| 1. |
- Nilsson, Jesper, 1984, et al.
(författare)
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Multiphoton characterization and live cell imaging using fluorescent adenine analogue 2CNqA
- 2023
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Ingår i: Physical Chemistry Chemical Physics. - 1463-9084 .- 1463-9076. ; 25:30, s. 20218-20224
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescent nucleobase analogues (FBAs) are established tools for studying oligonucleotide structure, dynamics and interactions, and have recently also emerged as an attractive option for labeling RNA-based therapeutics. A recognized drawback of FBAs, however, is that they typically require excitation in the UV region, which for imaging in biological samples may have disadvantages related to phototoxicity, tissue penetration, and out-of-focus photobleaching. Multiphoton excitation has the potential to alleviate these issues and therefore, in this work, we characterize the multiphoton absorption properties and detectability of the highly fluorescent quadracyclic adenine analogue 2CNqA as a ribonucleotide monomer as well as incorporated, at one or two positions, into a 16mer antisense oligonucleotide (ASO). We found that 2CNqA has a two-photon absorption cross section that, among FBAs, is exceptionally high, with values of & sigma;(2PA)(700 nm) = 5.8 GM, 6.8 GM, and 13 GM for the monomer, single-, and double-labelled oligonucleotide, respectively. Using fluorescence correlation spectroscopy, we show that the 2CNqA has a high 2P brightness as the monomer and when incorporated into the ASO, comparing favorably to other FBAs. We furthermore demonstrate the usefulness of the 2P imaging mode for improving detectability of 2CNqA-labelled ASOs in live cells.
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| 2. |
- Benitez-Martin, Carlos, 1994, et al.
(författare)
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Fluorescent Molecular Photoswitches for the Generation of All-Optical Encryption Keys
- 2023
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Ingår i: Chemphotochem. - 2367-0932.
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we report a tri-component photochromic molecular cocktail that can be used to encrypt and decrypt information. The time-dependent fluorescent response of this cocktail is highly non-linear with respect to the set of inputs used (concentrations of the three photochromic components, excitation- and emission wavelengths), a property required for the generation of so-called encryption keys. The all-optical system can generate more than 80 million unique fluorescence responses by applying different input combinations and is operated using a conventional fluorimeter.
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| 3. |
- Benitez-Martin, Carlos, 1994, et al.
(författare)
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Toward Two-Photon Absorbing Dyes with Unusually Potentiated Nonlinear Fluorescence Response
- 2020
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 142:35, s. 14854-14858
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Tidskriftsartikel (refereegranskat)abstract
- The combination of two two-photon-induced processes in a Förster resonance energy transfer (FRET)-operated photochromic fluorene-dithienylethene dyad lays the foundation for the observation of a quartic dependence of the fluorescence signal on the excitation light intensity. While this photophysical behavior is predicted for a four-photon absorbing dye, the herein proposed approach opens the way to use two-photon absorbing dyes, reaching the same performance. Hence, the spatial resolution limit, being a critical parameter for applications in fluorescence imaging or data storage with common two-photon absorbing dyes, is dramatically improved.
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| 4. |
- Blaise, Nadine, et al.
(författare)
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Isomerization dynamics of a novel cis/trans-only merocyanine
- 2024
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Ingår i: ChemPhotoChem. - 2367-0932. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Merocyanines (MC) usually adopt ring opened zwitterionic structures that are interconvertible with their ring-closed spiropyran photoisomers. By methylating the phenolate oxygen, and thereby blocking the ring-closure reaction, a cis/trans-only MC photoswitch was obtained, yielding a perfect candidate for a detailed examination of the cis/trans isomerization mechanism for this class of compounds. This photoswitch displays outstanding properties including excellent photoreaction quantum yields and photoswitching turnovers. Due to the central polymethine bridge of MC, in principle eight cis (C)/trans (T) isomers are possible. Density Functional Theory (DFT) calculations revealed the CCT and TTT-isomers of the studied compound as most stable cis and trans ground state isomers, respectively. UV/vis transient absorption studies combined with conical intersection computations with the complete active space self-consistent field (CASSCF) method show that both trans/cis- and cis/trans-photoisomerizations are initiated by a rotation of the central doubled bond fragment. A hot ground state species is then formed, which undergoes a second isomerization. Thus, the cis/trans reaction proceeds via a CCT-CTT-TTT sequence and the reverse reaction via TTT-TCT-CCT.
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| 5. |
- Fleming, Cassandra, 1987, et al.
(författare)
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All-photonic kinase inhibitors: light-controlled release-and-report inhibition
- 2024
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Ingår i: Chemical Science. - 2041-6539 .- 2041-6520. ; 15:18, s. 6897-6905
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Tidskriftsartikel (refereegranskat)abstract
- Light-responsive molecular tools targeting kinases affords one the opportunity to study the underlying cellular function of selected kinases. In efforts to externally control lymphocyte-specific protein tyrosine kinase (LCK) activity, the development of release-and-report LCK inhibitors is described, in which (i) the release of the active kinase inhibitor can be controlled externally with light; and (ii) fluorescence is employed to report both the release and binding of the active kinase inhibitor. This introduces an unprecedented all-photonic method for users to both control and monitor real-time inhibitory activity. A functional cellular assay demonstrated light-mediated LCK inhibition in natural killer cells. The use of coumarin-derived caging groups resulted in rapid cellular uptake and non-specific intracellular localisation, while a BODIPY-derived caging group predominately localised in the cellular membrane. This concept of release-and-report inhibitors has the potential to be extended to other biorelevant targets where both spatiotemporal control in a cellular setting and a reporting mechanism would be beneficial.
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| 6. |
- Fleming, Cassandra L., et al.
(författare)
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All-photonic kinase inhibitors: light-controlled release-and-report inhibition
- 2024
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Ingår i: CHEMICAL SCIENCE. - 2041-6520 .- 2041-6539. ; 15:18, s. 6897-6905
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Tidskriftsartikel (refereegranskat)abstract
- Light-responsive molecular tools targeting kinases affords one the opportunity to study the underlying cellular function of selected kinases. In efforts to externally control lymphocyte-specific protein tyrosine kinase (LCK) activity, the development of release-and-report LCK inhibitors is described, in which (i) the release of the active kinase inhibitor can be controlled externally with light; and (ii) fluorescence is employed to report both the release and binding of the active kinase inhibitor. This introduces an unprecedented all-photonic method for users to both control and monitor real-time inhibitory activity. A functional cellular assay demonstrated light-mediated LCK inhibition in natural killer cells. The use of coumarin-derived caging groups resulted in rapid cellular uptake and non-specific intracellular localisation, while a BODIPY-derived caging group predominately localised in the cellular membrane. This concept of release-and-report inhibitors has the potential to be extended to other biorelevant targets where both spatiotemporal control in a cellular setting and a reporting mechanism would be beneficial. An all-photonic method is described, in which (i) the release of an active kinase inhibitor is controlled externally with light; and (ii) fluorescence is employed to report both the release and binding of the inhibitor to its corresponding target.
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| 7. |
- Naren, Gaowa, 1990, et al.
(författare)
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Rapid amplitude-modulation of a diarylethene photoswitch: en route to contrast-enhanced fluorescence imaging
- 2021
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6539 .- 2041-6520. ; 12:20, s. 7073-7078
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Tidskriftsartikel (refereegranskat)abstract
- A water soluble diarylethene (DAE) derivative that displays exceptionally intense fluorescence from the colorless open form has been synthesized and characterized using UV/vis spectroscopy and fluorescence microscopy. We show that the bright emission from the open form can be rapidly switched using amplitude modulated red light, that is, by light at wavelengths longer than those absorbed by the fluorescent species. This is highly appealing in any context where undesired background fluorescence disturbs the measurement, e.g., the autofluorescence commonly observed in fluorescence microscopy. We show that this scheme is conveniently applicable using lock-in detection, and that robust amplitude modulation of the probe fluorescence is indeed possible also in cell studies using fluorescence microscopy.
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| 8. |
- Park, Sewon, et al.
(författare)
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Photoswitchable optoelectronic properties of 2D MoSe 2 /diarylethene hybrid structures
- 2024
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Ingår i: Scientific Reports. - 2045-2322 .- 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The ability to modulate optical and electrical properties of two-dimensional (2D) semiconductors has sparked considerable interest in transition metal dichalcogenides (TMDs). Herein, we introduce a facile strategy for modulating optoelectronic properties of monolayer MoSe2 with external light. Photochromic diarylethene (DAE) molecules formed a 2-nm-thick uniform layer on MoSe2, switching between its closed- and open-form isomers under UV and visible irradiation, respectively. We have discovered that the closed DAE conformation under UV has its lowest unoccupied molecular orbital energy level lower than the conduction band minimum of MoSe2, which facilitates photoinduced charge separation at the hybrid interface and quenches photoluminescence (PL) from monolayer flakes. In contrast, open isomers under visible light prevent photoexcited electron transfer from MoSe2 to DAE, thus retaining PL emission properties. Alternating UV and visible light repeatedly show a dynamic modulation of optoelectronic signatures of MoSe2. Conductive atomic force microscopy and Kelvin probe force microscopy also reveal an increase in conductivity and work function of MoSe2/DAE with photoswitched closed-form DAE. These results may open new opportunities for designing new phototransistors and other 2D optoelectronic devices.
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| 9. |
- Royo, Raquel, et al.
(författare)
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Highly Efficient Photoninitiators Based on 4H-Pyranylidene Derivatives for Two-Photon Laser Printing
- 2023
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Ingår i: Advanced Materials Technologies. - 2365-709X. ; 8:23
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Tidskriftsartikel (refereegranskat)abstract
- A series of four donor–acceptor–donor derivatives bearing 4H-pyranylidene and 4-methylcyclohexan-1-one units as donor and acceptor groups respectively is designed, synthesized, and photophysically characterized. Both experimental and theoretical studies reveal good two-photon absorption (2PA) properties for these systems. Decoration of the exocyclic position of the 4H-pyranylidene moiety with a thiophene ring results in high 2PA cross-section values (σ2PA) ≈700 nm, and remarkably, in the region between 900 and 1000 nm. Furthermore, all chromophores are evaluated as photoinitiators (PIs) for two-photon-laser printing at 780 nm, showing superior performance compared to the commonly used commercially available PI, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. Among the studied PIs, the ones equipped with a thiophene unit at the exocyclic position of the 4H-pyranylidene moiety exhibit the highest efficiency, enabling fast printing using low laser powers with even lower concentrations of PI. Overall, this study shows the great potential of this new class of PIs for application in the field of 3D nanoprinting.
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