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Feuk H, Nilsson S, Richter M. Temperature resolved decay time components of Mg 4FGeO 6:Mn using the maximum entropy method. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:034901. [PMID: 37012790 DOI: 10.1063/5.0141346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/13/2023] [Indexed: 06/19/2023]
Abstract
A thermographic phosphor's decay time distribution over its temperature-sensitive range was retrieved with the Maximum Entropy Method (MEM). A decay time distribution consists of a range of decay times, each with an associated weighting for the decay time component's prevalence in the analyzed decay curve. With the MEM, significant decay time contributions of a decay curve have high weighting and are therefore found as peaks in the decay time distribution, where the width and peak value are correlated with the relative weight of the decay time components. These peaks in the decay time distribution give increased insight into a phosphor's lifetime behavior, which often cannot accurately be represented by a single or even two decay time components. The changes in the location of peaks in the decay time distribution with temperature can be used for thermometry, and this method has the benefit of being less sensitive to the multi-exponentiality of phosphor decay than mono-exponential decay time fitting. The method also resolves the underlying decay components with no assumptions of the number of significant decay time components. Initially, when the decay time distribution of Mg4FGeO6:Mn was captured, the collected decay included decaying luminescence from the alumina oxide tube in the tube furnace. Therefore, a second calibration was performed where the luminescence from the alumina oxide tube was minimized. These two calibration datasets were used to demonstrate that the MEM could characterize decays from two separate sources simultaneously.
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Affiliation(s)
- Henrik Feuk
- Combustion Physics, Department of Physics, Lund University, Box 118, 221 00 Lund, Sweden
| | - Sebastian Nilsson
- Combustion Physics, Department of Physics, Lund University, Box 118, 221 00 Lund, Sweden
| | - Mattias Richter
- Combustion Physics, Department of Physics, Lund University, Box 118, 221 00 Lund, Sweden
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Investigation of Molecular Diffusion at Block Copolymer Thin Films Using Maximum Entropy Method-Based Fluorescence Correlation Spectroscopy and Single Molecule Tracking. J Fluoresc 2022; 32:1779-1787. [PMID: 35689743 DOI: 10.1007/s10895-022-02975-6] [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: 04/07/2022] [Accepted: 05/27/2022] [Indexed: 10/18/2022]
Abstract
Fluorescence correlation spectroscopy (FCS) has been widely used to investigate molecular diffusion behavior in various samples. The use of the maximum entropy method (MEM) for FCS data analysis provides a unique means to determine multiple distinct diffusion coefficients without a priori assumption of their number. Comparison of the MEM-based FCS method (MEM-FCS) with another method will reveal its utility and advantage as an analytical tool to investigate diffusion dynamics. Herein, we measured diffusion of fluorescent probes doped into nanostructured thin films using MEM-FCS, and validated the results with single molecule tracking (SMT) data. The efficacy of the MEM code employed was first demonstrated by analyzing simulated FCS data for systems incorporating one and two diffusion modes with broadly distributed diffusion coefficients. The MEM analysis accurately afforded the number of distinct diffusion modes and their mean diffusion coefficients. These results contrasted with those obtained by fitting the simulated data to conventional two-component and anomalous diffusion models, which yielded inaccurate estimates of the diffusion coefficients. Subsequently, the MEM analysis was applied to FCS data acquired from hydrophilic dye molecules incorporated into microphase-separated polystyrene-block-poly(ethylene oxide) (PS-b-PEO) thin films characterized under a water-saturated N2 atmosphere. The MEM analysis revealed distinct fast and slow diffusion components attributable to molecules diffusing on the film surface and inside the film, respectively. SMT studies of the same materials yielded trajectories for mobile molecules that appear to follow the curved PEO microdomains. Diffusion coefficients obtained from the SMT data were consistent with those obtained for the slow diffusion component detected by MEM-FCS. These results highlight the utility of MEM-FCS and SMT for gaining complementary information on molecular diffusion processes in heterogeneous material systems.
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Pominova D, Romanishkin I, Proydakova V, Kuznetsov S, Grachev P, Ryabova A, Tabachkova NY, Fedorov P, Loschenov V. Study of synthesis temperature effect on β-NaGdF 4: Yb 3+, Er 3+upconversion luminescence efficiency and decay time using maximum entropy method. Methods Appl Fluoresc 2022; 10. [PMID: 35263723 DOI: 10.1088/2050-6120/ac5bdc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/09/2022] [Indexed: 11/11/2022]
Abstract
Upconversion materials have several advantages for many applications due to their great potential in converting infrared light to visible. For practical use, it is necessary to achieve high intensity of UC luminescence, so the studies of the optimal synthesis parameters for upconversion nanoparticles are still going on. In the present work, we analyzed the synthesis temperature effect on the efficiency and luminescence decay of β-NaGd0.78Yb0.20Er0.02F4 (15-25 nm) upconversion nanoparticles with hexagonal crystal structure synthesized by anhydrous solvothermal technique. The synthesis temperature was varied in the 290-320°C range. The synthesis temperature was shown to have a significant influence on the upconversion luminescence efficiency and decay time. The coherent scattering domain linearly depended on the synthesis temperature and was in the range 13.1-22.3 nm, while the efficiency of the upconversion luminescence increases exponentially from 0.02 to 0.10% under 1 W/cm2 excitation. For a fundamental analysis of the reasons for the upconversion luminescence intensity dependence on the synthesis temperature, it was proposed to use the maximum entropy method for luminescence decay kinetics processing. This method does not require a preliminary setting of the number of exponents and, due to this, makes it possible to estimate additional components in the luminescence decay kinetics, which are attributed to different populations of rare-earth ions in different conditions. Two components in the green luminescence and one component in the red luminescence decay kinetics were revealed for nanoparticles prepared at 290-300°C. An intense short and a weak long component in green luminescence decay kinetics could be associated with two different populations of ions in the surface quenching layer and the crystal core volume. With an increase in the synthesis temperature, the second component disappears, and the decay time increases due to an increase in the number of ions in the crystal core volume and a more uniform distribution of dopants.
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Affiliation(s)
- Daria Pominova
- Prokhorov General Physics Institute RAS, Vavilova str., 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Igor Romanishkin
- Prokhorov General Physics Institute RAS, Vavilova str 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Vera Proydakova
- Prokhorov General Physics Institute RAS, Vavilova str 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Sergei Kuznetsov
- Prokhorov General Physics Institute RAS, Vavilova str 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Pavel Grachev
- Prokhorov General Physics Institute RAS, Vavilova str 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Anastasia Ryabova
- Prokhorov General Physics Institute RAS, Vavilova str 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Natalie Yu Tabachkova
- Prokhorov General Physics Institute RAS, Vavilova str. 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Pavel Fedorov
- Prokhorov General Physics Institute RAS, Vavilova str 38, Moskva, 119991, RUSSIAN FEDERATION
| | - Victor Loschenov
- Prokhorov General Physics Institute RAS, Vavilova str 38, Moskva, 119991, RUSSIAN FEDERATION
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Syed A, Mishra S, Jayanty S. 7,7-bis(N, N-diethylethylenediamino)-8,8-dicyanoquinodimethane: Effect of Ethyl Moiety on the Photophysical Property besides Thermal Stability. J Fluoresc 2021; 32:115-124. [PMID: 34599730 DOI: 10.1007/s10895-021-02830-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 09/21/2021] [Indexed: 11/26/2022]
Abstract
Tetracyanoquinodimethane (TCNQ) on reaction with primary/secondary amines sequels in mono/di-substituted TCNQ adducts known as diaminodicyanoquinodimethanes (DADQ's) possessing astounding optical or non-linear optical characteristics. Crucially, the subtle choice of amine contributes to the outcome of molecular material aspects. Herein, we present a comprehensive investigation of 7,7-bis(N,N-diethylethylenediamino)-8,8-dicyanoquinodimethane (BDEDDQ); manifesting the impact of ethyl group (existing on the di-substituted nitrogen of N,N-diethylethylenediamine (DEED)); on the crystal structure, optical property and thermal stability. Crystallography study revealed supramolecular self-assemblies among molecular dipoles emanating fluorescence enhancement in the solid state compared to solutions. Quantum yields were primarily ~0.2 to 0.4% in solutions and ~56% in the solid. Stokes shift was noticed to be more in solutions (~90 nm) than solid (~67 nm), suggesting excess vibrational relaxations in solutions. Differential scanning calorimetry revealed ~182 °C as the melting temperature. The heat capacity of solid was found to be 5.03 mJs-1. Thermogravimetric analysis conveyed single stage decomposition process initiated by the two amine side chains. Scanning electron microscopy of films prepared by drop casting solutions imparted divergent morphological features, due to different rates of evaporation accompanied by varied growth kinetics. Accordingly, in this paper we have demonstrated the utilization of simple N,N-diethylethylenediamine (DEED) to successfully generate a noteworthy blue emissive molecular material exhibiting semiconducting feature besides reasonable thermal stability.
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Affiliation(s)
- Anwarhussaini Syed
- Department of Chemistry, Birla Institute of Technology and Science-Hyderabad Campus, Medchal Dist. Hyderabad - 500078, Telangana State, Jawaharnagar, Shameerpet, Kapra Mandal, India
| | - Sabyashachi Mishra
- Department of Chemistry, Kharagpur and Centre for Computational and Data Sciences, Indian Institute of Technology, Indian Institute of Technology Kharagpur, 721302, Kharagpur, West Bengal, India
| | - Subbalakshmi Jayanty
- Department of Chemistry, Birla Institute of Technology and Science-Hyderabad Campus, Medchal Dist. Hyderabad - 500078, Telangana State, Jawaharnagar, Shameerpet, Kapra Mandal, India.
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Romei MG, Lin CY, Mathews II, Boxer SG. Electrostatic control of photoisomerization pathways in proteins. Science 2020; 367:76-79. [PMID: 31896714 DOI: 10.1126/science.aax1898] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/04/2019] [Accepted: 10/31/2019] [Indexed: 12/23/2022]
Abstract
Rotation around a specific bond after photoexcitation is central to vision and emerging opportunities in optogenetics, super-resolution microscopy, and photoactive molecular devices. Competing roles for steric and electrostatic effects that govern bond-specific photoisomerization have been widely discussed, the latter originating from chromophore charge transfer upon excitation. We systematically altered the electrostatic properties of the green fluorescent protein chromophore in a photoswitchable variant, Dronpa2, using amber suppression to introduce electron-donating and electron-withdrawing groups to the phenolate ring. Through analysis of the absorption (color), fluorescence quantum yield, and energy barriers to ground- and excited-state isomerization, we evaluate the contributions of sterics and electrostatics quantitatively and demonstrate how electrostatic effects bias the pathway of chromophore photoisomerization, leading to a generalized framework to guide protein design.
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Affiliation(s)
- Matthew G Romei
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
| | - Chi-Yun Lin
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, Menlo Park, CA 94025, USA
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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Raghuraman H, Chatterjee S, Das A. Site-Directed Fluorescence Approaches for Dynamic Structural Biology of Membrane Peptides and Proteins. Front Mol Biosci 2019; 6:96. [PMID: 31608290 PMCID: PMC6774292 DOI: 10.3389/fmolb.2019.00096] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/11/2019] [Indexed: 12/31/2022] Open
Abstract
Membrane proteins mediate a number of cellular functions and are associated with several diseases and also play a crucial role in pathogenicity. Due to their importance in cellular structure and function, they are important drug targets for ~60% of drugs available in the market. Despite the technological advancement and recent successful outcomes in determining the high-resolution structural snapshot of membrane proteins, the mechanistic details underlining the complex functionalities of membrane proteins is least understood. This is largely due to lack of structural dynamics information pertaining to different functional states of membrane proteins in a membrane environment. Fluorescence spectroscopy is a widely used technique in the analysis of functionally-relevant structure and dynamics of membrane protein. This review is focused on various site-directed fluorescence (SDFL) approaches and their applications to explore structural information, conformational changes, hydration dynamics, and lipid-protein interactions of important classes of membrane proteins that include the pore-forming peptides/proteins, ion channels/transporters and G-protein coupled receptors.
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Affiliation(s)
- H. Raghuraman
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, Kolkata, India
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Esposito R, Delfino I, Portaccio M, Iannuzzi C, Lepore M. An insight into pH-induced changes in FAD conformational structure by means of time-resolved fluorescence and circular dichroism. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 48:395-403. [PMID: 31053922 DOI: 10.1007/s00249-019-01369-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/02/2019] [Accepted: 04/25/2019] [Indexed: 11/26/2022]
Abstract
Optical properties of flavin adenine dinucleotide (FAD) moiety are widely used nowadays for biotechnological applications. Given the fundamental role played by FAD, additional structural information about this enzymatic cofactor can be extremely useful in order to obtain a greater insight into its functional role in proteins. For this purpose, we have investigated FAD behaviour in aqueous solutions at different pH values by a novel approach based on the combined use of time-resolved fluorescence and circular dichroism spectroscopies. The results showed that pH strongly affects time-resolved fluorescence emission and the analysis allowed us to detect a three-component decay for FAD in aqueous solution with pH-depending lifetimes and relative amplitudes. Circular dichroism data were analyzed by a multi-Gaussian fitting procedure and the trends of properly chosen parameters confirmed pH-depending changes. The comparison between the results obtained by these two optical techniques allowed us to improve the significance of the outcome of circular dichroism. This combined approach may provide a useful tool for biotechnological investigation.
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Affiliation(s)
- Rosario Esposito
- Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione industriale, Università Federico II, P.le Tecchio 80, 80125, Naples, Italy
| | - Ines Delfino
- Dipartimento di Scienze Ecologiche e Biologiche, Università della Tuscia, Largo dell'Università snc, 01100, Viterbo, Italy.
| | - Marianna Portaccio
- Dipartimento di Medicina Sperimentale, Università della Campania "Luigi Vanvitelli", Via S.M. Costantinopoli 16, 80134, Naples, Italy
| | - Clara Iannuzzi
- Dipartimento di Medicina di Precisione, Università della Campania "Luigi Vanvitelli", Via L. De Crecchio 7, 80138, Naples, Italy
| | - Maria Lepore
- Dipartimento di Medicina Sperimentale, Università della Campania "Luigi Vanvitelli", Via S.M. Costantinopoli 16, 80134, Naples, Italy
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Connolly M, Arra A, Zvoda V, Steinbach PJ, Rice PA, Ansari A. Static Kinks or Flexible Hinges: Multiple Conformations of Bent DNA Bound to Integration Host Factor Revealed by Fluorescence Lifetime Measurements. J Phys Chem B 2018; 122:11519-11534. [DOI: 10.1021/acs.jpcb.8b07405] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mitchell Connolly
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Aline Arra
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Viktoriya Zvoda
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Peter J. Steinbach
- Center for Molecular Modeling, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Phoebe A. Rice
- Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, Illinois 60637, United States
| | - Anjum Ansari
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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9
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Thakare S, Stachelek P, Mula S, More AB, Chattopadhyay S, Ray AK, Sekar N, Ziessel R, Harriman A. Solvent-Driven Conformational Exchange for Amide-Linked Bichromophoric BODIPY Derivatives. Chemistry 2016; 22:14356-66. [DOI: 10.1002/chem.201602354] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Shrikant Thakare
- Department of Dyestuff Technology; Institute of Chemical Technology; Mumbai 400019 India
| | - Patrycja Stachelek
- Molecular Photonics Laboratory; School of Chemistry; Newcastle University; Bedson Building Newcastle upon Tyne NE1 7RU UK
| | - Soumyaditya Mula
- Bio-Organic Division; Bhabha Atomic Research Centre; Mumbai 400085 India
| | - Ankush B. More
- Department of Dyestuff Technology; Institute of Chemical Technology; Mumbai 400019 India
| | | | - Alok K. Ray
- Laser and Plasma Technology Division; Bhabha Atomic Research Centre; Mumbai 400085 India
| | - Nagaiyan Sekar
- Department of Dyestuff Technology; Institute of Chemical Technology; Mumbai 400019 India
| | - Raymond Ziessel
- Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA); Ecole Européenne de Chimie; Polymères et Matériaux; Université de Strasbourg; 25 rue Becquerel 67087 Strasbourg Cedex 02 France
| | - Anthony Harriman
- Molecular Photonics Laboratory; School of Chemistry; Newcastle University; Bedson Building Newcastle upon Tyne NE1 7RU UK
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