Lysosomes with a single-layered membrane structure are mainly involved in the scavenging of foreign substances and play an important role in maintaining normal physiological functions of living cells. In this work, near-neutrally charged fluorescent carbon dots (CDs) were prepared with lipophilicity through a facile one-pot hydrothermal carbonization of chloranil and triethylenetetramine at 160 °C for 3 h. The as-obtained CDs are proved to have good photostability, low cost, and excellent biocompatibility. Importantly, the as-prepared CDs with high quantum yield of 30.8% show excitation-dependent emission with great stability, and thus, they can be well used for the long-term target imaging of lysosomes in living cells without further modification. Meanwhile, the CDs can quickly enter into the lysosomes within 30 min, and the green fluorescence (FL) of CDs reaches the plateau when incubated for 60 min. By comparing the fluorescent intensity, the information about distribution and amount of lysosomes in different cells can be obtained. The proposed CD-based strategy demonstrates great promise for label-free target imaging of lysosomes in living cells. Graphical abstract The near-neutral carbon dots (CDs) with lipophilicity are used as label-free fluorescent nanoprobes for the long-term imaging of lysosomes in living cells.

中文翻译：

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用于活细胞溶酶体靶向成像的无标记氯和氮掺杂荧光碳点

具有单层膜结构的溶酶体主要参与外来物质的清除，对维持活细胞的正常生理功能起着重要作用。在这项工作中，通过氯苯醌和三亚乙基四胺在 160°C 下轻松一锅水热碳化 3 小时，制备了具有亲油性的近中性电荷荧光碳点 (CD)。所获得的CDs被证明具有良好的光稳定性、低成本和优异的生物相容性。重要的是，所制备的 CDs 具有 30.8% 的高量子产率，显示出具有很高稳定性的激发依赖性发射，因此，它们可以很好地用于活细胞中溶酶体的长期目标成像，而无需进一步修改。同时，CDs可以在30分钟内快速进入溶酶体，CDs 的绿色荧光 (FL) 在孵育 60 分钟后达到平台期。通过比较荧光强度，可以获得不同细胞中溶酶体的分布和数量信息。提议的基于 CD 的策略显示了对活细胞中溶酶体的无标记目标成像的巨大希望。图形摘要 具有亲脂性的近中性碳点 (CD) 用作无标记荧光纳米探针，用于活细胞中溶酶体的长期成像。