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Langeland J, Lindkvist TT, Kjær C, Nielsen SB. Gas-phase Förster resonance energy transfer in mass-selected and trapped ions. MASS SPECTROMETRY REVIEWS 2024; 43:477-499. [PMID: 36514825 DOI: 10.1002/mas.21828] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/21/2022] [Accepted: 11/25/2022] [Indexed: 06/17/2023]
Abstract
Förster Resonance Energy transfer (FRET) is a nonradiative process that may occur from an electronically excited donor to an acceptor when the emission spectrum of the donor overlaps with the absorption spectrum of the acceptor. FRET experiments have been done in the gas phase based on specially designed mass-spectroscopy setups with the goal to obtain structural information on biomolecular ions labeled with a FRET pair (i.e., donor and acceptor dyes) and to shed light on the energy-transfer process itself. Ions are accumulated in a radio-frequency ion trap or a Penning trap where mass selection of those of interest takes place, followed by photoexcitation. Gas-phase FRET is identified from detection of emitted light either from the donor, the acceptor, or both, or from a fragmentation channel that is specific to the acceptor when electronically excited. The challenge associated with the first approach is the collection and detection of photons emitted from a thin ion cloud that is not easily accessible while the second approach relies both on the photophysical and chemical behavior of the acceptor. In this review, we present the different instrumentation used for gas-phase FRET, including a discussion of advantages and disadvantages, and examples on how the technique has provided important structural information that is not easily obtainable otherwise. Furthermore, we describe how the spectroscopic properties of the dyes are affected by nearby electric fields, which is readily discernable from experiments on simple model systems with alkyl or π-conjugated bridges. Such spectral changes can have a significant effect on the FRET efficiency. Ideas for new directions are presented at the end with special focus on cold-ion spectroscopy.
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Affiliation(s)
- Jeppe Langeland
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
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Kjaer C, Vu-Phung A, Toft Lindkvist T, Langeland J, Brøndsted Nielsen S. Cryogenic Ion Fluorescence Spectroscopy: FRET in Rhodamine Homodimers and Heterodimers. Chemistry 2023; 29:e202302166. [PMID: 37565666 DOI: 10.1002/chem.202302166] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/02/2023] [Accepted: 08/07/2023] [Indexed: 08/12/2023]
Abstract
The internal electronic communication between two or more light-absorbers is fundamental for energy-transport processes, a field of large current interest. Here the intrinsic photophysics of homo- and heterodimers of rhodamine cations were studied where just two methylene units bridge the dyes. Gas-phase experiments were done on frozen molecular ions at cryogenic temperatures using the newly built LUNA2 mass spectroscopy setup in Aarhus. Both absorption (from fluorescence excitation) and dispersed-fluorescence spectra were measured. In the gas phase, there is no dielectric screening from solvent molecules, and the effect of charges on transition energies is maximum. Indeed, bands are redshifted compared to those of monomer dyes due to the electric field that each dye senses from the other in a dimer. Importantly, also, as two chemically identical dyes in a homodimer do not experience the same field along the long axis, each dye has separate absorption. At low temperatures, it is therefore possible to selectively excite one dye. Fluorescence is dominantly from the dye with the lowest transition energy no matter which dye is photoexcited. Hence this work unequivocally demonstrates Förster Resonance Energy Transfer even in homodimers where one dye acts as donor and the other as acceptor.
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Affiliation(s)
- Christina Kjaer
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus C, Denmark
| | - André Vu-Phung
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus C, Denmark
| | - Thomas Toft Lindkvist
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus C, Denmark
| | - Jeppe Langeland
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus C, Denmark
| | - Steen Brøndsted Nielsen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus C, Denmark
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Peng F. INFLUENCES OF ABDOMINAL CORE STRENGTH TRAINING ON SPORT DANCING. REV BRAS MED ESPORTE 2023. [DOI: 10.1590/1517-8692202329012022_0665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
ABSTRACT Introduction: The essential characteristics of the unique fitness of sport dancing are composed of the athletes' skill, quality, and physical characteristics. All are directly affected by proper abdominal core strength training. Kick strength is an important variable for controlled balance in lower limb elevation. It is produced by the combined action of the pelvic girdle and thigh muscle groups, beginning at the abdominal core. Objective: This paper explores the effect of abdominal core strength training on the quality of kicking movement in dance sports work. Methods: Forty-six college students majoring in sport dance were randomly selected as volunteers for the research. Randomly divided into control and experimental group, they participated in the experiment for four weeks. The experimental group added a specific strength exercise for the abdominal core at each class, while the control group followed only with the routine exercises. Several indicators of the athletes were tested before and after the end of the experiment. The collected variables went through the statistical methodology and data analysis. Results: The experimental group members showed significantly higher kicks than those of the control group (P<0.05). The balance and stability scores in the experimental group were also significantly higher (P<0.05). Conclusion: Abdominal core strength training significantly affects the quality of lower limb lifting movements in sports dance practitioners and significantly affects the overall performance improvement of athletes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.
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Wu R, Metternich JB, Tiwari P, Zenobi R. Adapting a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer for Gas-Phase Fluorescence Spectroscopy Measurement of Trapped Biomolecular Ions. Anal Chem 2021; 93:15626-15632. [PMID: 34784193 DOI: 10.1021/acs.analchem.1c02858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gas-phase fluorescence spectroscopy is still in its infancy, which demands further instrumental developments. In this study, a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS), equipped with a lab-developed data acquisition system, was coupled to a tunable femtosecond laser and a state-of-the-art optical system for fluorescence studies of mass-selected ions. For excitation, a laser beam was focused (beam size < 1.0 mm) into the cylindrical ICR cell. A wire mesh replaced the back trapping plate, allowing ∼10% of the fluorescence emitted from trapped ions to be collected by a lens installed beside the wire mesh. The collected fluorescence light was then transmitted outside of the mass spectrometer via fiber optics. A novel accumulation during detection (ADD) scheme was developed to increase the duty cycle of gas-phase fluorescence spectroscopy experiments. With ADD, >90% duty cycle for mass spectrometry and fluorescence experiments could be achieved. This instrument was able to perform fluorescence experiments on various ions, from simple rhodamine dyes to large biomolecules (i.e., peptides and proteins) labeled with dyes of various optical properties. A fluorescence lifetime measurement of trapped rhodamine 6G cations was also performed, yielding a value of 5.97 ± 0.23 ns. This setup has a broad mass range and decent fluorescence spectroscopy performance (i.e., the emission spectrum of rhodamine 6G can be acquired with good S/N in a minute). Finally, this setup also allows more challenging gas-phase fluorescence spectroscopy experiments, for example, of low quantum yield fluorophores and large biomolecules in their native state that appear at high m/z, which may not be doable with quadrupole ion traps (QIT).
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Affiliation(s)
- Ri Wu
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Jonas B Metternich
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Prince Tiwari
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
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Zhao Y, Sørensen ER, Lindkvist TT, Kjaer C, Brøndsted Nielsen M, Chen L, Brøndsted Nielsen S. Triangular Rhodamine Triads and Their Intrinsic Photophysics Revealed from Gas-Phase Ion Fluorescence Experiments. Chemistry 2021; 27:10875-10882. [PMID: 34060662 DOI: 10.1002/chem.202101322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Indexed: 11/10/2022]
Abstract
When ionic dyes are close together, the internal Coulomb interaction may affect their photophysics and the energy-transfer efficiency. To explore this, we have prepared triangular architectures of three rhodamines connected to a central triethynylbenzene unit (1,3,5-tris(buta-1,3-diyn-1-yl)benzene) based on acetylenic coupling reactions and measured fluorescence spectra of the isolated, triply charged ions in vacuo. We find from comparisons with previously reported monomer and dimer spectra that while polarization of the π-system causes redshifted emission, the separation between the rhodamines is too large for a Stark shift. This picture is supported by electrostatic calculations on model systems composed of three linear and polarizable ionic dyes in D3h configuration: The electric field that each dye experiences from the other two is too small to induce a dipole moment, both in the ground and the excited state. In the case of heterotrimers that contain either two rhodamine 575 (R575) and one R640 or one R575 and two R640, emission is almost purely from R640 although the polarization of the π-system expectedly diminishes the dipole-dipole interaction.
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Affiliation(s)
- Ying Zhao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | | | | | - Christina Kjaer
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Li Chen
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
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Stockett MH, Kjær C, Daly S, Bieske EJ, Verlet JRR, Nielsen SB, Bull JN. Photophysics of Isolated Rose Bengal Anions. J Phys Chem A 2020; 124:8429-8438. [PMID: 32966075 DOI: 10.1021/acs.jpca.0c07123] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dye molecules based on the xanthene moiety are widely used as fluorescent probes in bioimaging and technological applications due to their large absorption cross-section for visible light and high fluorescence quantum yield. These applications require a clear understanding of the dye's inherent photophysics and the effect of a condensed-phase environment. Here, the gas-phase photophysics of the rose bengal doubly deprotonated dianion [RB - 2H]2-, deprotonated monoanion [RB - H]-, and doubly deprotonated radical anion [RB - 2H]•- is investigated using photodetachment, photoelectron, and dispersed fluorescence action spectroscopies, and tandem ion mobility spectrometry (IMS) coupled with laser excitation. For [RB - 2H]2-, photodetachment action spectroscopy reveals a clear band in the visible (450-580 nm) with vibronic structure. Electron affinity and repulsive Coulomb barrier (RCB) properties of the dianion are characterized using frequency-resolved photoelectron spectroscopy, revealing a decreased RCB compared with that of fluorescein dianions due to electron delocalization over halogen atoms. Monoanions [RB - H]- and [RB - 2H]•- differ in nominal mass by 1 Da but are difficult to study individually using action spectroscopies that isolate target ions using low-resolution mass spectrometry. This work shows that the two monoanions are readily distinguished and probed using the IMS-photo-IMS and photo-IMS-photo-IMS strategies, providing distinct but overlapping photodissociation action spectra in the visible spectral range. Gas-phase fluorescence was not detected from photoexcited [RB - 2H]2- due to rapid electron ejection. However, both [RB - H]- and [RB - 2H]•- show a weak fluorescence signal. The [RB - H]- action spectra show a large Stokes shift of ∼1700 cm-1, while the [RB - 2H]•- action spectra show no appreciable Stokes shift. This difference is explained by considering geometries of the ground and fluorescing states.
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Affiliation(s)
- Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus 8000, Denmark
| | - Steven Daly
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumiére Matiére UMR 5306, F-69100 Villeurbanne, France
| | - Evan J Bieske
- School of Chemistry, University of Melbourne, Parkville VIC 3010, Australia
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | | | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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Petersen AU, Kjær C, Jensen C, Brøndsted Nielsen M, Brøndsted Nielsen S. Gas‐Phase Ion Fluorescence Spectroscopy of Tailor‐made Rhodamine Homo‐ and Heterodyads: Quenching of Electronic Communication by π‐Conjugated Linkers. Angew Chem Int Ed Engl 2020; 59:20946-20955. [DOI: 10.1002/anie.202008314] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/11/2020] [Indexed: 01/19/2023]
Affiliation(s)
| | - Christina Kjær
- Department of Physics and Astronomy Aarhus University Denmark
| | - Cecilie Jensen
- Department of Chemistry University of Copenhagen Denmark
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Petersen AU, Kjær C, Jensen C, Brøndsted Nielsen M, Brøndsted Nielsen S. Gas‐Phase Ion Fluorescence Spectroscopy of Tailor‐made Rhodamine Homo‐ and Heterodyads: Quenching of Electronic Communication by π‐Conjugated Linkers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | - Christina Kjær
- Department of Physics and Astronomy Aarhus University Denmark
| | - Cecilie Jensen
- Department of Chemistry University of Copenhagen Denmark
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