Ahmed Shadi Ali Hassen, Gao Xue, Zheng Yi, Wang Haoting, Zeng Su, Liu Hui, Qian Linghui
Institute of Drug Metabolism and Pharmaceutical Analysis, Research Center for Clinical Pharmacy, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China.
School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China.
Anal Chim Acta. 2025 Sep 15;1367:344299. doi: 10.1016/j.aca.2025.344299. Epub 2025 Jun 7.
Human β-galactosidase (β-gal) is a lysosomal enzyme responsible for the hydrolysis of glycoconjugates, which is overexpressed in primary ovarian cancers and regarded as a biomarker. Therefore, it is of great importance to develop fluorescent probes activatable by endogenous β-gal with strong signal-to-background contrast to facilitate ovarian cancer diagnosis. Many of the available probes suffer from small Stokes shifts, poor cellular permeability, easy diffusion away from living cells, and self-quenching when accumulated inside the lysosome, asking for the development of new turn-on probes suitable for non-invasive imaging with living cells.
The quinoline-malononitrile derivative (SDC) with aggregation-induced emission (AIE) property and large Stokes shift (∼160 nm) was conjugated with the galactose moiety via a self-immolating linker, giving SDB. Upon cleavage of the galactose by β-gal, strong red emission from SDB was detected via AIE of SDC. To improve the cell permeability, SDA containing the fully acetylated galactose was constructed, whose acetyl groups can be removed by intracellular esterases upon cell entry, resulting in unblocked SDB. Live-cell imaging demonstrated that SDA selectively distinguishes ovarian cancer cell lines (OVCAR3 and SKOV3) from others.
The AIE property of quinoline-malononitrile derived SDA allows in situ capture of β-gal activities with minimal signal diffusion, useful for long-term tracking of β-gal in living cells and promising for early cancer diagnosis.
人β-半乳糖苷酶（β-gal）是一种溶酶体酶，负责糖缀合物的水解，在原发性卵巢癌中过表达，被视为一种生物标志物。因此，开发可被内源性β-gal激活、具有强信号背景对比度的荧光探针以促进卵巢癌诊断具有重要意义。许多现有的探针存在斯托克斯位移小、细胞通透性差、易从活细胞中扩散以及在溶酶体内积累时自猝灭等问题，需要开发适用于活细胞无创成像的新型开启型探针。
将具有聚集诱导发光（AIE）特性和大斯托克斯位移（约160 nm）的喹啉-丙二腈衍生物（SDC）通过自牺牲连接子与半乳糖部分偶联，得到SDB。当β-gal切割半乳糖时，通过SDC的AIE检测到SDB发出强烈的红色荧光。为了提高细胞通透性，构建了含有完全乙酰化半乳糖的SDA，其乙酰基在细胞进入后可被细胞内酯酶去除，从而产生未受阻的SDB。活细胞成像表明，SDA能选择性地将卵巢癌细胞系（OVCAR3和SKOV3）与其他细胞区分开来。
喹啉-丙二腈衍生的SDA的AIE特性允许以最小的信号扩散原位捕获β-gal活性，有助于在活细胞中对β-gal进行长期跟踪，有望用于癌症早期诊断。
