Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Institute of Fine Chemicals, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China.
Nat Protoc. 2023 Apr;18(4):1316-1336. doi: 10.1038/s41596-022-00789-1. Epub 2023 Jan 25.
Fibrillar aggregates of the amyloid-β protein (Aβ) are the main component of the senile plaques found in brains of patients with Alzheimer's disease (AD). Development of probes allowing the noninvasive and high-fidelity mapping of Aβ plaques in vivo is critical for AD early detection, drug screening and biomedical research. QM-FN-SO (quinoline-malononitrile-thiophene-(dimethylamino)phenylsulfonate) is a near-infrared aggregation-induced-emission-active fluorescent probe capable of crossing the blood-brain barrier (BBB) and ultrasensitively lighting up Aβ plaques in living mice. Herein, we describe detailed procedures for the two-stage synthesis of QM-FN-SO and its applications for mapping Aβ plaques in brain tissues and living mice. Compared with commercial thioflavin (Th) derivatives ThT and ThS (the gold standard for detection of Aβ aggregates) and other reported Aβ plaque fluorescent probes, QM-FN-SO confers several advantages, such as long emission wavelength, large Stokes shift, ultrahigh sensitivity, good BBB penetrability and miscibility in aqueous biological media. The preparation of QM-FN-SO takes ~2 d, and the confocal imaging experiments for Aβ plaque visualization, including the preparation for mouse brain sections, take ~7 d. Notably, acquisition and analyses for in vivo visualization of Aβ plaques in mice can be completed within 1 h and require only a basic knowledge of spectroscopy and chemistry.
纤维状聚集的淀粉样蛋白-β（Aβ）是阿尔茨海默病（AD）患者大脑中发现的老年斑的主要成分。开发允许在体内非侵入性和高保真度映射 Aβ斑块的探针对于 AD 的早期检测、药物筛选和生物医学研究至关重要。QM-FN-SO（喹啉-丙二腈-噻吩-（二甲氨基）苯基磺酸盐）是一种近红外聚集诱导发射活性荧光探针，能够穿过血脑屏障（BBB），超灵敏地点亮活体小鼠中的 Aβ斑块。在此，我们描述了 QM-FN-SO 的两阶段合成的详细步骤及其在脑组织和活体小鼠中 Aβ斑块成像的应用。与商业噻唑（Th）衍生物 ThT 和 ThS（检测 Aβ聚集物的金标准）以及其他报道的 Aβ斑块荧光探针相比，QM-FN-SO 具有几个优势，例如长发射波长、大斯托克斯位移、超高灵敏度、良好的 BBB 穿透性和在水生物介质中的混溶性。QM-FN-SO 的制备需要约 2 天，用于 Aβ斑块可视化的共聚焦成像实验，包括小鼠脑切片的制备，需要约 7 天。值得注意的是，在小鼠体内可视化 Aβ斑块的体内可视化的采集和分析可以在 1 小时内完成，并且只需要对光谱学和化学有基本的了解。
