Li Songjiao, Wang Peipei, Ye Miantai, Yang Ke, Cheng Dan, Mao Zhiqiang, He Longwei, Liu Zhihong
Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Department of Pharmacy and Pharmacology, Hengyang Medical School, University of South China, Hengyang 421002, China.
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, China.
Anal Chem. 2023 Mar 21;95(11):5133-5141. doi: 10.1021/acs.analchem.3c00226. Epub 2023 Mar 9.
Dual-channel fluorescent probes could respond to a specific target and emit different wavelengths of fluorescence before and after the response. Such probes could alleviate the influence caused by the variation of the probe concentration, excitation intensity, and so on. However, for most dual-channel fluorescent probes, the probe and fluorophore faced spectral overlap, which reduced sensitivity and accuracy. Herein, we introduced a cysteine (Cys)-responsive and near-infrared (NIR) emissive AIEgen (named ) with good biocompatibility to dual-channel monitor Cys in mitochondria and lipid droplets (LDs) during cell apoptosis through wash-free fluorescence bio-imaging. can label mitochondria with bright fluorescence around 750 nm, and after reacting with Cys, the reaction product could spontaneously target LDs with emissions around 650 nm. Such spatially separated dual-channel fluorescence responses could significantly improve detection sensitivity and accuracy. Furthermore, the Cys-triggered dual-channel fluorescence imaging in LDs and mitochondria during apoptosis induced by UV light exposure, HO, or LPS treatment is clearly observed for the first time. Besides, we also report here that can be used to image subcellular Cys in different cell lines by measuring the fluorescence intensities of different emission channels. In particular, shows superior utility for the in vivo imaging of apoptosis in acute and chronic epilepsy mice. In brief, the newly designed NIR AIEgen can respond to Cys and separate two fluorescence signals to mitochondria and LDs, respectively, to study Cys-related apoptosis.
双通道荧光探针可以对特定目标做出响应，并在响应前后发射不同波长的荧光。这类探针可以减轻由探针浓度、激发强度等变化所造成的影响。然而，对于大多数双通道荧光探针而言，探针与荧光团存在光谱重叠，这降低了灵敏度和准确性。在此，我们引入了一种对半胱氨酸（Cys）有响应且发射近红外（NIR）光的聚集诱导发光体（AIEgen，命名为 ），其具有良好的生物相容性，可通过免洗荧光生物成像对细胞凋亡过程中线粒体和脂滴（LDs）内的Cys进行双通道监测。 可以用750 nm左右的明亮荧光标记线粒体，与Cys反应后，反应产物 能够自发靶向脂滴，发射波长在650 nm左右。这种空间上分离的双通道荧光响应可以显著提高检测灵敏度和准确性。此外，首次清晰观察到在紫外线照射、HO或LPS处理诱导的细胞凋亡过程中，脂滴和线粒体中由Cys触发的双通道荧光成像。此外，我们在此还报告 可通过测量不同发射通道的荧光强度用于对不同细胞系中的亚细胞Cys进行成像。特别地， 在急性和慢性癫痫小鼠的细胞凋亡体内成像中显示出卓越的效用。简而言之，新设计的近红外AIEgen 可以对Cys做出响应，并将两个荧光信号分别分离到线粒体和脂滴，以研究与Cys相关的细胞凋亡。
