National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, PR China.
College of Chemical Engineering, Sichuan University, Chengdu, 610065, PR China.
Biosens Bioelectron. 2022 Mar 15;200:113928. doi: 10.1016/j.bios.2021.113928. Epub 2021 Dec 29.
Fluorescent probes enabling precisely labeling lipid droplets (LDs) in complex systems are highly desirable in life science for studying LDs-related physiological processes and metabolic diseases. However, most of the current LDs fluorophores fail to achieve rapid wash-free LDs labeling, especially in vivo labeling due to their strong hydrophobicity and poor water solubility. We report here one-step synthesis of highly efficient carbon dots (CDs) that feature robust solvatochromic emission, high quantum yield (QY) up to 76.35% in oil, good water solubility and lipophilicity, thus allowing to stain LDs in a bright and selective manner. Detailed characterizations reveal the presence of a well-defined molecule, 2-dimethylamino-5-fluorobenzimidazole in a large amount in CDs. Its D-π-A structure and dimethylamino-induced spatial torsion configuration and extended π-electron conjugation account for solvatochromic emission with high QY. Notably, the CDs can image LDs with many advanced merits (high brightness, ultrafast staining within 10 s, wash-free, excellent LDs specificity, good biocompatibility) and have been successfully applied to monitor cellular LDs dynamics. Moreover, the CDs for the first time allow in situ labeling of LDs and epidermal cell membranes simultaneously in live zebrafish. This work expands the diversity for optical properties and applications of CDs, facilitating the design of new LDs-targeting CDs.
荧光探针能够精确标记复杂体系中的脂滴（LDs），在生命科学中对于研究 LDs 相关的生理过程和代谢疾病非常重要。然而，由于大多数现有的 LDs 荧光探针具有较强的疏水性和较差的水溶性，因此它们往往无法实现快速、无清洗的 LDs 标记，尤其是在体内标记时。在这里，我们报告了一种一步法合成高效碳点（CDs）的方法，这种碳点具有强溶剂变色发射、高达 76.35%的油相量子产率（QY）、良好的水溶性和亲脂性，因此能够以明亮和选择性的方式对 LDs 进行染色。详细的表征揭示了 CDs 中存在大量结构明确的分子，即 2-二甲基氨基-5-氟苯并咪唑。其 D-π-A 结构和二甲氨基诱导的空间扭转构象以及扩展的π电子共轭解释了其具有高 QY 的溶剂变色发射。值得注意的是，这些碳点具有许多先进的优点（高亮度、在 10 秒内超快染色、无需清洗、出色的 LDs 特异性、良好的生物相容性），可用于监测细胞 LDs 的动态。此外，这些碳点还首次允许在活斑马鱼中同时对 LDs 和表皮细胞膜进行原位标记。这项工作扩展了 CDs 的光学性质和应用多样性，为设计新的靶向 LDs 的 CDs 提供了便利。
