Preparation and application of high-brightness red carbon quantum dots for pH and oxidized L-glutathione dual response

• Published in: Analyst (London) 2023-05, Vol.148 (10), p.2375-2386
• Main Authors: Du, Yuwei, Cao, Lei, Li, Xinlu, Zhu, Tongtong, Yan, Ruhong, Dong, Wen-Fei, Li, Li
• Format: Article
• Language: English
• Subjects: Animals; Brightness; Bromine; Carbon; Carbon - chemistry; Carbon dots; Emission; Fluorescent Dyes - chemistry; Fluorescent indicators; Glutathione; Glutathione Disulfide; Hydrogen-Ion Concentration; Lysosomes; Medical imaging; Nitrogen - chemistry; Protonation; Quantum dots; Quantum Dots - chemistry; Zebrafish
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/d3an00383c

Carbon dots (CDs) with red fluorescence emission are highly desirable for use in bioimaging and trace- substance detection, with potential applications in biotherapy, photothermal therapy, and tumor visualization. Most CDs emit green or blue fluorescence, thus limiting their applicability. We report a novel fluorescent detection platform based on high-brightness red fluorescence emission carbon dots (R-CDs) co-doped with nitrogen and bromine, which exhibit pH and oxidized L-glutathione (GSSG) dual-responsive characteristics. The absolute quantum yield of the R-CDs was as high as 11.93%. We discovered that the R-CDs were able to detect acidic pH in live cells and zebrafish owing to protonation and deprotonation. In addition, GSSG was detected over a broad linear range (8-200 μM) using the R-CDs with excitation-independent emission. Furthermore, cell imaging and bioimaging experiments demonstrated that the R-CDs were highly cytocompatible and could be used as fluorescent probes to target lysosomes and nucleolus. These studies highlight the promising prospects of R-CDs as biosensing tools for bioimaging and trace-substance detection applications.