Department of Pharmacy, University of Pisa, Via Bonanno Pisano 6, 56126 Pisa, Italy.
Chemistry and Industrial Chemistry Department, University of Pisa, Via G. Moruzzi 3, 56126 Pisa, Italy.
Molecules. 2020 Dec 24;26(1):58. doi: 10.3390/molecules26010058.
The development of lanthanide-based luminescent probes with a long emission lifetime has the potential to revolutionize imaging-based diagnostic techniques. By a rational design strategy taking advantage of computational predictions, a novel, water-soluble Eu complex from a cyclen-based ligand bearing 1,3-disubstituted benzo[h]isoquinoline arms was realized. The ligand has been obtained overcoming the lack of reactivity of position 3 of the isoquinoline moiety. Notably, steric hindrance of the heteroaromatic chromophore allowed selective and stoichiometry-controlled insertion of two or three antennas on the cyclen platform without any protection strategy. The complex bears a fourth heptanoic arm for easy conjugation to biomolecules. This new chromophore allowed the sensitization of the metal center either with one or two photons excitation. The suitability as a luminescent bioprobe was validated by imaging BMI1 oncomarker in lung carcinoma cells following an established immunofluorescence approach. The use of a conventional epifluorescence microscope equipped with a linear structured illumination module disclosed a simple and inexpensive way to image confocally Ln-bioprobes by single photon excitation in the 350-400 nm window, where ordinary confocal systems have no excitation sources.
具有长发射寿命的镧系发光探针的发展有可能彻底改变基于成像的诊断技术。通过利用计算预测的合理设计策略，实现了一种新型的基于环戊二烯的配体的水溶性 Eu 配合物，该配体带有 1,3-取代的苯并[h]异喹啉臂。该配体已经通过克服异喹啉部分 3 位的反应性缺乏而获得。值得注意的是，杂芳族发色团的空间位阻允许在环戊二烯平台上选择性和计量控制地插入两个或三个天线，而无需任何保护策略。该配合物带有第四个庚酸臂，便于与生物分子连接。这种新的发色团允许用一个或两个光子激发来敏化金属中心。通过采用已建立的免疫荧光方法在肺癌细胞中对 BMI1 致癌标记物进行成像，验证了其作为发光生物探针的适用性。使用配备线性结构照明模块的传统荧光显微镜揭示了一种简单且廉价的方法，通过在 350-400nm 窗口中单光子激发来共焦成像 Ln-生物探针，普通共焦系统在该窗口中没有激发源。
