A mechanism to photoactivate far-red/near-infrared fluorescence with infinite contrast and under mild visible illumination was designed around the photophysical properties of borondipyrromethene (BODIPY) dyes and the photochemical behavior of oxazine heterocycles. Specifically, the photoinduced and irreversible cleavage of an oxazine ring with a laser line at 405 nm extends the electronic conjugation of a BODIPY chromophore over a 3H-indole auxochrome with a 2-(4-methoxyphenyl)ethenyl substituent in position 5. This structural transformation shifts bathochromically the main absorption band of the BODIPY component to allow the selective excitation of the photochemical product with a laser line of 633 nm and produce fluorescence between 600 and 850 nm. This combination of activation, excitation, and emission wavelengths permits the visualization of the cellular blastoderm of developing Drosophila melanogaster embryos with optimal contrast and essentially no autofluorescence from the biological specimen. Furthermore, the sequential acquisition of images, after the photoactivation event, enables the tracking of individual cells within the embryos in real time. Thus, our structural design and operating principles for the photoactivation of far-red/near-infrared fluorescence can evolve into invaluable probes to monitor cellular dynamics in vivo.

中文翻译：

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可光激活的远红外/近红外BODIPY来监测体内的细胞动力学

围绕硼二吡咯并二甲基亚砜（BODIPY）染料的光物理性质和恶嗪杂环的光化学行为，设计了一种以无限大的对比度和在柔和的可见光下光激活远红/近红外荧光的机制。具体而言，用405 nm激光线对恶嗪环进行光诱导和不可逆裂解，使BODIPY生色团的电子共轭作用扩展了3 H-在5位上具有2-（4-甲氧基苯基）乙烯基取代基的吲哚辅助色素。该结构转变通过红移改变BODIPY组分的主吸收带，从而可以用633 nm的激光线选择性激发光化学产物并产生荧光在600至850 nm之间 激活，激发和发射波长的这种组合允许可视化发育中的果蝇的细胞胚层。具有最佳对比度的胚胎，并且生物学样本中基本上没有自发荧光。此外，在光激活事件之后，图像的顺序获取使得能够实时跟踪胚胎内的单个细胞。因此，我们用于远红/近红外荧光光活化的结构设计和操作原理可以发展成为监测体内细胞动力学的宝贵探针。