogen peroxide-involved enzymatic reaction. This work not only provided a novel path for the fabrication of high-performance ratiometric FL sensing platform by ligand-functionalized dual-emission Eu(III)-based nanomaterial, but also showed the potential feasibility for rational design of the FL sensing platform.