A Isophorone Zn(II) based metal-organic complex fluorescent sensor for monitoring H2O2 and application in real samples, cells, zebrafish and mice.

Hydrogen peroxide (H₂O₂) is not only widely used as a biomarker in organisms, but also can be used to effectively remove heavy metal ions, harmful bacteria, and refractory organic compounds in the water environment. Therefore, it is necessary to develop a sensing and visualization tool to monitor the levels of H2O2 in organism and water samples. A novel complex MP was successfully synthesized based on isophorone, which formed a fluorescent sensor (Zn2+-MP) with Zn2+ for swiftly and accurately detecting H2O2. Notably, the sensor exhibited rapid, remarkable selectivity, anti - interference ability, and multi - cycle reversibility through "turn-off-on" fluorescence for H2O2. Surprisingly, through Job's plot, FT-IR, ESI-HRMS, 1HNMR titration and theoretical calculations, the possible mechanism by which MP formed a complex with Zn2+ to achieve the detection of H2O2 has been deduced, contained the Zn2+-MP sensor itself exhibited low fluorescence, however when H2O2 was added, H2O2 competitively captured the MP complex in Zn2+-MP sensor, releasing MP to enhance fluorescence. Besides, the ability of Zn2+-MP sensor to detect actual water samples (including medicine honeysuckle, soil samples, green tea extract solutions and so on) were tested. Meanwhile, the Zn2+-MP sensor has been successfully achieved visual monitoring in mice, zebrafish and cells. To sum up, the Zn2+-MP sensor held great promise as a highly versatile approach for the rapid and reversible detection of H₂O₂.