Ultrasensitive and selective fluorescence recognition of selenite by o-phenylenediamine functionalized carbon quantum dots

Selenite (SeO32−), as the most toxic form of selenium in water, is a great threat to water quality and human health, which also has been closely associated with various physiological and pathological processes. The sensitive detection and quantification of SeO32− are imperative for the early diagnosis and prevention of selenite-associated disease. Herein, we constructed novel o-phenylenediamine functionalized carbon quantum dots (OPD-CQDs) by a one-step hydrothermal method. The OPD-CQDs exhibited good water solubility, high quantum yield, strong photostability, excellent biocompatibility and cell imaging capabilities, and also displayed high selectivity and sensitivity to SeO32− with an excellent linear relationship and a low limit of detection (86 nM). Moreover, the OPD-CQDs were successfully employed for the quantitative determination of SeO32− in tap water and human serum with high accuracy and recovery rate. In particular, the designed OPD-CQDs were successfully applied for intracellular SeO32− detection with excellent biocompatibility and cellular imaging capability. The present research demonstrated that OPD-CQDs provided a novel approach for imaging and detecting SeO32− in live cells and in vivo. Based on these excellent properties and comprehensive applications, OPD-CQDs illustrated great potential to offer a scientific and effective method for SeO32− detection in complex environments and clinical early diagnosis of SeO32− related diseases.