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.

Automated summary

This study developed novel carbon quantum dots that can detect and quantify selenite, with good water solubility and biocompatibility, and imaging capabilities in cells. Therefore, these carbon quantum dots have great potential for detecting and treating selenite-associated diseases.