Rhodamines NN: A Novel Class of Caged Fluorescent Dyes
Rhodamines NN: A Novel Class of Caged Fluorescent Dyes
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DOI：
10.1002/anie.201000150
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Hell, Stefan W.
中科院分区：
文献类型：
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作者：
Belov, Vladimir N.;Wurm, Christian A.;Hell, Stefan W.
笼状（即掩蔽）荧光染料通过掺入光化学不稳定基团而保持其非荧光状态。光敏掩蔽基团或“分子笼”可以通过用近紫外光照射而被切断，从而使染料发荧光。[1a-c]笼状荧光染料对于生物成像具有巨大的兴趣，因为它们可以用于例如蛋白质动力学分析，[1d，e]荧光显微镜，[1f]和远场光学纳米镜。[1g]邻硝基苄基常用作掩蔽基团;[1a-c]然而，这些染料的使用受到限制，因为它们的合成相当复杂，并且通过光解释放出不需要的副产物。在此，我们报道了一类新型笼状化合物-罗丹明NN染料的合成和表征，其具有结合到螺-9H-咕吨片段中的2-重氮酮（COCNN）掩蔽基团（分别为方案1和3中的化合物3和9-R）。这个非常简单和小的笼状基团是一类新的具有显着性质的掩蔽罗丹明的核心元素。罗丹明NN染料可以容易地制备并与生物分子缀合，它们在标准照射条件（波长420 nm）下经历快速释放，形成高度荧光的罗丹明衍生物，并且它们可以用于水性缓冲液以及用于成像应用中的各种包埋介质中。在显微镜下，这些新的罗丹明可以单独或与传统的荧光染料和可切换的罗丹明螺酰胺组合用作标记。[2]在后一种情况下，它们能够实现基于逐步激活和检测几种荧光标记物的新成像方案。新的罗丹明NN衍生物（9-R）与罗丹明S的光致变色螺酰胺[2 e]和正常的（未笼化的）N，N，N ′，N ′-四甲基罗丹明的组合导致了单色多标记成像
Caged (that is, masked) fluorescent dyes are maintained in their nonfluorescent state by the incorporation of a photochemical labile group. The photosensitive masking group or “molecular cage” can be cleaved-off by irradiation with near-UV light, thereby rendering the dye fluorescent.[1a–c] Caged fluorescent dyes are of enormous interest for biological imaging because they may be used, for example, for the analysis of protein dynamics,[1d, e] multicolor fluorescence microscopy,[1f] and far-field optical nanoscopy.[1g] o-Nitrobenzyl groups are often used as masking groups;[1a–c] however, the use of these dyes is limited because of their rather complex synthesis and the unwanted by-products liberated by photolysis.Herein we report on the synthesis and characterization of a novel class of caged compounds—rhodamineNN dyes, which have a 2-diazoketone (COCNN) caging group incorporated into a spiro-9H-xanthene fragment (compounds 3 and 9-R in Schemes 1 and 3, respectively). This very simple and small caging group is the core element of a new class of masked rhodamines that have remarkable properties. The rhodamine NN dyes can be easily prepared and conjugated with biomolecules, they undergo rapid uncaging under standard irradiation conditions (with wavelengths 420 nm) with formation of highly fluorescent rhodamine derivatives, and they can be used in aqueous buffers, as well as in various embedding media utilized in imaging applications. In microscopy, these novel rhodamines may be used as labels alone or in combination with conventional fluorescent dyes and switchable rhodamine spiroamides.[2] In the latter case, they enable new imaging protocols based on the stepwise activation and detection of several fluorescent markers. The combination of the new rhodamine NN derivative (9-R) with the photochromic spiroamide of rhodamine S [2e] and a normal (uncaged) N, N, N’, N’-tetramethylrhodamine resulted in a monochoromatic multilabel imaging