Abstract: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 th… Show more
“…In solution, BODIPY dyes as simple as ps1 are poor triplet sensitizers ( 41 , 42 ); therefore, the finding that ps1 acts as an efficient photosensitizer in DESC is unexpected. To obtain mechanistic insights into DESC, we performed transient absorption spectroscopy (TAS) and computational studies (Fig.…”
Section: Time-resolved Spectroscopic and Computational Studies Of Descmentioning
Photoisomerization of azobenzenes from their stable
E
isomer to the metastable
Z
state is the basis of numerous applications of these molecules. However, this reaction typically requires ultraviolet light, which limits applicability. In this study, we introduce disequilibration by sensitization under confinement (DESC), a supramolecular approach to induce the
E
-to-
Z
isomerization by using light of a desired color, including red. DESC relies on a combination of a macrocyclic host and a photosensitizer, which act together to selectively bind and sensitize
E
-azobenzenes for isomerization. The
Z
isomer lacks strong affinity for and is expelled from the host, which can then convert additional
E-
azobenzenes to the
Z
state. In this way, the host–photosensitizer complex converts photon energy into chemical energy in the form of out-of-equilibrium photostationary states, including ones that cannot be accessed through direct photoexcitation.
“…In solution, BODIPY dyes as simple as ps1 are poor triplet sensitizers ( 41 , 42 ); therefore, the finding that ps1 acts as an efficient photosensitizer in DESC is unexpected. To obtain mechanistic insights into DESC, we performed transient absorption spectroscopy (TAS) and computational studies (Fig.…”
Section: Time-resolved Spectroscopic and Computational Studies Of Descmentioning
Photoisomerization of azobenzenes from their stable
E
isomer to the metastable
Z
state is the basis of numerous applications of these molecules. However, this reaction typically requires ultraviolet light, which limits applicability. In this study, we introduce disequilibration by sensitization under confinement (DESC), a supramolecular approach to induce the
E
-to-
Z
isomerization by using light of a desired color, including red. DESC relies on a combination of a macrocyclic host and a photosensitizer, which act together to selectively bind and sensitize
E
-azobenzenes for isomerization. The
Z
isomer lacks strong affinity for and is expelled from the host, which can then convert additional
E-
azobenzenes to the
Z
state. In this way, the host–photosensitizer complex converts photon energy into chemical energy in the form of out-of-equilibrium photostationary states, including ones that cannot be accessed through direct photoexcitation.
“…Dymin/Rescue for STED (Heine et al 2017 ; Staudt et al 2011 )). Another source for (increased) phototoxicity might be the fluorophore itself (Hofmann and Weber 2021 ; Kowalska et al 2021 ), which sometimes can be solved by using a variant of the fluorophore with a different charge or binding kinetics (Bucevičius et al 2019 ; Hao et al 2021 ; Kähärä et al 2022 ). Fig.…”
Section: Important Considerations For Srmmentioning
Super-resolution microscopy (SRM) is a prime tool to study chromatin organisation at near biomolecular resolution in the native cellular environment. With fluorescent labels DNA, chromatin-associated proteins and specific epigenetic states can be identified with high molecular specificity. The aim of this review is to introduce the field of diffraction-unlimited SRM to enable an informed selection of the most suitable SRM method for a specific chromatin-related research question. We will explain both diffraction-unlimited approaches (coordinate-targeted and stochastic-localisation-based) and list their characteristic spatio-temporal resolutions, live-cell compatibility, image-processing, and ability for multi-colour imaging. As the increase in resolution, compared to, e.g. confocal microscopy, leads to a central role of the sample quality, important considerations for sample preparation and concrete examples of labelling strategies applicable to chromatin research are discussed. To illustrate how SRM-based methods can significantly improve our understanding of chromatin functioning, and to serve as an inspiring starting point for future work, we conclude with examples of recent applications of SRM in chromatin research.
“…For instance, BODIPYs for photodynamic therapy are typically incorporated with heavy atoms and/or transition metals to induce an efficient intersystem crossing (ISC) of molecules from the singlet (S 1 ) to the triplet (T 1 ) state. Additionally, the configuration and presence of rotatable bonds can induce a phototoxic effect [ 18 , 19 ]. The molecule in the triplet state then collides with nearby molecular oxygen simultaneously with energy transfer, elevating the molecular oxygen to its singlet state.…”
The straightforward synthesis of three cationic boron-dipyrromethene (BODIPY) derivatives and their mitochondria-targeting and photodynamic therapeutic (PDT) capabilities are reported. Two cancer cell lines (HeLa and MCF-7) were used to investigate the PDT activity of the dyes. Compared to their non-halogenated counterparts, halogenated BODIPY dyes exhibit lower fluorescence quantum yields and enable the efficient production of singlet oxygen species. Following LED light irradiation at 520 nm, the synthesized dyes displayed good PDT capabilities against the treated cancer cell lines, with low cytotoxicity in the dark. In addition, functionalization of the BODIPY backbone with a cationic ammonium moiety enhanced the hydrophilicity of the synthesized dyes and, consequently, their uptake by the cells. The results presented here collectively demonstrate the potential of cationic BODIPY-based dyes as therapeutic drugs for anticancer photodynamic therapy.
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