Fluorescent sensor for Cu2+ with a tunable emission wavelength.
Fluorescent sensor for Cu2+ with a tunable emission wavelength.
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DOI：
10.1021/ic050362d
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发表时间：
2005-07
影响因子：
4.6
通讯作者：
A. Mokhir;A. Kiel;D. Herten;R. Kraemer
中科院分区：
文献类型：
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作者：
A. Mokhir;A. Kiel;D. Herten;R. Kraemer
提出了一种易于调节发射波长的荧光金属离子传感概念，并通过检测 Cu(2+) 证明了其原理。荧光素染料用金属螯合基团进行化学修饰，然后连接到 ss-DNA 的末端。其与用另一种荧光染料 (ATTO 590) 修饰的互补 ss-DNA 结合，发射更长的波长。在组装的双链体中，观察到荧光素供体（在 470 nm 处激发）和 ATTO 590 受体（在 624 nm 处发射）之间的荧光共振能量转移 (FRET)。刚性 DNA 双螺旋内的正确定位可防止两种染料发生分子内接触猝灭。传感器的螯合单元与顺磁 Cu(2+) 离子的协调导致荧光素染料的直接荧光猝灭和 ATTO 590 在 624 nm 处发射的间接（通过 FRET 损失）猝灭。因此，受体染料的发射可用于监测 Cu(2+) 的浓度，检测限为 20 nM。通过用其他市售 DNA 受体染料缀合物替换 ATTO-DNA，可以轻松调节发射波长。发射 >600 nm 的荧光金属离子传感器非常罕见。调节发射波长的可能性对于优化此类传感器应用于生物样品非常重要，生物样品通常在 <550 nm 处表现出广泛的自发荧光。
A concept of fluorescent metal ion sensing with an easily tunable emission wavelength is presented and its principle demonstrated by detection of Cu(2+). A fluorescein dye was chemically modified with a metal chelating group and then attached to the terminus of ss-DNA. This was combined with a complementary ss-DNA modified with another fluorescent dye (ATTO 590), emitting at a longer wavelength. In the assembled duplex, fluorescence resonance energy transfer (FRET) between the fluorescein donor (excited at 470 nm) and the ATTO 590 acceptor (emitting at 624 nm) is observed. Proper positioning within the rigid DNA double helix prevents intramolecular contact quenching of the two dyes. Coordination of paramagnetic Cu(2+) ions by the chelating unit of the sensor results in direct fluorescence quenching of the fluorescein dye and indirect (by loss of FRET) quenching of the ATTO 590 emission at 624 nm. As a result, emission of the acceptor dye can be used for monitoring of the concentration of Cu(2+), with a 20 nM detection limit. The emission wavelength is readily tuned by replacement of ATTO-DNA by other commercially available DNA-acceptor dye conjugates. Fluorescent metal ion sensors emitting at >600 nm are very rare. The possibility of tuning the emission wavelength is important with respect to the optimization of this sensor type for application to biological samples, which usually show broad autofluorescence at <550 nm.