Department of Biotechnology, University of Turku, Finland.
Anal Chem. 2012 Sep 18;84(18):7708-12. doi: 10.1021/ac3008913. Epub 2012 Aug 28.
Fluorescent reporters based on lanthanide ions, such as europium chelates, enable highly sensitive detection in immunoassays and other ligand binding assays. Unfortunately they normally require UV-excitation produced by a xenon flash or nitrogen laser light source. In order to use modern solid state excitation sources such as light emitting diodes (LEDs), these reporters need to be excited at wavelengths longer than 365 nm, where high-powered ultraviolet LEDs are available. A novel ligand, 9-ethyl-3,6-bis(5',5',5',4',4'-pentafluoro-1',3'-dioxopentyl)carbazole (bdc), was synthesized to efficiently excite europium(III) at wavelengths up to 450 nm in micellar solutions, and its performance was compared to a commercially available DELFIA enhancement solution. The detection limit of Eu(III) with the bdc-ligand using 365 nm excitation was determined to be 63 fM, which is 3 times lower than with the DELFIA solution. The bdc-ligand enabled sensitive detection of europium(III) ions in solution using 365 nm excitation and displayed similar sensitivity and functionality as commercially available DELFIA enhancement solution. Therefore, this novel enhancement solution might be a feasible alternative in producing time-resolved fluorescence under LED-excitation.
基于镧系离子的荧光报告物，如铕螯合物，可在免疫测定和其他配体结合测定中实现高灵敏度检测。不幸的是，它们通常需要氙闪光灯或氮激光光源产生的紫外线激发。为了使用现代固态激发源，如发光二极管（LED），这些报告物需要在 365nm 以上的波长处被激发，而大功率紫外线 LED 在此波长处可用。合成了一种新型配体 9-乙基-3,6-双（5'，5'，5'，4'，4'-五氟-1'，3'-二氧戊基）咔唑（bdc），以在胶束溶液中在高达 450nm 的波长处有效地激发铕（III），并将其性能与市售 DELFIA 增强溶液进行了比较。使用 365nm 激发时，bdc-配体检测 Eu(III)的检测限为 63fM，比 DELFIA 溶液低 3 倍。bdc-配体可在 365nm 激发下对溶液中的铕（III）离子进行灵敏检测，并显示出与市售 DELFIA 增强溶液相似的灵敏度和功能。因此，这种新型增强溶液可能是在 LED 激发下产生时间分辨荧光的可行替代品。
