Specific Two-Photon Imaging of Live Cellular and Deep-Tissue Lipid Droplets by Lipophilic AIEgens at Ultralow Concentration
作者:Guangle Niu、Ruoyao Zhang、John P. C. Kwong、Jacky W. Y. Lam、Congping Chen、Jianguo Wang、Yuncong Chen、Xing Feng、Ryan T. K. Kwok、Herman H.-Y. Sung、Ian D. Williams、Mark R. J. Elsegood、Jianan Qu、Chao Ma、Kam Sing Wong、Xiaoqiang Yu、Ben Zhong Tang
DOI:10.1021/acs.chemmater.8b01943
日期:2018.7.24
Lipid droplets are highly associated with obesity, diabetes, inflammatory disorders, and cancer. A reliable two-photon dye for specific lipid droplets imaging in live cells and live tissues at ultralow concentration has rarely been reported. In this work, four new aggregation-induced emission luminogens (AIEgens) based on the naphthalene core were designed and synthesized for specific two-photon lipid droplet staining. The new molecules, namely, NAP AIEgens, exhibit large Stokes shift (>110 nm), high solid-state fluorescence quantum yield (up to 30%), good two-photon absorption cross section (45–100 GM at 860 nm), high biocompatibility, and good photostability. They could specifically stain lipid droplets at ultralow concentration (50 nM) in a short time of 15 min. Such ultralow concentration is the lowest value for lipid droplets staining in live cells reported so far. In vitro and ex vivo two-photon imaging of lipid droplets in live cells and live mice liver tissues were successfully demonstrated. In addition, selective visualization of lipid droplets in live mice liver tissues could be achieved at a depth of about 70 μm. These excellent properties render them as promising candidates for investigating lipid droplet-associated physiological and pathological processes in live biological samples.
脂滴与肥胖、糖尿病、炎症性疾病和癌症密切相关。一种可靠的双光子染料可在超低浓度下对活细胞和活组织中的特异性脂滴进行成像,但这种染料鲜有报道。在这项工作中,我们设计并合成了四种基于萘核的新型聚集诱导发射发光剂(AIEgens),用于特异性双光子脂滴染色。这些新分子(即 NAP AIEgens)具有较大的斯托克斯位移(>110 nm)、较高的固态荧光量子产率(高达 30%)、良好的双光子吸收截面(860 nm 处为 45-100 GM)、较高的生物相容性和良好的光稳定性。它们能在 15 分钟的短时间内以超低浓度(50 nM)特异性染色脂滴。这种超低浓度是迄今为止报道的活细胞脂滴染色的最低值。研究人员成功地在体外和体内对活细胞和活小鼠肝组织中的脂滴进行了双光子成像。此外,活体小鼠肝组织中脂滴的选择性可视化深度约为 70 μm。这些优异的特性使它们成为研究活体生物样本中脂滴相关生理和病理过程的理想候选材料。