Single-Atom Fluorescence Switch: A General Approach toward Visible-Light-Activated Dyes for Biological Imaging

• Published in: Journal of the American Chemical Society Vol. 141; no. 37; pp. 14699 - 14706
• Main Authors: Tang, Juan, Robichaux, Michael A, Wu, Kuan-Lin, Pei, Jingqi, Nguyen, Nhung T, Zhou, Yubin, Wensel, Theodore G, Xiao, Han
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 18.09.2019; Amer Chemical Soc
• Subjects: Adipocytes - metabolism; Animals; Cells, Cultured; Chemistry; Chemistry, Multidisciplinary; CHO Cells; Cricetinae; Cricetulus; Fluorescence; Fluorescent Dyes - chemistry; Light; Microscopy, Fluorescence - methods; Physical Sciences; Science & Technology; Sulfhydryl Compounds - chemistry; BODIPY; PHOTOACTIVATABLE FLUOROPHORES; OXYGEN QUANTUM YIELDS; DESULFURIZATION; AZIDE; LIPID DROPLETS; PROBES
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.9b06237

Photoactivatable fluorophores afford powerful molecular tools to improve the spatial and temporal resolution of subcellular structures and dynamics. By performing a single sulfur-for-oxygen atom replacement within common fluorophores, we have developed a facile and general strategy to obtain photoactivatable fluorogenic dyes across a broad spectral range. Thiocarbonyl substitution within fluorophores results in significant loss of fluorescence via a photoinduced electron transfer-quenching mechanism as suggested by theoretical calculations. Significantly, upon exposure to air and visible light residing in their absorption regime (365–630 nm), thio-caged fluorophores can be efficiently desulfurized to their oxo derivatives, thus restoring strong emission of the fluorophores. The effective photoactivation makes thio-caged fluorophores promising candidates for super-resolution imaging, which was realized by photoactivated localization microscopy (PALM) with low-power activation light under physiological conditions in the absence of cytotoxic additives (e.g., thiols, oxygen scavengers), a feature superior to traditional PALM probes. The versatility of this thio-caging strategy was further demonstrated by multicolor super-resolution imaging of lipid droplets and proteins of interest.