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Syryamina VN, Astvatsaturov DA, Dzuba SA, Chumakova NA. Glass-like behavior of intercalated organic solvents in graphite oxide detected by spin-probe EPR. Phys Chem Chem Phys 2023; 25:25720-25727. [PMID: 37721717 DOI: 10.1039/d3cp03253a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Membranes based on graphite oxide (GO) are promising materials for the separation of polar liquids and gases. Understanding the properties of solvents immersed in GO is important for the development of various technological applications. Here, the molecular motions of the TEMPO nitroxide spin probe in acetonitrile intercalated into the GO inter-plane space were studied using electron paramagnetic resonance (EPR), including its pulsed version, and electron spin echo (ESE). For a sample containing 75% acetonitrile relative to equilibrium sorption at room temperature, ESE-detected stochastic librations were observed for TEMPO molecules above 135 K. Since these librations are an inherent property of molecular glasses, this fact indicates that intercalated acetonitrile forms a two-dimensional glass state. Above 225 K, an acceleration of stochastic librations was observed, indicating the manifestation of a glass-like dynamical cross-over. Continuous wave (CW) EPR spectra of TEMPO showed the absence of overall tumbling motions in the entire investigated temperature range of up to 340 K, indicating that the intercalated acetonitrile does not behave as a bulk liquid (the melting point of acetonitrile is 229 K). Dynamical librations of TEMPO molecules detected by CW EPR were found to accelerate above 240 K.
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Affiliation(s)
- Victoria N Syryamina
- Voevodsky Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk, 630090, Russian Federation.
| | - Dmitry A Astvatsaturov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Science, Kosygin St. 4, Moscow, 119991, Russian Federation
- M.V. Lomonosov Moscow State University, Chemistry Department, Leninskiye Gory, 1/3, Moscow, 119991, Russian Federation
| | - Sergei A Dzuba
- Voevodsky Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk, 630090, Russian Federation.
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russian Federation
| | - Natalia A Chumakova
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Science, Kosygin St. 4, Moscow, 119991, Russian Federation
- M.V. Lomonosov Moscow State University, Chemistry Department, Leninskiye Gory, 1/3, Moscow, 119991, Russian Federation
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2
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Bakulina OD, Ivanov MY, Prikhod’ko SA, Adonin NY, Fedin MV. Effects of Zwitterions on Structural Anomalies in Ionic Liquid Glasses Studied by EPR. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2164. [PMID: 37570482 PMCID: PMC10420841 DOI: 10.3390/nano13152164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 07/22/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023]
Abstract
Ionic liquids (ILs) form a variety of nanostructures due to their amphiphilic nature. Recently, unusual structural phenomena have been found in glassy ILs near their glass transition temperatures; however, in all studied cases, IL cations and anions were in the form of separate moieties. In this work, we investigate for the first time such structural anomalies in zwitterionic IL glasses (ZILs), where the cation and anion are bound in a single molecule. Such binding reasonably restricts mutual diffusion of cations and anions, leading to modification of nano-ordering and character of structural anomalies in these glassy nanomaterials, as has been investigated using Electron Paramagnetic Resonance (EPR) spectroscopy. In particular, the occurrence of structural anomalies in ZIL glasses was revealed, and their characteristic temperatures were found to be higher compared to common ILs of a similar structure. Altogether, this work broadens the scope of structural anomalies in ionic liquid glasses and indicates new routes to tune their properties.
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Affiliation(s)
- Olga D. Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia;
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia;
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia;
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
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3
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Bakulina OD, Ivanov MY, Alimov DV, Prikhod’ko SA, Adonin NY, Fedin MV. Active Pharmaceutical Ingredient-Ionic Liquids (API-ILs): Nanostructure of the Glassy State Studied by Electron Paramagnetic Resonance Spectroscopy. Molecules 2022; 27:molecules27165117. [PMID: 36014356 PMCID: PMC9415235 DOI: 10.3390/molecules27165117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/22/2022] [Accepted: 08/02/2022] [Indexed: 12/02/2022] Open
Abstract
Active Pharmaceutical Ingredient-Ionic Liquids (API-ILs) draw increasing interest as a particular class of ILs that possess unusual physicochemical properties along with simultaneous potentials for pharmaceutical applications. Although nanostructuring phenomena were actively investigated in common ILs, their studies in API-ILs are scarce so far. In this work, using the complex methodology of Electron Paramagnetic Resonance (EPR) and dissolved spin probes, we investigate nanostructuring phenomena in a series of API-ILs: [Cnmim][Ibu], [Cnmim][Gly], and [Cnmim][Sal] with n = 2, 4, and 6, respectively. We reveal similar trends for API-ILs and common ILs, as well as peculiarities inherent to the studied API-ILs. Unusual behavior observed for [Cnmim][Ibu] has been assigned to the presence of a non-polar fragment in the [Ibu]− anion, which leads to the formation of more complex nanostructures around the radical compared to common ILs. Understanding general trends in the formation of such self-organized molecular structures is of fundamental interest and importance for applying API-ILs.
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Affiliation(s)
- Olga D. Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
- Correspondence: (M.Y.I.); (M.V.F.)
| | - Dmitriy V. Alimov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
- Correspondence: (M.Y.I.); (M.V.F.)
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4
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Low-temperature librations and dynamical transition in proteins at differing hydration levels. Biomol Concepts 2022; 13:81-88. [DOI: 10.1515/bmc-2022-0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 02/14/2022] [Indexed: 11/15/2022] Open
Abstract
Abstract
Hydration of water affects the dynamics and in turn the activity of biomacromolecules. We investigated the dependence of the librational oscillations and the dynamical transition on the hydrating conditions of two globular proteins with different structure and size, namely β-lactoglobulin (βLG) and human serum albumin (HSA), by spin-label electron paramagnetic resonance (EPR) in the temperature range of 120–270 K. The proteins were spin-labeled with 5-maleimide spin-label on free cysteins and prepared in the lyophilized state, at low (h = 0.12) and full (h = 2) hydration levels in buffer. The angular amplitudes of librations are small and almost temperature independent for both lyophilized proteins. Therefore, in these samples, the librational dynamics is restricted and the dynamical transition is absent. In the small and compact beta-structured βLG, the angular librational amplitudes increase with temperature and hydrating conditions, whereas hydration-independent librational oscillations whose amplitudes rise with temperature are recorded in the large and flexible alpha-structured HSA. Both βLG and HSA at low and fully hydration levels undergo the dynamical transition at about 230 K. The overall results indicate that protein librational dynamics is activated at the low hydration level h = 0.12 and highlight biophysical properties that are common to other biosamples at cryogenic temperatures.
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Aloi E, Bartucci R. Influence of hydration on segmental chain librations and dynamical transition in lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183805. [PMID: 34662568 DOI: 10.1016/j.bbamem.2021.183805] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/29/2021] [Accepted: 10/10/2021] [Indexed: 12/23/2022]
Abstract
Continuous wave electron paramagnetic resonance spectroscopy of chain-labeled phospholipids is used to investigate the effects of hydration on the librational oscillations and the dynamical transition of phospholipid membranes in the low-temperature range 120-270 K. Bilayers of dipalmitoylphostatidiycholine (DPPC) spin-labeled at the first acyl chain segments and at the methyl ends and prepared at full, low, and very low hydration are considered. The segmental mean-square angular amplitudes of librations, 〈α2〉, are larger in the bilayer interior than at the polar/apolar interface and larger in the fully and low hydrated than in the very low hydrated membranes. For chain segments at the beginning of the hydrocarbon region, 〈α2〉-values are markedly restricted and temperature independent in DPPC with the lowest water content, whereas they increase with temperature in the low and fully hydrated bilayers, particularly at the highest temperatures. For chain segments at the chain termini, the librational amplitudes increase progressively, first slowly and then more rapidly with temperature in bilayers at any level of hydration. From the temperature dependence of the mean-square librational amplitude, the dynamical transition is detected around 240 K at the polar/apolar interface in fully and low hydrated DPPC and at around 225 K at the inner hydrocarbon region for bilayers at any hydration condition. At the dynamical transition the bilayers cross low energy barriers of activation energy in the range 10-20 kJ/mol. The results highlight biophysical properties of DPPC bilayers at low-temperature and provide evidence of the effects of the hydration on the dynamical transition in bilayers.
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Affiliation(s)
- Erika Aloi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, (CS), Italy
| | - Rosa Bartucci
- Department of Chemistry and Chemical Technologies, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, (CS), Italy.
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6
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Probing Small-Angle Molecular Motions with EPR Spectroscopy: Dynamical Transition and Molecular Packing in Disordered Solids. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8020019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Disordered molecular solids present a rather broad class of substances of different origin—amorphous polymers, materials for photonics and optoelectronics, amorphous pharmaceutics, simple molecular glass formers, and others. Frozen biological media in many respects also may be referred to this class. Theoretical description of dynamics and structure of disordered solids still does not exist, and only some phenomenological models can be developed to explain results of particular experiments. Among different experimental approaches, electron paramagnetic resonance (EPR) applied to spin probes and labels also can deliver useful information. EPR allows probing small-angle orientational molecular motions (molecular librations), which intrinsically are inherent to all molecular solids. EPR is employed in its conventional continuous wave (CW) and pulsed—electron spin echo (ESE)—versions. CW EPR spectra are sensitive to dynamical librations of molecules while ESE probes stochastic molecular librations. In this review, different manifestations of small-angle motions in EPR of spin probes and labels are discussed. It is shown that CW-EPR-detected dynamical librations provide information on dynamical transition in these media, similar to that explored with neutron scattering, and ESE-detected stochastic librations allow elucidating some features of nanoscale molecular packing. The possible EPR applications are analyzed for gel-phase lipid bilayers, for biological membranes interacting with proteins, peptides and cryoprotectants, for supercooled ionic liquids (ILs) and supercooled deep eutectic solvents (DESs), for globular proteins and intrinsically disordered proteins (IDPs), and for some other molecular solids.
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7
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EPR study of nanostructuring in protic ionic liquids [PriNH3]NO3 and [BuNH3]NO3. Russ Chem Bull 2022. [DOI: 10.1007/s11172-021-3353-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Ivanov MY, Surovtsev NV, Fedin MV. Ionic liquid glasses: properties and applications. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Ivanov MY, Bakulina OD, Alimov DV, Prikhod'ko SA, Veber SL, Pylaeva S, Adonin NY, Fedin MV. Inherent heterogeneities and nanostructural anomalies in organic glasses revealed by EPR. NANOSCALE ADVANCES 2021; 3:4973-4978. [PMID: 36132341 PMCID: PMC9416887 DOI: 10.1039/d1na00452b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 07/22/2021] [Indexed: 06/15/2023]
Abstract
Intriguing heterogeneities and nanostructural reorganizations of glassy ionic liquids (ILs) have recently been found using electron paramagnetic resonance (EPR) spectroscopy. Alkyl chains of IL cations play the key role in such phenomena and govern the anomalous temperature dependence of local density and molecular mobility. In this paper we evidence and study similar manifestations in a variety of common non-IL glasses, which also contain molecules with alkyl chains. A series of phthalates clearly demonstrates very similar behavior to imidazolium-based ILs with the same length of alkyl chain. Glasses of alkyl alcohols and alkyl benzenes show only some similarities to the corresponding ILs, mainly due to a lower glass transition temperature hindering the development of the anomaly. Therefore, we demonstrate the general nature and broad scope of nanoscale structural anomalies in organic glasses based on alkyl-chain compounds. The 'roadmap' for their occurrence is provided, which aids in understanding and future applications of these anomalous nanoheterogeneities.
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Affiliation(s)
- Mikhail Yu Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
| | - Olga D Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
- Novosibirsk State University Pirogova Street 2 630090 Novosibirsk Russia
| | - Dmitriy V Alimov
- Novosibirsk State University Pirogova Street 2 630090 Novosibirsk Russia
| | - Sergey A Prikhod'ko
- Boreskov Institute of Catalysis SB RAS Lavrentiev Avenue 5 630090 Novosibirsk Russia
| | - Sergey L Veber
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
| | - Svetlana Pylaeva
- Universität Paderborn Warburger Str. 100 33098 Paderborn Germany
| | - Nicolay Yu Adonin
- Boreskov Institute of Catalysis SB RAS Lavrentiev Avenue 5 630090 Novosibirsk Russia
| | - Matvey V Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
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10
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Ivanov MY, Poryvaev AS, Polyukhov DM, Prikhod'ko SA, Adonin NY, Fedin MV. Nanoconfinement effects on structural anomalies in imidazolium ionic liquids. NANOSCALE 2020; 12:23480-23487. [PMID: 33174581 DOI: 10.1039/d0nr06961b] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Imidazolium Ionic Liquids (ILs) have been found to exhibit unusual nanostructuring behavior below their glass transition temperatures (Tg), which is ascribed to rearrangements in nonpolar domains formed by segregated alkyl chains. However, the dimensions required for such highly cooperative bulk phenomena are still unknown. In this work, we for the first time, investigate the effect of nanoconfinement on structural anomalies in imidazolium ILs. For this purpose, a series of ILs were embedded into the cavities of metal-organic framework (MOF) ZIF-8 and investigated using spin probes and Electron Paramagnetic Resonance (EPR) spectroscopy. The unusual nanostructuring near Tg, previously known for bulk ILs, was also observed for such nanoconfined ILs, and the amplitude of the anomaly was found to be dependent on the structure of the IL, thus showing the effects of molecular packing inside the MOF cavity. The first observation of structural anomalies in nanoconfined ILs opens perspectives for designing smart materials exhibiting these phenomena, and engaging MOFs as platforms creates the basis for potential applications of such functionalities.
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Affiliation(s)
- Mikhail Yu Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia.
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11
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Bakulina OD, Ivanov MY, Prikhod'ko SA, Pylaeva S, Zaytseva IV, Surovtsev NV, Adonin NY, Fedin MV. Nanocage formation and structural anomalies in imidazolium ionic liquid glasses governed by alkyl chains of cations. NANOSCALE 2020; 12:19982-19991. [PMID: 32996529 DOI: 10.1039/d0nr06065h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Intriguing nanostructuring anomalies have been recently observed in imidazolium ionic liquids (ILs) near their glass transition points, where local density around a nanocaged solute progressively grows up with temperature. Herewith, we for the first time demonstrate experimentally and theoretically, that these anomalies are governed by alkyl chains of cations and crucially depend on their length. Electron Paramagnetic Resonance (EPR) spectroscopy on a series of ILs [Cnmim]BF4 (n = 0-12) shows that only the chains with n = 3-10 favor anomaly. Moreover, remarkable even vs. odd n peculiarities were systematically observed. Finally, similar anomaly was for the first time observed for a non-IL glass of dibutyl phthalate, which structurally mimics cations of imidazolium ILs. Therefore, such anomalous density behavior in a glassy state nanocage goes far beyond ILs and proves to be a more general phenomenon, which can be structurally tuned and rationally adjusted for various potential applications in nanoscale materials.
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Affiliation(s)
- Olga D Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia.
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12
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Ivanov MY, Prikhod’ko SA, Adonin NY, Fedin MV. Structural Anomalies in Binary Mixtures of Ionic Liquid [Bmim]BF4 with Water Studied by EPR. J Phys Chem B 2019; 123:9956-9962. [DOI: 10.1021/acs.jpcb.9b08933] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
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13
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Aloi E, Guzzi R, Bartucci R. Unsaturated lipid bilayers at cryogenic temperature: librational dynamics of chain-labeled lipids from pulsed and CW-EPR. Phys Chem Chem Phys 2019; 21:18699-18705. [PMID: 31423504 DOI: 10.1039/c9cp03318a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fully hydrated bilayers of monounsaturated palmitoyloleoylphosphatidylcholine (POPC) and diunsaturated dioleoylphosphatidylcholine (DOPC) lipids have low main phase transition temperatures (271 K for POPC and 253 K for DOPC). Two-pulse echo detected spectra, combined with continuous wave electron paramagnetic resonance spectroscopy, are employed to study the low-temperature lamellar phases of the POPC and DOPC unsaturated bilayers that are usually studied in the fluid state. Phosphatidylcholine spin-labeled at C-5 and C-16 carbon atom positions along the acyl chain were used and the temperature varied over the range 77-270 K. Segmental chain librational oscillations of small amplitude and with correlation time in the subnanosecond to nanosecond range are found in both membranes. The mean-square angular amplitude, α2, of librations increases with temperature, is larger close to the bilayer midplane than close to the first acyl chain segments, and is larger in diunsaturated than in monounsaturated bilayers. In the inner hydrocarbon region of both lipid matrices, α2 increases first slowly and linearly with temperature and then more rapidly, and a dynamical transition is detected in the range 190-210 K. Compared to dipalmitoylphosphatidylcholine bilayers of fully saturated symmetric chain lipids, the presence of double bonds in the acyl chain enhances the intensity of librational motion which is characterized by larger angular variations at the terminal methyl ends. These findings highlight biophysical properties of unsaturated bilayers in the frozen state, including a detailed characterization of segmental chain dynamics and the evidence of a dynamical transition that appears to be a generic feature in hydrated macromolecular systems. These results can also be relevant in regulating membrane physical properties and function at higher physiological temperatures.
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Affiliation(s)
- Erika Aloi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy
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14
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Ivanov MY, Fedin MV. Nanoscale heterogeneities in ionic liquids: insights from EPR of spin probes. MENDELEEV COMMUNICATIONS 2018. [DOI: 10.1016/j.mencom.2018.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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15
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Kuzhelev AA, Krumkacheva OA, Ivanov MY, Prikhod'ko SA, Adonin NY, Tormyshev VM, Bowman MK, Fedin MV, Bagryanskaya EG. Pulse EPR of Triarylmethyl Probes: A New Approach for the Investigation of Molecular Motions in Soft Matter. J Phys Chem B 2018; 122:8624-8630. [PMID: 30137993 DOI: 10.1021/acs.jpcb.8b07714] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Triarylmethyl (TAM) radicals have become widely used free radicals in the past few years. Their electron spins have long relaxation times and narrow electron paramagnetic resonance (EPR) lines, which make them an important class of probes and tags in biological applications and materials science. In this work, we propose a new approach to characterize librations by means of TAM radicals. The temperature dependence of motional parameter ⟨α2⟩τc, where ⟨α2⟩ is the mean-squared amplitude of librations and τc is their characteristic time, is obtained by comparison of the 1/ Tm phase-relaxation rates at X- and Q-band EPR frequencies. We study three soft matrixes, viz., glassy trehalose and two ionic liquids, using TAMs with optimized relaxation properties OX063D and a dodeca- n-butyl homologue of Finland trityl (DBT). The motional parameters ⟨α2⟩τc obtained using TAMs are in excellent agreement with those obtained by means of nitroxide radicals. At the same time, the new TAM-based approach has (1) greater sensitivity due to the narrower EPR spectrum and (2) greater measuring accuracy and broader temperature range due to longer relaxation times. The developed approach may be fruitfully implemented to probe low-temperature molecular motions of TAM-labeled biopolymers, membrane systems, polymers, molecules in glassy media, and ionic liquids.
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Affiliation(s)
- Andrey A Kuzhelev
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS , Novosibirsk 630090 , Russia.,International Tomography Center SB RAS , Novosibirsk 630090 , Russia.,Novosibirsk State University , Novosibirsk 630090 , Russia
| | - Olesya A Krumkacheva
- International Tomography Center SB RAS , Novosibirsk 630090 , Russia.,Novosibirsk State University , Novosibirsk 630090 , Russia
| | - Mikhail Yu Ivanov
- International Tomography Center SB RAS , Novosibirsk 630090 , Russia.,Novosibirsk State University , Novosibirsk 630090 , Russia
| | | | - Nicolay Yu Adonin
- Boreskov Institute of Catalysis SB RAS , Novosibirsk 630090 , Russia
| | - Victor M Tormyshev
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS , Novosibirsk 630090 , Russia.,Novosibirsk State University , Novosibirsk 630090 , Russia
| | - Michael K Bowman
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS , Novosibirsk 630090 , Russia.,University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - Matvey V Fedin
- International Tomography Center SB RAS , Novosibirsk 630090 , Russia.,Novosibirsk State University , Novosibirsk 630090 , Russia
| | - Elena G Bagryanskaya
- N.N. Vorozhtsov Institute of Organic Chemistry SB RAS , Novosibirsk 630090 , Russia.,Novosibirsk State University , Novosibirsk 630090 , Russia
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16
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Golysheva EA, Shevelev GY, Dzuba SA. Dynamical transition in molecular glasses and proteins observed by spin relaxation of nitroxide spin probes and labels. J Chem Phys 2018; 147:064501. [PMID: 28810753 DOI: 10.1063/1.4997035] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In glassy substances and biological media, dynamical transitions are observed in neutron scattering that manifests itself as deviations of the translational mean-squared displacement, 〈x2〉, of hydrogen atoms from harmonic dynamics. In biological media, the deviation occurs at two temperature intervals, at ∼100-150 K and at ∼170-230 K, and it is attributed to the motion of methyl groups in the former case and to the transition from harmonic to anharmonic or diffusive motions in the latter case. In this work, electron spin echo (ESE) spectroscopy-a pulsed version of electron paramagnetic resonance-is applied to study the spin relaxation of nitroxide spin probes and labels introduced in molecular glass former o-terphenyl and in protein lysozyme. The anisotropic contribution to the rate of the two-pulse ESE decay, ΔW, is induced by spin relaxation appearing because of restricted orientational stochastic molecular motion; it is proportional to 〈α2〉τc, where 〈α2〉 is the mean-squared angle of reorientation of the nitroxide molecule around the equilibrium position and τc is the correlation time of reorientation. The ESE time window allows us to study motions with τc < 10-7 s. For glassy o-terphenyl, the 〈α2〉τc temperature dependence shows a transition near 240 K, which is in agreement with the literature data on 〈x2〉. For spin probes of essentially different size, the obtained data were found to be close, which evidences that motion is cooperative, involving a nanocluster of several neighboring molecules. For the dry lysozyme, the 〈α2〉τc values below 260 K were found to linearly depend on the temperature in the same way as it was observed in neutron scattering for 〈x2〉. As spin relaxation is influenced only by stochastic motion, the harmonic motions seen in ESE must be overdamped. In the hydrated lysozyme, ESE data show transitions near 130 K for all nitroxides, near 160 K for the probe located in the hydration layer, and near 180 K for the label in the protein interior. For this system, the two latter transitions are not observed in neutron scattering. The ESE-detected transitions are suggested to be related with water dynamics in the nearest hydration shell: with water glass transition near 130 K and with the onset of overall water molecular reorientations near 180 K; the disagreement with neutron scattering is ascribed to the larger time window for ESE-detected motions.
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Affiliation(s)
- Elena A Golysheva
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
| | - Georgiy Yu Shevelev
- Department of Physics, Novosibirsk State University, Novosibirsk 630090, Russian Federation
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
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17
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Aloi E, Oranges M, Guzzi R, Bartucci R. Low-Temperature Dynamics of Chain-Labeled Lipids in Ester- and Ether-Linked Phosphatidylcholine Membranes. J Phys Chem B 2017; 121:9239-9246. [PMID: 28892381 DOI: 10.1021/acs.jpcb.7b07386] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Continuous wave electron paramagnetic resonance spectroscopy and two-pulse echo detected spectra of chain-labeled lipids are used to study the dynamics of frozen lipid membranes over the temperature range 77-260 K. Bilayers of ester-linked dihexadecanoylphosphatidylcholine (DPPC) with noninterdigitated chains and ether-linked dihexadecyl phosphatidylcholine (DHPC) with interdigitated chains are considered. Rapid stochastic librations of small angular amplitude are found in both lipid matrices. In noninterdigitated DPPC bilayers, the mean-square angular amplitude, [Formula: see text], of the motion increases with temperature and it is larger close to the chain termini than close to the polar/apolar interface. In contrast, in interdigitated DHPC lamellae, [Formula: see text] is small and temperature and label-position independent at low temperature and increases steeply at high temperature. The rotational correlation time, τc, of librations lies in the subnanosecond range for DPPC and in the nanosecond range for DHPC. In all membrane samples, the temperature dependence of [Formula: see text] resembles that of the mean-square atomic displacement revealed by neutron scattering and a dynamical transition is detected in the range 210-240 K. The results highlight the librational oscillations and the glass-like behavior in bilayer and interdigitated lipid membranes.
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Affiliation(s)
- Erika Aloi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
| | - Maria Oranges
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
| | - Rita Guzzi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
| | - Rosa Bartucci
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
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18
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Ivanov MY, Krumkacheva OA, Dzuba SA, Fedin MV. Microscopic rigidity and heterogeneity of ionic liquids probed by stochastic molecular librations of the dissolved nitroxides. Phys Chem Chem Phys 2017; 19:26158-26163. [DOI: 10.1039/c7cp04890d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We propose a new potent approach for studying nano/microscopic heterogeneities in ionic liquids exploiting stochastic librations of nitroxides and pulse EPR.
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Affiliation(s)
- Mikhail Yu. Ivanov
- International Tomography Center SB RAS
- Novosibirsk
- Russia
- Novosibirsk State University
- Novosibirsk
| | - Olesya A. Krumkacheva
- International Tomography Center SB RAS
- Novosibirsk
- Russia
- Novosibirsk State University
- Novosibirsk
| | - Sergei A. Dzuba
- Novosibirsk State University
- Novosibirsk
- Russia
- Voevodsky Institute of Chemical Kinetics and Combustion SB RAS
- Novosibirsk
| | - Matvey V. Fedin
- International Tomography Center SB RAS
- Novosibirsk
- Russia
- Novosibirsk State University
- Novosibirsk
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