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Bacalum M, Radu M, Osella S, Knippenberg S, Ameloot M. Generalized polarization and time-resolved fluorescence provide evidence for different populations of Laurdan in lipid vesicles. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 250:112833. [PMID: 38141326 DOI: 10.1016/j.jphotobiol.2023.112833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/29/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
The solvatochromic dye Laurdan is widely used in sensing the lipid packing of both model and biological membranes. The fluorescence emission maximum shifts from about 440 nm (blue channel) in condensed membranes (So) to about 490 nm (green channel) in the liquid-crystalline phase (Lα). Although the fluorescence intensity based generalized polarization (GP) is widely used to characterize lipid membranes, the fluorescence lifetime of Laurdan, in the blue and the green channel, is less used for that purpose. Here we explore the correlation between GP and fluorescence lifetimes by spectroscopic measurements on the So and Lα phases of large unilamellar vesicles of DMPC and DPPC. A positive correlation between GP and the lifetimes is observed in each of the optical channels for the two lipid phases. Microfluorimetric determinations on giant unilamellar vesicles of DPPC and DOPC at room temperature are performed under linearly polarized two-photon excitation to disentangle possible subpopulations of Laurdan at a scale below the optical resolution. Fluorescence intensities, GP and fluorescence lifetimes depend on the angle between the orientation of the linear polarization of the excitation light and the local normal to the membrane of the optical cross-section. This angular variation depends on the lipid phase and the emission channel. GP and fluorescence intensities in the blue and green channel in So and in the blue channel in Lα exhibit a minimum near 90o. Surprisingly, the intensity in the green channel in Lα reaches a maximum near 90o. The fluorescence lifetimes in the two optical channels also reach a pronounced minimum near 90o in So and Lα, apart from the lifetime in the blue channel in Lα where the lifetime is short with minimal angular variation. To our knowledge, these experimental observations are the first to demonstrate the existence of a bent conformation of Laurdan in lipid membranes, as previously suggested by molecular dynamics calculations.
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Affiliation(s)
- Mihaela Bacalum
- Department of Life and Environmental Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, Reactorului, 30, Măgurele 077125, Romania
| | - Mihai Radu
- Department of Life and Environmental Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, Reactorului, 30, Măgurele 077125, Romania
| | - Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Stefan Knippenberg
- Biomedical Research Institute, Hasselt University, Agoralaan Bldg. C, 3590 Diepenbeek, Belgium; Theory Lab, Hasselt University, Agoralaan Bldg. D, 3590 Diepenbeek, Belgium
| | - Marcel Ameloot
- Biomedical Research Institute, Hasselt University, Agoralaan Bldg. C, 3590 Diepenbeek, Belgium.
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2
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Benetis NP, Paloncýová M, Knippenberg S. Multiscale Modeling Unravels the Influence of Biomembranes on the Photochemical Properties of Embedded Anti-Oxidative Polyphenolic and Phenanthroline Chelating Dyes. J Phys Chem B 2023; 127:212-227. [PMID: 36563093 DOI: 10.1021/acs.jpcb.2c07072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The embedding of caffeate methyl ester, the flavonoids luteolin and quercetin, and the o-phenanthroline and neocuproine in a liquid disordered lipid bilayer has been studied through extensive atomistic calculations. The location and the orientation of these bio-active antioxidants are explained and analyzed. While the two phenanthrolines strongly associate with the lipid tail region, the other three compounds are rather found among the head groups. The simulations showcase conformational changes of the flavonoids. Through the use of a hybrid quantum mechanics-molecular mechanics scheme and supported by a profound benchmarking of the electronic excited-state method for these compounds, the influence of the anisotropic environment on the compounds' optical properties is analyzed. Influences of surrounding water molecules and of the polar parts of the lipids on the transition dipole moments and excited-state dipole moments are weighted with respect to a change in conformation. The current study highlights the importance of the mapping of molecular interactions in model membranes and pinpoints properties, which can be biomedically used to discriminate and detect different lipid environments.
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Affiliation(s)
| | - Markéta Paloncýová
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technologies and Research Institute, Palacký University Olomouc, Křížkovského 8, Olomouc779 00, Czech Republic
| | - Stefan Knippenberg
- Hasselt University, Theory Lab, Agoralaan Building D, 3590Diepenbeek, Belgium.,Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), Université Libre de Bruxelles, 50 Avenue F. Roosevelt, C.P. 160/09, B-1050Brussels, Belgium
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3
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Fluorescent Multifunctional Organic Nanoparticles for Drug Delivery and Bioimaging: A Tutorial Review. Pharmaceutics 2022; 14:pharmaceutics14112498. [PMID: 36432688 PMCID: PMC9698844 DOI: 10.3390/pharmaceutics14112498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/08/2022] [Accepted: 11/08/2022] [Indexed: 11/19/2022] Open
Abstract
Fluorescent organic nanoparticles (FONs) are a large family of nanostructures constituted by organic components that emit light in different spectral regions upon excitation, due to the presence of organic fluorophores. FONs are of great interest for numerous biological and medical applications, due to their high tunability in terms of composition, morphology, surface functionalization, and optical properties. Multifunctional FONs combine several functionalities in a single nanostructure (emission of light, carriers for drug-delivery, functionalization with targeting ligands, etc.), opening the possibility of using the same nanoparticle for diagnosis and therapy. The preparation, characterization, and application of these multifunctional FONs require a multidisciplinary approach. In this review, we present FONs following a tutorial approach, with the aim of providing a general overview of the different aspects of the design, preparation, and characterization of FONs. The review encompasses the most common FONs developed to date, the description of the most important features of fluorophores that determine the optical properties of FONs, an overview of the preparation methods and of the optical characterization techniques, and the description of the theoretical approaches that are currently adopted for modeling FONs. The last part of the review is devoted to a non-exhaustive selection of some recent biomedical applications of FONs.
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4
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Exhibiting environment sensitive optical properties through multiscale modelling: A study of photoactivatable probes. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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5
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Grabarz AM, Ośmiałowski B. Benchmarking Density Functional Approximations for Excited-State Properties of Fluorescent Dyes. Molecules 2021; 26:7434. [PMID: 34946515 PMCID: PMC8703901 DOI: 10.3390/molecules26247434] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/28/2021] [Accepted: 12/04/2021] [Indexed: 12/05/2022] Open
Abstract
This study presents an extensive analysis of the predictive power of time-dependent density functional theory in determining the excited-state properties of two groups of important fluorescent dyes, difluoroboranes and hydroxyphenylimidazo[1,2-a]pyridine derivatives. To ensure statistically meaningful results, the data set is comprised of 85 molecules manifesting diverse photophysical properties. The vertical excitation energies and dipole moments (in the electronic ground and excited states) of the aforementioned dyes were determined using the RI-CC2 method (reference) and with 18 density functional approximations (DFA). The set encompasses DFAs with varying amounts of exact exchange energy (EEX): from 0% (e.g., SVWN, BLYP), through a medium (e.g., TPSSh, B3LYP), up to a major contribution of EEX (e.g., BMK, MN15). It also includes range-separated hybrids (CAM-B3LYP, LC-BLYP). Similar error profiles of vertical energy were obtained for both dye groups, although the errors related to hydroxyphenylimidazopiridines are significantly larger. Overall, functionals including 40-55% of EEX (SOGGA11-X, BMK, M06-2X) ensure satisfactory agreement with the reference vertical excitation energies obtained using the RI-CC2 method; however, MN15 significantly outperforms them, providing a mean absolute error of merely 0.04 eV together with a very high correlation coefficient (R2 = 0.98). Within the investigated set of functionals, there is no single functional that would equally accurately determine ground- and excited-state dipole moments of difluoroboranes and hydroxyphenylimidazopiridine derivatives. Depending on the chosen set of dyes, the most accurate μGS predictions were delivered by MN15 incorporating a major EEX contribution (difluoroboranes) and by PBE0 containing a minor EEX fraction (hydroxyphenylimidazopiridines). Reverse trends are observed for μES, i.e., for difluoroboranes the best results were obtained with functionals including a minor fraction of EEX, specifically PBE0, while in the case of hydroxyphenylimidazopiridines, much more accurate predictions were provided by functionals incorporating a major EEX contribution (BMK, MN15).
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Affiliation(s)
- Anna M. Grabarz
- Faculty of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland
| | - Borys Ośmiałowski
- Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, PL-87100 Toruń, Poland;
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Le Breton G, Bonhomme O, Brevet PF, Benichou E, Loison C. First hyperpolarizability of water at the air-vapor interface: a QM/MM study questions standard experimental approximations. Phys Chem Chem Phys 2021; 23:24932-24941. [PMID: 34726679 DOI: 10.1039/d1cp02258j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Surface Second-Harmonic Generation (S-SHG) experiments provide a unique approach to probe interfaces. One important issue for S-SHG is how to interpret the S-SHG intensities at the molecular level. Established frameworks commonly assume that each molecule emits light according to an average molecular hyperpolarizability tensor β(-2ω,ω,ω). However, for water molecules, this first hyperpolarizability is known to be extremely sensitive to their environment. We have investigated the molecular first hyperpolarizability of water molecules within the liquid-vapor interface, using a quantum description with explicit, inhomogeneous electrostatic embedding. The resulting average molecular first hyperpolarizability tensor depends on the distance relative to the interface, and it practically respects the Kleinman symmetry everywhere in the liquid. Within this numerical approach, based on the dipolar approximation, the water layer contributing to the Surface Second Harmonic Generation (S-SHG) intensity is less than a nanometer. The results reported here question standard interpretations based on a single, averaged hyperpolarizability for all molecules at the interface. Not only the molecular first hyperpolarizability tensor significantly depends on the distance relative to the interface, but it is also correlated to the molecular orientation. Such hyperpolarizability fluctuations may impact the S-SHG intensity emitted by an aqueous interface.
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Affiliation(s)
- Guillaume Le Breton
- University of Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France.
| | - Oriane Bonhomme
- University of Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France.
| | - Pierre-François Brevet
- University of Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France.
| | - Emmanuel Benichou
- University of Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France.
| | - Claire Loison
- University of Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France.
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7
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Bouquiaux C, Castet F, Champagne B. Unravelling the Effects of Cholesterol on the Second-Order Nonlinear Optical Responses of Di-8-ANEPPS Dye Embedded in Phosphatidylcholine Lipid Bilayers. J Phys Chem B 2021; 125:10195-10212. [PMID: 34491062 DOI: 10.1021/acs.jpcb.1c05630] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cholesterol is known for its role in maintaining the correct fluidity and rigidity of the animals cell membranes and thus their functions. Assessing the content and the role of cholesterol in lipid bilayers is therefore of crucial importance for a deeper understanding and control of membrane functioning. In this computational work, we investigate bilayers built from three types of glycerophospholipid phosphatidylcholine (PC) lipids, namely dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and dioleoylphosphatidylcholine (DOPC), and containing different amounts of cholesterol by analyzing the second-harmonic generation (SHG) nonlinear optical (NLO) response of a probe molecule, di-8-ANEPPS, inserted into the membranes. This molecular property presents the advantage to be specific to interfacial regions such as lipid bilayers. To unravel these effects, Molecular Dynamics (MD) simulations have been performed on both DPPC and DOPC lipids by varying the cholesterol mole fraction (from 0 to 0.66), while POPC was only considered as a pure bilayer. In the case of the structural properties of the bilayers, all the analyses converge toward the same conclusion: as the mole fraction of cholesterol increases, the systems become more rigid, confirming the condensing effect of cholesterol. In addition, the chromophore is progressively more aligned with respect to the normal to the bilayer. On the contrary, addition of unsaturation disorders the lipid bilayers, with barely no impact on the alignment of the chromophore. Then, using the frames obtained from the MD simulations, the first hyperpolarizability β of the dye in its environment has been computed at the TDDFT level. On the one hand, the addition of cholesterol induces a progressive increase of the diagonal component the β tensor parallel to the bilayer normal. On the other hand, larger β values have been calculated for the unsaturated than for the saturated lipid systems. In summary, this study illustrates the relationship between the composition and structure of the bilayers and the NLO responses of the embedded dye.
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Affiliation(s)
- Charlotte Bouquiaux
- Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium
| | - Frédéric Castet
- , Institut des Sciences Moléculaires, UMR 5255 CNRS, University of Bordeaux, cours de la Libération 351, F-33405 Talence Cedex, France
| | - Benoît Champagne
- Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium
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8
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Hornum M, Kongsted J, Reinholdt P. Computational and photophysical characterization of a Laurdan malononitrile derivative. Phys Chem Chem Phys 2021; 23:9139-9146. [PMID: 33885105 DOI: 10.1039/d1cp00831e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The malononitrile group is considered one of the strongest natural electron-withdrawing groups in a chemist's arsenal. However, surprisingly little is known about how this group functions in push-pull fluorophores. In a recent computational study, we reported that replacing the ketone group of the traditional push-pull dye Laurdan with a malononitrile group significantly improves the optical properties while retaining the membrane behavior of the parent molecule Laurdan. Motivated by these results, we report here the synthesis and photophysical characterization of the said compound, 6-(1-undecyl-2,2-dicyanovinyl)-N,N-dimethyl-2-naphthylamine (CN-Laurdan). To our surprise, this new CN-Laurdan probe is found to be much less bright than the parent Laurdan due to a large drop in the fluorescence quantum yield. Using computational methods, we determine that the origin of this low quantum yield is related to the existence of a non-radiative decay pathway related to a rotation of the malononitrile moiety, suggesting that the molecule could nonetheless function very well as a molecular rotor. We confirm experimentally that CN-Laurdan functions as a molecular rotor by measuring the quantum yield in methanol/glycerol mixtures of increasing viscosity. Specifically, we found a consistent increase in the quantum yield across the entire range of tested viscosities.
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Affiliation(s)
- Mick Hornum
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, Odense M DK-5230, Denmark.
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Kofod CS, Prioli S, Hornum M, Kongsted J, Reinholdt P. Computational Characterization of Novel Malononitrile Variants of Laurdan with Improved Photophysical Properties for Sensing in Membranes. J Phys Chem B 2020; 124:9526-9534. [PMID: 33074683 DOI: 10.1021/acs.jpcb.0c06011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescent probes are powerful tools for improving our understanding of cellular membranes and other complex biological environments. Using simulations, we gain atomistic and electronic insights into the effectiveness of the probes. In the current work, we have used various computational approaches to comprehensively investigate the properties of the fluorescent probe Laurdan and two Laurdan-like probes: AADAL and ECL. In addition, we propose the development of their corresponding novel malononitrile variants, which are computationally characterized herein. For the candidate probes, electronic structure calculations were used to rationalize their optical properties, including their ability for two-photon activation, and molecular dynamics simulations were used to unravel atomistic details of their functioning within lipid bilayers. While Laurdan, AADAL, and ECL were found to have very similar optical and membrane partitioning profiles, their malononitrile variants were found to show significantly improved optical properties, especially in regard to two-photon cross sections, and they appear to retain the desired membrane characteristics of the parent Laurdan molecule.
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Affiliation(s)
- Cecilie Søderlund Kofod
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Salvatore Prioli
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Mick Hornum
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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10
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Osella S, Knippenberg S. The influence of lipid membranes on fluorescent probes' optical properties. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183494. [PMID: 33129783 DOI: 10.1016/j.bbamem.2020.183494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Organic fluorophores embedded in lipid bilayers can nowadays be described by a multiscale computational approach. Combining different length and time scales, a full characterization of the probe localization and optical properties led to novel insight into the effect of the environments. SCOPE OF REVIEW Following an introduction on computational advancements, three relevant probes are reviewed that delineate how a multiscale approach can lead to novel insight into the probes' (non) linear optical properties. Attention is paid to the quality of the theoretical description of the optical techniques. MAJOR CONCLUSIONS Computation can assess a priori novel probes' optical properties and guide the analysis and interpretation of experimental data in novel studies. The properties can be used to gain information on the phase and condition of the surrounding biological environment. GENERAL SIGNIFICANCE Computation showed that a canonical view on some of the probes should be revisited and adapted.
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Affiliation(s)
- Silvio Osella
- Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland.
| | - Stefan Knippenberg
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic; Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden; Theoretical Physics, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium.
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11
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Osella S, Paloncýová M, Sahi M, Knippenberg S. Influence of Membrane Phase on the Optical Properties of DPH. Molecules 2020; 25:E4264. [PMID: 32957614 PMCID: PMC7570797 DOI: 10.3390/molecules25184264] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/05/2020] [Accepted: 09/14/2020] [Indexed: 11/24/2022] Open
Abstract
The fluorescent molecule diphenylhexatriene (DPH) has been often used in combination with fluorescence anisotropy measurements, yet little is known regarding the non-linear optical properties. In the current work, we focus on them and extend the application to fluorescence, while paying attention to the conformational versatility of DPH when it is embedded in different membrane phases. Extensive hybrid quantum mechanics/molecular mechanics calculations were performed to investigate the influence of the phase- and temperature-dependent lipid environment on the probe. Already, the transition dipole moments and one-photon absorption spectra obtained in the liquid ordered mixture of sphingomyelin (SM)-cholesterol (Chol) (2:1) differ largely from the ones calculated in the liquid disordered DOPC and solid gel DPPC membranes. Throughout the work, the molecular conformation in SM:Chol is found to differ from the other environments. The two-photon absorption spectra and the ones obtained by hyper-Rayleigh scattering depend strongly on the environment. Finally, a stringent comparison of the fluorescence anisotropy decay and the fluorescence lifetime confirm the use of DPH to gain information upon the surrounding lipids and lipid phases. DPH might thus open the possibility to detect and analyze different biological environments based on its absorption and emission properties.
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Affiliation(s)
- Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Markéta Paloncýová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic;
- Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden;
| | - Maryam Sahi
- Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden;
| | - Stefan Knippenberg
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic;
- Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden;
- Theory Lab, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
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12
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Filipe HAL, Moreno MJ, Loura LMS. The Secret Lives of Fluorescent Membrane Probes as Revealed by Molecular Dynamics Simulations. Molecules 2020; 25:E3424. [PMID: 32731549 PMCID: PMC7435664 DOI: 10.3390/molecules25153424] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/23/2020] [Accepted: 07/25/2020] [Indexed: 12/15/2022] Open
Abstract
Fluorescent probes have been employed for more than half a century to study the structure and dynamics of model and biological membranes, using spectroscopic and/or microscopic experimental approaches. While their utilization has led to tremendous progress in our knowledge of membrane biophysics and physiology, in some respects the behavior of bilayer-inserted membrane probes has long remained inscrutable. The location, orientation and interaction of fluorophores with lipid and/or water molecules are often not well known, and they are crucial for understanding what the probe is actually reporting. Moreover, because the probe is an extraneous inclusion, it may perturb the properties of the host membrane system, altering the very properties it is supposed to measure. For these reasons, the need for independent methodologies to assess the behavior of bilayer-inserted fluorescence probes has been recognized for a long time. Because of recent improvements in computational tools, molecular dynamics (MD) simulations have become a popular means of obtaining this important information. The present review addresses MD studies of all major classes of fluorescent membrane probes, focusing in the period between 2011 and 2020, during which such work has undergone a dramatic surge in both the number of studies and the variety of probes and properties accessed.
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Affiliation(s)
- Hugo A. L. Filipe
- Chemistry Department, Coimbra Chemistry Center, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal;
| | - Maria João Moreno
- Coimbra Chemistry Center and CNC—Center for Neuroscience and Cell Biology, Chemistry Department, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal;
| | - Luís M. S. Loura
- Coimbra Chemistry Center and CNC—Center for Neuroscience and Cell Biology, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
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13
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Bouquiaux C, Tonnelé C, Castet F, Champagne B. Second-Order Nonlinear Optical Properties of an Amphiphilic Dye Embedded in a Lipid Bilayer. A Combined Molecular Dynamics–Quantum Chemistry Study. J Phys Chem B 2020; 124:2101-2109. [DOI: 10.1021/acs.jpcb.9b10988] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Charlotte Bouquiaux
- Theoretical Chemistry Laboratory, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, B-5000 Namur, Belgium
| | - Claire Tonnelé
- University of Bordeaux, Institut des Sciences Moléculaires, UMR 5255 CNRS, Cours de la Libération 351, F-33405 Talence Cedex, France
| | - Frédéric Castet
- University of Bordeaux, Institut des Sciences Moléculaires, UMR 5255 CNRS, Cours de la Libération 351, F-33405 Talence Cedex, France
| | - Benoît Champagne
- Theoretical Chemistry Laboratory, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, B-5000 Namur, Belgium
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14
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Paloncýová M, Aniander G, Larsson E, Knippenberg S. Cyanine dyes with tail length asymmetry enhance photoselection: A multiscale study on DiD probes in a liquid disordered membrane. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 224:117329. [PMID: 31326855 DOI: 10.1016/j.saa.2019.117329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 06/10/2023]
Abstract
Visualization of membrane domains like lipid rafts in natural or artificial membranes is a crucial task for cell biology. For this purpose, fluorescence microscopy is often used. Since fluorescing probes in lipid membranes partition specifically in e.g. local liquid disordered or liquid ordered environments, the consequent changes in their orientation and location are both theoretically and experimentally of interest. Here we focused on a liquid disordered membrane phase and performed molecular dynamics (MD) simulations of the indocarbocyanine DiD probes by varying the length of the attached alkyl tails and also the length of the cyanine backbone. From the probed compounds in a DOPC lipid bilayer at ambient temperature, a varying orientation of the transition dipole moment was observed, which is crucial for fluorescence microscopy and which, through photoselection, was found to be surprisingly more effective for asymmetric probes than for the symmetric ones. Furthermore, we observed that the orientation of the probes was dependent on the tail length; with the methyls or propyls attached, DiD oriented with its tails facing the water, contrary to the ones with longer tails. With advanced hybrid QM/MM calculations we show that the different local environment for differently oriented probes affected the one-photon absorption spectra, that was blue-shifted for the short-tailed DiD with respect to the DiDs with longer tails. We show here that the presented probes can be successfully used for fluorescence microscopy and we believe that the described properties bring further insight for the experimental use of these probes.
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Affiliation(s)
- Markéta Paloncýová
- Department of Theoretical Chemistry and Biology, KTH Royal Institute of Technology, Stockholm, Sweden; Biomedical Research Institute, Hasselt University, Agoralaan Building C, 3590 Diepenbeek, Belgium
| | - Gustav Aniander
- Department of Theoretical Chemistry and Biology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Emma Larsson
- Department of Theoretical Chemistry and Biology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Stefan Knippenberg
- Department of Theoretical Chemistry and Biology, KTH Royal Institute of Technology, Stockholm, Sweden; Biomedical Research Institute, Hasselt University, Agoralaan Building C, 3590 Diepenbeek, Belgium; RCPTM, Department of Physical Chemistry, Fac. Sciences, Palacký University, Olomouc, Czech Republic; Research group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
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15
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Osella S, Knippenberg S. Laurdan as a Molecular Rotor in Biological Environments. ACS APPLIED BIO MATERIALS 2019; 2:5769-5778. [DOI: 10.1021/acsabm.9b00789] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Stefan Knippenberg
- RCPTM, Department of Physical Chemistry, Fac. Sciences, Palacký University, 771 46 Olomouc, Czech Republic
- Theoretical Physics, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
- Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden
- Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
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16
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Osella S, Smisdom N, Ameloot M, Knippenberg S. Conformational Changes as Driving Force for Phase Recognition: The Case of Laurdan. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11471-11481. [PMID: 31403301 DOI: 10.1021/acs.langmuir.9b01840] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The development of a universal probe to assess the phase of a lipid membrane is one of the most ambitious goals for fluorescence spectroscopy. The ability of a well-known molecule as Laurdan to reach this aim is here exploited as the behavior of the probe is fully characterized in a dipalmitoylphosphatidylcholine (DPPC) solid gel (So) phase by means of molecular dynamics simulations. Laurdan can take two conformations, depending on whether the carbonyl oxygen points toward the β-position of the naphthalene core (Conf-I) or to the α-position (Conf-II). We observe that Conf-I has an elongated form in this environment, whereas Conf-II takes an L-shape. Interestingly, our theoretical calculations show that these two conformations behave in an opposite way from what is reported in the literature for a DPPC membrane in a liquid disordered (Ld) phase, where Conf-I assumes an L-shape and Conf-II is elongated. Moreover, our results show that in DPPC (So) no intermixing between the conformations is present, whereas it has been seen in a fluid environment such as DOPC (Ld). Through a careful analysis of angle distributions and by means of the rotational autocorrelation function, we predict that the two conformers of Laurdan behave differently in different membrane environments.
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Affiliation(s)
- Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies , University of Warsaw , Banacha 2C , 02-097 Warsaw , Poland
| | - Nick Smisdom
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
| | - Marcel Ameloot
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
| | - Stefan Knippenberg
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
- Department of Theoretical Chemistry and Biology, School of Biotechnology , Royal Institute of Technology , SE-10691 Stockholm , Sweden
- RCPTM, Department of Physical Chemistry, Fac. Sciences , Palacký University , 771 46 Olomouc , Czech Republic
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17
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Osella S, Di Meo F, Murugan NA, Fabre G, Ameloot M, Trouillas P, Knippenberg S. Combining (Non)linear Optical and Fluorescence Analysis of DiD To Enhance Lipid Phase Recognition. J Chem Theory Comput 2018; 14:5350-5359. [DOI: 10.1021/acs.jctc.8b00553] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Silvio Osella
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
- Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Florent Di Meo
- Faculty of Pharmacy, UMR 1248 INSERM, Limoges University, 2 rue du Docteur Marcland, 87025 Limoges Cedex, France
| | - N. Arul Murugan
- Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Gabin Fabre
- LCSN-EA1069, Faculty of Pharmacy, Limoges University, 2, rue du Dr. Marcland, 87025 Limoges Cedex, France
| | - Marcel Ameloot
- Biomedical Research Institute, Hasselt University, B-3590, Diepenbeek, Belgium
| | - Patrick Trouillas
- Faculty of Pharmacy, UMR 1248 INSERM, Limoges University, 2 rue du Docteur Marcland, 87025 Limoges Cedex, France
- Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Stefan Knippenberg
- Department of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, SE-10691 Stockholm, Sweden
- Biomedical Research Institute, Hasselt University, B-3590, Diepenbeek, Belgium
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18
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Knippenberg S, Fabre G, Osella S, Di Meo F, Paloncýová M, Ameloot M, Trouillas P. Atomistic Picture of Fluorescent Probes with Hydrocarbon Tails in Lipid Bilayer Membranes: An Investigation of Selective Affinities and Fluorescent Anisotropies in Different Environmental Phases. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9072-9084. [PMID: 29983063 DOI: 10.1021/acs.langmuir.8b01164] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
By reverting to spectroscopy, changes in the biological environment of a fluorescent probe can be monitored and the presence of various phases of the surrounding lipid bilayer membranes can be detected. However, it is currently not always clear in which phase the probe resides. The well-known orange 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbo-cyanine perchlorate (DiI-C18(5)) fluorophore, for instance, and the new, blue BODIPY (4,4-difluoro-4-bora-3 a,4 a-diaza- s-indacene) derivative were experimentally seen to target and highlight identical parts of giant unilamellar vesicles of various compositions, comprising mixtures of dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), sphingomyelin (SM), and cholesterol (Chol). However, it was not clear which of the coexisting membrane phases were visualized (Bacalum et al., Langmuir. 2016, 32, 3495). The present study addresses this issue by utilizing large-scale molecular dynamics simulations and the z-constraint method, which allows evaluating Gibbs free-energy profiles. The current calculations give an indication why, at room temperature, both BODIPY and DiI-C18(5) probes prefer the gel (So) phase in DOPC/DPPC (2:3 molar ratio) and the liquid-ordered (Lo) phase in DOPC/SM/Chol (1:2:1 molar ratio) mixtures. This study highlights the important differences in orientation and location and therefore in efficiency between the probes when they are used in fluorescence microscopy to screen various lipid bilayer membrane phases. Dependent on the lipid composition, the angle between the transition-state dipole moments of both probes and the normal to the membrane is found to deviate clearly from 90°. It is seen that the DiI-C18(5) probe is located in the headgroup region of the SM/Chol mixture, in close contact with water molecules. A fluorescence anisotropy study also indicates that DiI-C18(5) gives rise to a distinctive behavior in the SM/Chol membrane compared to the other considered membranes. The latter behavior has not been seen for the studied BODIPY probe, which is located deeper in the membrane.
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Affiliation(s)
- S Knippenberg
- Department of Theoretical Chemistry and Biology , KTH Royal Institute of Technology , Roslagstullsbacken 15 , S-106 91 Stockholm , Sweden
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
| | - G Fabre
- LCSN-EA1069, Faculty of Pharmacy , Limoges University , 2 rue du Dr. Marcland , 87025 Limoges Cedex , France
| | - S Osella
- Centre of New Technologies , University of Warsaw , Banacha 2C , 02-097 Warsaw , Poland
| | - F Di Meo
- Faculty of Pharmacy , INSERM UMR 1248, Limoges University , 2 rue du Docteur Marcland , 87025 Limoges Cedex , France
| | - M Paloncýová
- Department of Theoretical Chemistry and Biology , KTH Royal Institute of Technology , Roslagstullsbacken 15 , S-106 91 Stockholm , Sweden
| | - M Ameloot
- Biomedical Research Institute , Hasselt University , Agoralaan Building C , 3590 Diepenbeek , Belgium
| | - P Trouillas
- Faculty of Pharmacy , INSERM UMR 1248, Limoges University , 2 rue du Docteur Marcland , 87025 Limoges Cedex , France
- Centre of Advanced Technologies and Materials, Faculty of Science , Palacký University , tř. 17 listopadu 12 , 771 46 Olomouc , Czech Republic
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19
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Wasif Baig M, Pederzoli M, Jurkiewicz P, Cwiklik L, Pittner J. Orientation of Laurdan in Phospholipid Bilayers Influences Its Fluorescence: Quantum Mechanics and Classical Molecular Dynamics Study. Molecules 2018; 23:molecules23071707. [PMID: 30011800 PMCID: PMC6100051 DOI: 10.3390/molecules23071707] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/09/2018] [Accepted: 07/12/2018] [Indexed: 11/30/2022] Open
Abstract
Fluidity of lipid membranes is known to play an important role in the functioning of living organisms. The fluorescent probe Laurdan embedded in a lipid membrane is typically used to assess the fluidity state of lipid bilayers by utilizing the sensitivity of Laurdan emission to the properties of its lipid environment. In particular, Laurdan fluorescence is sensitive to gel vs liquid–crystalline phases of lipids, which is demonstrated in different emission of the dye in these two phases. Still, the exact mechanism of the environment effects on Laurdan emission is not understood. Herein, we utilize dipalmitoylphosphatidylcholine (DPPC) and dioleoylphosphatidylcholine (DOPC) lipid bilayers, which at room temperature represent gel and liquid–crystalline phases, respectively. We simulate absorption and emission spectra of Laurdan in both DOPC and DPPC bilayers with quantum chemical and classical molecular dynamics methods. We demonstrate that Laurdan is incorporated in heterogeneous fashion in both DOPC and DPPC bilayers, and that its fluorescence depends on the details of this embedding.
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Affiliation(s)
- Mirza Wasif Baig
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
- Faculty of Science, Department of Physical and Macromolecular Chemistry, Charles University in Prague, Hlavova 8, 12840 Prague, Czech Republic.
| | - Marek Pederzoli
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
- Faculty of Science, Department of Physical and Macromolecular Chemistry, Charles University in Prague, Hlavova 8, 12840 Prague, Czech Republic.
| | - Piotr Jurkiewicz
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
| | - Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovonám 2, 16610 Prague, Czech Republic.
| | - Jiri Pittner
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic.
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20
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Slenders E, Seneca S, Pramanik SK, Smisdom N, Adriaensens P, vandeVen M, Ethirajan A, Ameloot M. Dynamics of the phospholipid shell of microbubbles: a fluorescence photoselection and spectral phasor approach. Chem Commun (Camb) 2018; 54:4854-4857. [DOI: 10.1039/c8cc01012a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The lipid organization of microbubbles is important in many applications.
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Affiliation(s)
- Eli Slenders
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
| | - Senne Seneca
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Sumit Kumar Pramanik
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Nick Smisdom
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
| | - Peter Adriaensens
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Martin vandeVen
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
| | - Anitha Ethirajan
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Marcel Ameloot
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
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21
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Osella S, Knippenberg S. Triggering On/Off States of Photoswitchable Probes in Biological Environments. J Am Chem Soc 2017; 139:4418-4428. [DOI: 10.1021/jacs.6b13024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Silvio Osella
- Division of Theoretical Chemistry
and Biology, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Stefan Knippenberg
- Division of Theoretical Chemistry
and Biology, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden
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