Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, 781039 Guwahati, Assam, India.
ACS Appl Bio Mater. 2021 Oct 18;4(10):7605-7614. doi: 10.1021/acsabm.1c00867. Epub 2021 Sep 23.
Recently, multimodal detection of analytes through a single nanoprobe has become an eminent approach for researchers. Herein a fluorescent nanoprobe, functionalized-GQD (F-GQD), has been designed through edge functionalization of graphene quantum dots (GQDs) by 2,6-diaminopyridine molecules. The fluorescence of F-GQD is quite sensitive to medium pH, making it a suitable pH sensor within the pH range 2-6. Interestingly, F-GQD shows dual sensing of Pb and ClO by entirely different pathways; Pb exhibits fluorescence turn-on performance while ClO triggers turn-off fluorescence quenching. The fluorescence enhancement may originate from the Pb-induced aggregation of the nanodots. The limit of detection (LOD) was also impressive, 1.2 μM and 12.6 nM for Pb and ClO, respectively. The detailed mechanistic investigations reveal that both dynamic and static quenching effects operate together in the F-GQD-ClO system. The dynamic quenching was attributed to the energy migration from F-GQD to ClO through hydrogen bonding interaction (static quenching) between the amine group at the F-GQD surface and ClO. The F-GQD nanodot reveals excellent sensitivity toward the detection of ClO in real samples. Moreover, the F-GQDs also serve as multicolor fluorescent probes for cell imaging; the probe can easily penetrate the cell membrane and successfully detect intracellular ClO.
最近，通过单个纳米探针对分析物进行多模态检测已成为研究人员的一种重要方法。在此，通过 2,6-二氨基吡啶分子对石墨烯量子点（GQDs）的边缘功能化，设计了荧光纳米探针，功能化-GQD（F-GQD）。F-GQD 的荧光对介质 pH 非常敏感，使其成为 pH 2-6 范围内的合适 pH 传感器。有趣的是，F-GQD 通过完全不同的途径对 Pb 和 ClO 表现出双重传感；Pb 表现出荧光开启性能，而 ClO 则触发荧光猝灭。荧光增强可能源于纳米点的 Pb 诱导聚集。检测限（LOD）也令人印象深刻，分别为 1.2 μM 和 12.6 nM 用于 Pb 和 ClO。详细的机制研究表明，在 F-GQD-ClO 体系中，动态和静态猝灭效应共同作用。动态猝灭归因于通过 F-GQD 表面的氨基与 ClO 之间的氢键相互作用（静态猝灭）从 F-GQD 到 ClO 的能量迁移。F-GQD 纳米点对 ClO 在实际样品中的检测具有优异的灵敏度。此外，F-GQDs 还可用作细胞成像的多色荧光探针；探针可以轻松穿透细胞膜并成功检测细胞内的 ClO。
