State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
College of Physics, Jilin University, Changchun 130012, P. R. China.
ACS Sens. 2023 May 26;8(5):1939-1949. doi: 10.1021/acssensors.2c02678. Epub 2023 May 2.
As a dynamic and multifunctional organelle, lipid droplets (LDs) are essential in maintaining lipid balance and transducing biological signals. LD accumulation and catabolism are closely associated with energy metabolism and cell signaling. In order to easily trace LDs in living cells, a novel carbonized polymer dot (CPD)-based fluorescent nanoprobe is reported to serve the needs of LD-targeting imaging. This probe exhibits the advantages of excellent biocompatibility, simple preparation, good lipophilicity, and high compatibility with commercial dyes. Transient absorption spectroscopy was employed to discuss the luminescence mechanism of CPDs, and the results indicate that the excellent fluorescence property and the environment-responsive feature of our CPDs are derived from the intramolecular charge transfer (ICT) characteristics and the D-π-A structure that possibly formed in CPD. This nanoprobe is available for one-photon fluorescence (OPF) and two-photon fluorescence (TPF) imaging and is also practicable for staining LDs in living/fixed cells and lipids in tissue sections. The staining process is completed within several seconds, with no washing step. The intracellular LDs involving the intranuclear LDs (nLDs) can be selectively lit up. This probe is feasible for visualizing dynamic interactions among LDs, which suggests its great potential in revealing the secret of LD metabolism. The TPF spectra were analyzed to determine surrounding microenvironment according to the polarity-responsive feature of our CPDs. This work expands the applications of CPDs in biological imaging, helps design new LD-selective fluorescent probes, and has implications for studying LD-related metabolism and diseases.
作为一个动态且多功能的细胞器，脂滴（LDs）在维持脂质平衡和传递生物信号方面至关重要。LD 的积累和分解与能量代谢和细胞信号密切相关。为了方便在活细胞中追踪 LD，报道了一种新型基于碳化聚合物点（CPD）的荧光纳米探针，以满足 LD 靶向成像的需求。该探针具有优异的生物相容性、简单的制备、良好的亲脂性以及与商业染料高度兼容的优点。瞬态吸收光谱用于讨论 CPD 的发光机制，结果表明，CPD 的优异荧光性能和环境响应特性源于分子内电荷转移（ICT）特性和可能在 CPD 中形成的 D-π-A 结构。该纳米探针可用于单光子荧光（OPF）和双光子荧光（TPF）成像，也可用于活/固定细胞中 LD 和组织切片中脂质的染色。染色过程在几秒钟内完成，无需洗涤步骤。可以选择性地点亮涉及核内 LD（nLDs）的细胞内 LD。该探针可用于可视化 LD 之间的动态相互作用，这表明其在揭示 LD 代谢秘密方面具有很大的潜力。根据 CPD 的极性响应特性，对 TPF 光谱进行了分析，以确定周围的微环境。这项工作扩展了 CPD 在生物成像中的应用，有助于设计新的 LD 选择性荧光探针，并对研究 LD 相关代谢和疾病具有重要意义。
