Chemistry and Advanced Materials, Unit of Materials Science and Environmental Engineering, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, 33014, Tampere, Finland.
Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
Photochem Photobiol Sci. 2022 Sep;21(9):1677-1687. doi: 10.1007/s43630-022-00250-y. Epub 2022 Jul 7.
For long-term live-cell fluorescence imaging and biosensing, it is crucial to work with a dye that has high fluorescence quantum yield and photostability without being detrimental to the cells. In this paper, we demonstrate that neutral boron-dipyrromethene (BODIPY)-based molecular rotors have great properties for high-light-dosage demanding live-cell fluorescence imaging applications that require repetitive illuminations. In molecular rotors, an intramolecular rotation (IMR) allows an alternative route for the decay of the singlet excited state (S) via the formation of an intramolecular charge transfer state (CT). The occurrence of IMR reduces the probability of the formation of a triplet state (T) which could further react with molecular oxygen (O) to form cytotoxic reactive oxygen species, e.g., singlet oxygen (O). We demonstrate that the oxygen-related nature of the phototoxicity for BODIPY derivatives can be significantly reduced if a neutral molecular rotor is used as a probe. The studied neutral molecular rotor probe shows remarkably lower phototoxicity when compared with both the non-rotating BODIPY derivative and the cationic BODIPY-based molecular rotor in different light dosages and dye concentrations. It is also evident that the charge and localization of the fluorescent probe are as significant as the IMR in terms of the phototoxicity in a long-term live-cell imaging.
对于长期的活细胞荧光成像和生物传感，使用具有高光剂量要求的活细胞荧光成像应用所需的高荧光量子产率和光稳定性而不会对细胞造成损害的染料至关重要。在本文中，我们证明基于中性硼二吡咯甲川（BODIPY）的分子转子具有很好的性质，适用于需要重复照明的高光剂量要求的活细胞荧光成像应用。在分子转子中，分子内旋转（IMR）允许通过形成分子内电荷转移态（CT）来替代单重激发态（S）的衰减途径。IMR 的发生降低了三重态（T）形成的概率，三重态（T）可能进一步与分子氧（O）反应形成细胞毒性活性氧，例如单线态氧（O）。我们证明，如果使用中性分子转子作为探针，可以显著降低 BODIPY 衍生物的光毒性与氧相关的性质。与非旋转 BODIPY 衍生物和阳离子 BODIPY 基分子转子相比，所研究的中性分子转子探针在不同的光剂量和染料浓度下显示出明显更低的光毒性。显然，在长期活细胞成像中，荧光探针的电荷和定位与 IMR 一样重要，对光毒性有重要影响。
