Laboratory of Medicinal and Technological Chemistry, University of Brasília (IQ-UnB), Campus Universitario Darcy Ribeiro, Brasilia 70904970, P.O. Box 4478, DF, Brazil.
Acc Chem Res. 2015 Jun 16;48(6):1560-9. doi: 10.1021/ar500468p. Epub 2015 May 15.
This Account describes the origins, features, importance, and trends of the use of fluorescent small-molecule 2,1,3-benzothiadiazole (BTD) derivatives as a new class of bioprobes applied to bioimaging analyses of several (live and fixed) cell types. BTDs have been successfully used as probes for a plethora of biological analyses for only a few years, and the impressive responses obtained by using this important class of heterocycle are fostering the development of new fluorescent BTDs and expanding the biological applications of such derivatives. The first use of a fluorescent small-molecule BTD derivative as a selective cellular probe dates back to 2010, and since then impressive advances have been described by us and others. The well-known limitations of classical scaffolds urged the development of new classes of bioprobes. Although great developments have been achieved by using classical scaffolds such as coumarins, BODIPYs, fluoresceins, rhodamines, cyanines, and phenoxazines, there is still much to be done, and BTDs aim to succeed where these dyes have shown their limitations. Important organelles and cell components such as nuclear DNA, mitochondria, lipid droplets, and others have already been successfully labeled by fluorescent small-molecule BTD derivatives. New technological systems that use BTDs as the fluorophores for bioimaging experiments have been described in recent scientific literature. The successful application of BTDs as selective bioprobes has led some groups to explore their potential for use in studying membrane pores or tumor cells under hypoxic conditions. Finally, BTDs have also been used as fluorescent tags to investigate the action mechanism of some antitumor compounds. The attractive photophysical data typically observed for π-extended BTD derivatives is fostering interest in the use of this new class of bioprobes. Large Stokes shifts, large molar extinction coefficients, high quantum yields, high stability when stored in solution or as pure solids, no fading even after long periods of irradiation, bright emissions with no blinking, good signal-to-noise ratios, efficiency to transpose the cell membrane, and irradiation preferentially in the visible-light region are just some features noted by using BTDs. As the pioneering group in the use of fluorescent small-molecule BTDs for bioimaging purposes, we feel pleased to share our experience, results, advances, and personal perspectives with the readers of this Account. The readers will clearly note the huge advantages of using fluorescent BTDs over classical scaffolds, and hopefully they will be inspired and motivated to further BTD technology in the fields of molecular and cellular biology.
本文描述了荧光小分子 2,1,3-苯并噻二唑 (BTD) 衍生物作为一类新的生物探针在多种（活细胞和固定细胞）细胞类型的生物成像分析中的应用的起源、特点、重要性和趋势。BTD 作为探针仅用于生物分析数年，但使用这种重要杂环的令人印象深刻的响应正在促进新的荧光 BTD 的开发，并扩展此类衍生物的生物应用。首例荧光小分子 BTD 衍生物作为选择性细胞探针的应用可追溯到 2010 年，此后我们和其他人都取得了令人瞩目的进展。经典支架的众所周知的局限性促使开发新的生物探针类别。尽管使用香豆素、BODIPY、荧光素、罗丹明、花菁和吩嗪等经典支架取得了巨大的发展，但仍有许多工作要做，而 BTD 旨在弥补这些染料的局限性。已经成功地使用荧光小分子 BTD 衍生物标记了重要的细胞器和细胞成分，如核 DNA、线粒体、脂滴等。最近的科学文献中描述了使用 BTD 作为生物成像实验荧光团的新技术系统。BTD 作为选择性生物探针的成功应用促使一些小组探索其在研究缺氧条件下的膜孔或肿瘤细胞中的潜在用途。最后，BTD 还被用作荧光标记物来研究一些抗肿瘤化合物的作用机制。对于π-扩展 BTD 衍生物通常观察到的有吸引力的光物理数据正在激发对使用这种新的生物探针类别的兴趣。大斯托克斯位移、大摩尔消光系数、高量子产率、在溶液中或作为纯固体储存时的高稳定性、即使在长时间照射后也不会褪色、无闪烁的明亮发射、良好的信噪比、穿过细胞膜的效率以及优先在可见光区域照射只是使用 BTD 时注意到的一些特点。作为使用荧光小分子 BTD 进行生物成像目的的先驱小组，我们很高兴与读者分享我们的经验、结果、进展和个人观点。读者将清楚地注意到使用荧光 BTD 相对于经典支架的巨大优势，并希望他们受到启发和激励，在分子和细胞生物学领域进一步推进 BTD 技术。
