Photochemical reactions can be designed to convert either irreversibly or reversibly a nonemissive reactant into an emissive product. The irreversible disconnection of a photocleavable group from an emissive chromophore or the reversible interconversion of a photochromic component is generally exploited to implement these operating principles for fluorescence switching. In both instances, the interplay of activating radiation, to convert the nonemissive state into the emissive species, and exciting radiation, to produce fluorescence from the latter, can be exploited to switch fluorescence on in a given area of interest at a precise interval of time. Such a level of spatiotemporal control provides the opportunity to reconstruct sub-diffraction images with resolution at the nanometer level. Indeed, closely-spaced emitters can be switched on under photochemical control at distinct intervals of time and localized independently at the single-molecule level. In combination with appropriate intracellular targeting strategies, some of these photoactivatable fluorophores can be switched and localized inside live cells to permit the visualization of sub-cellular structures with a spatial resolution that would be impossible to achieve with conventional fluorophores. As a result, photoactivatable fluorophores can become invaluable probes for the implementation of super-resolution imaging schemes aimed at the elucidation of the fundamental factors controlling cellular functions at the molecular level.

中文翻译：

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用于活细胞单分子定位显微镜的可光活化荧光团。

可以设计光化学反应以将不可发射的反应物不可逆地或可逆地转化为发射产物。通常利用光可裂解基团与发射发色团的不可逆分离或光致变色组分的可逆相互转化来实现这些用于荧光转换的操作原理。在这两种情况下，可以利用激活辐射（将非发光状态转换为发射物种）和激发辐射（从后者产生荧光）之间的相互作用来在给定的目标区域内以精确的时间间隔打开荧光。 。这种水平的时空控制提供了重建具有纳米级分辨率的亚衍射图像的机会。确实，紧密排列的发射器可以在光化学控制下以不同的时间间隔打开，并独立定位在单分子水平上。结合适当的细胞内靶向策略，可以将这些可光激活的荧光团中的一些切换并定位在活细胞内部，以实现具有传统荧光团无法实现的空间分辨率的亚细胞结构的可视化。结果，可光活化的荧光团可以成为实现超分辨率成像方案的宝贵探针，旨在阐明在分子水平上控制细胞功能的基本因素。结合适当的细胞内靶向策略，可以将这些可光激活的荧光团中的一些切换并定位在活细胞内部，以实现具有传统荧光团无法实现的空间分辨率的亚细胞结构的可视化。结果，可光活化的荧光团可以成为实现超分辨率成像方案的宝贵探针，旨在阐明在分子水平上控制细胞功能的基本因素。结合适当的细胞内靶向策略，可以将这些可光激活的荧光团中的一些切换并定位在活细胞内部，以实现具有传统荧光团无法实现的空间分辨率的亚细胞结构的可视化。结果，可光活化的荧光团可以成为实现超分辨率成像方案的宝贵探针，旨在阐明在分子水平上控制细胞功能的基本因素。