Single-molecule characterization of a bright and photostable deep-red fluorescent squaraine-figure-eight (SF8) dye
Single-molecule characterization of a bright and photostable deep-red fluorescent squaraine-figure-eight (SF8) dye
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DOI：
10.1016/j.dyepig.2022.111031
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发表时间：
2022-12-21
影响因子：
4.5
通讯作者：
Smith，Bradley
中科院分区：
文献类型：
--
作者：
Kniazev，Kirill;Guo，Tianle;Smith，Bradley
方块八号(SF8)染料是一种独特的深红色荧光染料，具有自穿线的分子体系结构，在提供结构刚性的同时，还可以包裹和保护发射的荧光色素。以前对SF8染料的细胞显微镜和体相研究表明，与传统的五甲基菁染料(如Cy5)相比，其光稳定性提高了数量级。现在在单分子水平上进行的研究表明，这些系综水平的增强可以通过提高发射量子产率、延长光漂白时间和提高总光子产量来传递到单分子水平。与Cy5相比，SF8(D4)2的单分子发射量子产额增加了三倍，光漂白前的平均时间延长了数量级，光子产额增加了20倍。其他特性，如水溶性，保护其免受亲核攻击的荧光染料，以及选择性生物标记物的靶向能力，使基于SF8的染料在生物标记、显微应用和单分子跟踪方面具有良好的应用前景。
Squaraine Figure Eight (SF8) dyes are a unique class of deep-red fluorescent dyes with self-threaded molecular architecture that provides structural rigidity while simultaneously encapsulating and protecting the emissive fluorochrome. Previous cell microscopy and bulk phase studies of SF8 dyes indicated order of magnitude enhancements in photostability over conventional pentamethine cyanine dyes such as Cy5. Studies conducted at the single molecule level now reveal that these ensemble level enhancements carry over to the single molecule level in terms of enhanced emission quantum yields, longer times to photobleaching, and enhanced total photon yields. When compared to Cy5, the SF8-based dye SF8(D4)2possesses a three-fold larger single molecule emission quantum yield, exhibits order of magnitude longer average times before photobleaching, and exhibits twenty times larger photon yields. Additional features such as water solubility, fluorochrome encapsulation to protect it against nucleophilic attack, and selective biomarker targeting capability make SF8-based dyes promising candidates for biological labeling and microscopy applications and single molecule tracking.