Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
Department of Pharmacy, Taihe Hospital, Hubei University of Medicine, Shiyan, 44200, Hubei, China.
Mikrochim Acta. 2022 May 18;189(6):223. doi: 10.1007/s00604-022-05318-1.
Nine kinds of carbon dots (CDs) were synthesized by using fruits with different varieties as carbon sources; meanwhile, the fluorescence characteristics, quantum yield, and response ability to different metal ions and free radicals were systematically studied. These CDs showed similar excitation and emission spectral ranges (λ ≈ 345 nm, λ ≈ 435 nm), but very different fluorescence quantum yield (QY), in which orange and cantaloupe CDs have the highest QY around 0.25 and green plum CDs showed the lowest quantum yield around 0.1. Interestingly, the fluorescence of all of these CDs can be significantly quenched by hydroxyl radical (•OH) and iron ion (Fe); however, these CDs showed very different response characteristics to other metal ions (e.g., Co, Ni, Cu, Ce, Mn, Ag, and Fe). Through in-depth analysis, we found some interesting patterns of the influence of carbon sources on the fluorescence characteristics of CDs. Finally, by using white pitaya CDs as fluorescence probe, we realized sensing of Fe and •OH with limits of detection (LOD) of 19.4 μM and 0.7 μM, respectively. Moreover, the CDs were also capable for sensitive detection in immune cells and even in zebrafishes. Our work can provide valuable guidance for the rational design of functional CDs for biological applications.
合成了九种碳点（CDs），它们的碳源分别来自不同品种的水果；同时，系统研究了它们的荧光特性、量子产率以及对不同金属离子和自由基的响应能力。这些 CDs 具有相似的激发和发射光谱范围（λ≈345nm，λ≈435nm），但荧光量子产率（QY）却有很大的不同，其中橙色和哈密瓜 CDs 的量子产率最高，约为 0.25，而绿色李 CD 的量子产率最低，约为 0.1。有趣的是，所有这些 CDs 的荧光都可以被羟基自由基（•OH）和铁离子（Fe）显著猝灭；然而，这些 CDs 对其他金属离子（如 Co、Ni、Cu、Ce、Mn、Ag 和 Fe）的响应特性却非常不同。通过深入分析，我们发现了一些有趣的模式，即碳源对 CDs 荧光特性的影响。最后，我们使用火龙果 CDs 作为荧光探针，实现了对 Fe 和 •OH 的检测，其检测限（LOD）分别为 19.4μM 和 0.7μM。此外，该 CDs 还能够用于免疫细胞甚至斑马鱼中的灵敏检测。我们的工作为生物应用中功能性 CDs 的合理设计提供了有价值的指导。
