School of Chemistry and Chemical Engineering, Anhui University, 111 Jiulong Road, Hefei, 230601, P. R. China.
School of Materials Science and Engineering, Anhui University, 111 Jiulong Road, Hefei, 23060, P. R. China.
Adv Mater. 2023 May;35(21):e2210776. doi: 10.1002/adma.202210776. Epub 2023 Apr 2.
It is significant to monitor the different RNA granules dynamics and phase separation process inside cells under various stresses, for example, oxidative stress. The current small-molecule RNA probes work well only in fixed cells and usually encounter problems such as insufficient stability and biocompatibility, and thus a specific RNA-targeting fluorescent nanoprobe that can be used in the living cells is urgently desired. Here, the de novo design and microwave-assisted synthesis of a novel RNA-targeting, red-emissive carbon dots (named as M-CDs) are reported by choosing neutral red and levofloxacin as precursors. The as-synthesized M-CDs is water-soluble with a high fluorescence quantum yield of 22.83% and can selectively bind to RNA resulting in an enhanced red fluorescence. More interestingly, such an RNA-targeting, red-emissive M-CDs can be fast internalized into cells within 5 s and thus used for real-time imaging the dynamic process of intracellular stress granules under oxidative stress, revealing some characteristics of granules that have not been identified by previously reported RNA and protein biomarkers. This research paves a new pathway for visualizing bulk RNA dynamics and studying phase-separation behaviors in living cells by rational design of the fluorescent carbon dots in terms of structure and functionality.
在各种应激条件下，例如氧化应激，监测细胞内不同 RNA 颗粒的动力学和相分离过程具有重要意义。目前的小分子 RNA 探针仅在固定细胞中效果良好，但通常会遇到稳定性和生物相容性不足等问题，因此迫切需要一种可用于活细胞的特定 RNA 靶向荧光纳米探针。在此，通过选择中性红和左氧氟沙星作为前体，报道了一种新型 RNA 靶向、红光发射碳点（命名为 M-CDs）的从头设计和微波辅助合成。所合成的 M-CDs 具有水溶性，荧光量子产率高达 22.83%，可以选择性地与 RNA 结合，从而增强红色荧光。更有趣的是，这种 RNA 靶向、红光发射的 M-CDs 可以在 5 秒内快速内吞到细胞内，从而用于实时成像氧化应激下细胞内应激颗粒的动态过程，揭示了一些以前报道的 RNA 和蛋白质生物标志物未识别的颗粒特征。这项研究为通过荧光碳点的结构和功能的合理设计来可视化大量 RNA 动力学和研究活细胞中的相分离行为开辟了一条新途径。
