1
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Simenido GA, Zubanova EM, Ksendzov EA, Kostjuk SV, Timashev PS, Golubeva EN. Bovine Serum Albumin Effect on Collapsing PNIPAM Chains in Aqueous Solutions: Spin Label and Spin Probe Study. Polymers (Basel) 2024; 16:1335. [PMID: 38794528 PMCID: PMC11124808 DOI: 10.3390/polym16101335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024] Open
Abstract
The influence of bovine serum albumin (BSA) on collapsing poly(N-isopropylacrylamide) (PNIPAM) chains was studied with turbidimetry and spin probe and spin label electron paramagnetic resonance spectroscopy. An increased ratio of collapsed chains in aqueous solutions in the narrow temperature region near the LCST appeared in the presence of 2.5-10 wt% BSA. The spin probe EPR data indicate that the inner cavities of the BSA dimers are probably responsive to the capture of small hydrophobic or amphiphilic molecules, such as TEMPO nitroxyl radical. The observed features of the structure and dynamics of inhomogeneities of aqueous PNIPAM-BSA solutions, including their mutual influence on the behavior of the polymer and protein below the LCST, should be considered when developing and investigating PNIPAM-based drug delivery systems.
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Affiliation(s)
- Georgii A. Simenido
- Faculty of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.M.Z.); (P.S.T.); (E.N.G.)
| | - Ekaterina M. Zubanova
- Faculty of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.M.Z.); (P.S.T.); (E.N.G.)
| | - Evgenii A. Ksendzov
- Research Institute for Physical Chemical Problems of the Belarusian State University, 220006 Minsk, Belarus; (E.A.K.); (S.V.K.)
- Faculty of Chemistry, Belarusian State University, 220006 Minsk, Belarus
| | - Sergei V. Kostjuk
- Research Institute for Physical Chemical Problems of the Belarusian State University, 220006 Minsk, Belarus; (E.A.K.); (S.V.K.)
- Faculty of Chemistry, Belarusian State University, 220006 Minsk, Belarus
- Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Peter S. Timashev
- Faculty of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.M.Z.); (P.S.T.); (E.N.G.)
- Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Elena N. Golubeva
- Faculty of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.M.Z.); (P.S.T.); (E.N.G.)
- Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
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2
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Podgorbunskikh E, Kuskov T, Matveeva A, Ulihin A, Bychkov A, Lomovskiy I, Polienko Y. Disordering of Starch Films as a Factor Influencing the Release Rate of Biologically Active Substances. Polymers (Basel) 2023; 15:polym15102303. [PMID: 37242877 DOI: 10.3390/polym15102303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
The release of a spin probe (nitroxide radical) from polymer films was studied by electron paramagnetic resonance (EPR). The films were fabricated from starch having different crystal structures (A-, B-, and C-types) and disordering degrees. Film morphology (analysis of the scanning electron microscopy (SEM)) depended on the presence of dopant (nitroxide radical) to a larger extent rather than on crystal structure ordering or polymorphic modification. The presence of nitroxide radical led to additional crystal structure disordering and reduced the crystallinity index from the X-ray diffraction (XRD) data. Polymeric films made of amorphized starch powder were able to undergo recrystallization (crystal structure rearrangement), which manifested itself as an increase in crystallinity index and phase transition of the A- and C-type crystal structures to the B-type one. It was demonstrated that nitroxide radical does not form an individual phase during film preparation. According to the EPR data, local permittivity of starch-based films varied from 52.5 to 60.1 F/m, while bulk permittivity did not exceed 17 F/m, which demonstrates that local concentration of water is increased in the regions near the nitroxide radical. The mobility of the spin probe corresponds to small stochastic librations and is indicative of the strongly a mobilized state. The application of kinetic models made it possible to find out that substance release from biodegradable films consists of two stages: matrix swelling and spin probe diffusion through the matrix. Investigation of the release kinetics for nitroxide radical demonstrated that the course of this process depends on the type of crystal structure of native starch.
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Affiliation(s)
- Ekaterina Podgorbunskikh
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze Str., 630090 Novosibirsk, Russia
| | - Timofei Kuskov
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze Str., 630090 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Str., 630090 Novosibirsk, Russia
| | - Anna Matveeva
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze Str., 630090 Novosibirsk, Russia
| | - Artem Ulihin
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze Str., 630090 Novosibirsk, Russia
| | - Aleksey Bychkov
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze Str., 630090 Novosibirsk, Russia
- Department of Business, Novosibirsk State Technical University, 20 Prospekt K. Marksa, 630073 Novosibirsk, Russia
| | - Igor Lomovskiy
- Institute of Solid State Chemistry and Mechanochemistry SB RAS, 18 Kutateladze Str., 630090 Novosibirsk, Russia
| | - Yuliya Polienko
- Laboratory of Nitrogen Compounds, N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Lavrentiev Ave., 630090 Novosibirsk, Russia
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3
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Structure and Dynamics of Inhomogeneities in Aqueous Solutions of Graft Copolymers of N-Isopropylacrylamide with Lactide (P(NIPAM-graft-PLA)) by Spin Probe EPR Spectroscopy. Polymers (Basel) 2022; 14:polym14214746. [DOI: 10.3390/polym14214746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Coil-to-globule transition and dynamics of inhomogeneities in aqueous solutions of graft copolymers of NIPAM with different content of oligolactide groups were studied using spin probe continuous wave EPR spectroscopy. The technique of the suppressing of TEMPO as spin probe by spin exchange with Cu2+ ions was applied. This approach allowed us to detect individual EPR spectra of the probe in collapsed globules and estimate its magnetic and dynamic parameters reliably. The formation of inhomogeneities at temperatures lower than the volume phase transition temperature measured via transmission, and differential scanning calorimetry was fixed. An increase in oligolactide content in copolymers leads to the formation of looser globules, allowing for the exchange of the probe molecules between the globules and the external solution.
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4
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Matei I, Ariciu AM, Popescu EI, Mocanu S, Neculae AVF, Savonea F, Ionita G. Evaluation of the Accessibility of Molecules in Hydrogels Using a Scale of Spin Probes. Gels 2022; 8:gels8070428. [PMID: 35877513 PMCID: PMC9316983 DOI: 10.3390/gels8070428] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/04/2022] [Accepted: 07/07/2022] [Indexed: 12/04/2022] Open
Abstract
In this work, we explored by means of electron paramagnetic resonance (EPR) spectroscopy the accessibility of a series of spin probes, covering a scale of molecular weights in the range of 200–60,000 Da, in a variety of hydrogels: covalent network, ionotropic, interpenetrating polymer network (IPN) and semi-IPN. The covalent gel network consists of polyethylene or polypropylene chains linked via isocyanate groups with cyclodextrin, and the ionotropic gel is generated by alginate in the presence of Ca2+ ions, whereas semi-IPN and IPN gel networks are generated in a solution of alginate and chitosan by adding crosslinking agents, Ca2+ for alginate and glutaraldehyde for chitosan. It was observed that the size of the diffusing species determines the ability of the gel to uptake them. Low molecular weight compounds can diffuse into the gel, but when the size of the probes increases, the gel cannot uptake them. Spin-labelled Pluronic F127 cannot be encapsulated by any covalent gel, whereas spin-labelled albumin can diffuse in alginate gels and in most of the IPN networks. The EPR spectra also evidenced the specific interactions of spin probes inside hydrogels. The results suggest that EPR spectroscopy can be an alternate method to evaluate the mesh size of gel systems and to provide information on local interactions inside gels.
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Affiliation(s)
- Iulia Matei
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Ana-Maria Ariciu
- IPG Health Consulting, King Edward Street, Macclesfield SK19 1AQ, UK;
| | - Elena Irina Popescu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Sorin Mocanu
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Alexandru Vincentiu Florian Neculae
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Florenta Savonea
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
| | - Gabriela Ionita
- “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania; (I.M.); (E.I.P.); (S.M.); (A.V.F.N.); (F.S.)
- Correspondence: or
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5
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Ionita G, Mocanu S, Matei I. Conformational preferences of TEMPO type radicals in complexes with cyclodextrins revealed by a combination of EPR spectroscopy, induced circular dichroism and molecular modeling. Phys Chem Chem Phys 2020; 22:12154-12165. [PMID: 32440670 DOI: 10.1039/d0cp01937b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy is the main tool for evidencing the formation of inclusion complexes of cyclodextrins with paramagnetic guests, based on changes in the EPR parameters. In-depth information on complexation can only be obtained by a combination of physico-chemical methods. Herein we report on the interaction of three TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) type radicals with cyclodextrins by collecting and analysing data provided experimentally by EPR and circular dichroism spectroscopies and theoretically by density functional theory and molecular docking. The study focused on the pH influence on the complexation of three paramagnetic probes with cyclodextrins. The EPR spectra revealed that the type and protonation state of the substituent linked to the TEMPO structure influences the affinity of the paramagnetic group for the cyclodextrin cavity. Neutral radical species favour stronger association with cyclodextrins and inclusion of the nitroxide group into the cavity, especially in the case of 4-carboxy-TEMPO. Induced circular dichroism signals of neutral species varied in sign and intensity as a function of substituent and cyclodextrin type. Density functional theory and molecular docking results supported the experimental data regarding the conformational preferences of TEMPO radicals in complexes with cyclodextrins.
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Affiliation(s)
- Gabriela Ionita
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
| | - Sorin Mocanu
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
| | - Iulia Matei
- "Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, Bucharest 060021, Romania.
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6
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Bogdanov AV, Bobrovsky AY, Vorobiev AK. The orientation order of liquid‐crystalline polymer, measured by ESR and optical dichroism techniques. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/polb.24836] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Alexey V. Bogdanov
- Chemistry DepartmentLomonosov Moscow State University Leninskie gory 1/3, Moscow 119991 Russian Federation
| | - Alexey Yu. Bobrovsky
- Chemistry DepartmentLomonosov Moscow State University Leninskie gory 1/3, Moscow 119991 Russian Federation
| | - Andrey Kh. Vorobiev
- Chemistry DepartmentLomonosov Moscow State University Leninskie gory 1/3, Moscow 119991 Russian Federation
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7
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Baratoiu R, Mocanu S, Matei I, Bem M, Hristea E, Tecuceanu V, Ionita G. A Comparison of the Behavior of Monomolecular and Dual Molecular Probes in F127/Cyclodextrin Systems. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201800489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Rodica Baratoiu
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Sorin Mocanu
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Iulia Matei
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Marioara Bem
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Elena Hristea
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
| | - Victorita Tecuceanu
- Romanian Academy; “Costin D. Nenitescu” Centre of Organic Chemistry; 202B Splaiul Independentei Bucharest 78100 Romania
| | - Gabriela Ionita
- Romanian Academy; “Ilie Murgulescu” Institute of Physical Chemistry; 202 Splaiul Independentei Bucharest 060021 Romania
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8
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Goswami S, Ray D, Otake KI, Kung CW, Garibay SJ, Islamoglu T, Atilgan A, Cui Y, Cramer CJ, Farha OK, Hupp JT. A porous, electrically conductive hexa-zirconium(iv) metal-organic framework. Chem Sci 2018; 9:4477-4482. [PMID: 29896389 PMCID: PMC5956983 DOI: 10.1039/c8sc00961a] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/11/2018] [Indexed: 12/23/2022] Open
Abstract
Engendering electrical conductivity in high-porosity metal-organic frameworks (MOFs) promises to unlock the full potential of MOFs for electrical energy storage, electrocatalysis, or integration of MOFs with conventional electronic materials. Here we report that a porous zirconium-node-containing MOF, NU-901, can be rendered electronically conductive by physically encapsulating C60, an excellent electron acceptor, within a fraction (ca. 60%) of the diamond-shaped cavities of the MOF. The cavities are defined by node-connected tetra-phenyl-carboxylated pyrene linkers, i.e. species that are excellent electron donors. The bulk electrical conductivity of the MOF is shown to increase from immeasurably low to 10-3 S cm-1, following fullerene incorporation. The observed conductivity originates from electron donor-acceptor interactions, i.e. charge-transfer interactions - a conclusion that is supported by density functional theory calculations and by the observation of a charge-transfer-derived band in the electronic absorption spectrum of the hybrid material. Notably, the conductive version of the MOF retains substantial nanoscale porosity and continues to display a sizable internal surface area, suggesting potential future applications that capitalize on the ability of the material to sorb molecular species.
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Affiliation(s)
- Subhadip Goswami
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
| | - Debmalya Ray
- Department of Chemistry , Chemical Theory Center , Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , MN 55455 , USA
| | - Ken-Ichi Otake
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
| | - Chung-Wei Kung
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
| | - Sergio J Garibay
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
| | - Timur Islamoglu
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
| | - Ahmet Atilgan
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
| | - Yuexing Cui
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
| | - Christopher J Cramer
- Department of Chemistry , Chemical Theory Center , Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , MN 55455 , USA
| | - Omar K Farha
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
- Department of Chemistry , King Abdulaziz University , Jeddah 21589 , Saudi Arabia
| | - Joseph T Hupp
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208 , USA .
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9
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Lappan U, Scheler U. Influence of the Nature of the Ion Pairs on the Segmental Dynamics in Polyelectrolyte Complex Coacervate Phases. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01858] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Uwe Lappan
- Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Ulrich Scheler
- Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
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10
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Lappan U, Wiesner B, Scheler U. Segmental Dynamics of Poly(acrylic acid) in Polyelectrolyte Complex Coacervates Studied by Spin-Label EPR Spectroscopy. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01863] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Uwe Lappan
- Leibniz-Institut für Polymerforschung
Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Brigitte Wiesner
- Leibniz-Institut für Polymerforschung
Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Ulrich Scheler
- Leibniz-Institut für Polymerforschung
Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
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11
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Zhang C, Peng H, Li W, Liu L, Puttick S, Reid J, Bernardi S, Searles DJ, Zhang A, Whittaker AK. Conformation Transitions of Thermoresponsive Dendronized Polymers across the Lower Critical Solution Temperature. Macromolecules 2016. [DOI: 10.1021/acs.macromol.5b02414] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cheng Zhang
- ARC
Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Hui Peng
- ARC
Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Wen Li
- Department
of Polymer Materials, Shanghai University, Shangda Street 99, Mailbox 152, Shanghai 200444, China
| | - Lianxiao Liu
- Department
of Polymer Materials, Shanghai University, Shangda Street 99, Mailbox 152, Shanghai 200444, China
| | - Simon Puttick
- ARC
Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, Brisbane, Qld 4072, Australia
| | | | | | | | - Afang Zhang
- Department
of Polymer Materials, Shanghai University, Shangda Street 99, Mailbox 152, Shanghai 200444, China
| | - Andrew K. Whittaker
- ARC
Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Queensland, Brisbane, Qld 4072, Australia
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12
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Hansen MR, Graf R, Spiess HW. Interplay of Structure and Dynamics in Functional Macromolecular and Supramolecular Systems As Revealed by Magnetic Resonance Spectroscopy. Chem Rev 2015; 116:1272-308. [DOI: 10.1021/acs.chemrev.5b00258] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Michael Ryan Hansen
- Max Planck Institute for Polymer Research, P.O. Box 3148, 55021 Mainz, Germany
| | - Robert Graf
- Max Planck Institute for Polymer Research, P.O. Box 3148, 55021 Mainz, Germany
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13
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Lappan U, Wiesner B, Scheler U. Rotational Dynamics of Spin-Labeled Polyacid Chain Segments in Polyelectrolyte Complexes Studied by CW EPR Spectroscopy. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00474] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Uwe Lappan
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Brigitte Wiesner
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Ulrich Scheler
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
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14
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Sun L, Hendon C, Minier MA, Walsh A, Dincă M. Million-Fold Electrical Conductivity Enhancement in Fe2(DEBDC) versus Mn2(DEBDC) (E = S, O). J Am Chem Soc 2015; 137:6164-7. [PMID: 25932955 PMCID: PMC4442594 DOI: 10.1021/jacs.5b02897] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Indexed: 12/21/2022]
Abstract
Reaction of FeCl2 and H4DSBDC (2,5-disulfhydrylbenzene-1,4-dicarboxylic acid) leads to the formation of Fe2(DSBDC), an analogue of M2(DOBDC) (MOF-74, DOBDC(4-) = 2,5-dihydroxybenzene-1,4-dicarboxylate). The bulk electrical conductivity values of both Fe2(DSBDC) and Fe2(DOBDC) are ∼6 orders of magnitude higher than those of the Mn(2+) analogues, Mn2(DEBDC) (E = O, S). Because the metals are of the same formal oxidation state, the increase in conductivity is attributed to the loosely bound Fe(2+) β-spin electron. These results provide important insight for the rational design of conductive metal-organic frameworks, highlighting in particular the advantages of iron for synthesizing such materials.
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Affiliation(s)
- Lei Sun
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
| | - Christopher
H. Hendon
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Mikael A. Minier
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
| | - Aron Walsh
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Mircea Dincă
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
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15
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Tatlidil D, Ucuncu M, Akdogan Y. Physiological concentrations of albumin favor drug binding. Phys Chem Chem Phys 2015; 17:22678-85. [DOI: 10.1039/c5cp03583j] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We exploit the direct measurements of spin labeled drugs to study drug binding to/release from protein using EPR spectroscopy.
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Affiliation(s)
- D. Tatlidil
- Materials Science and Engineering Department
- Ízmir Institute of Technology
- Ízmir
- Turkey
| | - M. Ucuncu
- Department of Chemistry
- Ízmir Institute of Technology
- Ízmir
- Turkey
| | - Y. Akdogan
- Materials Science and Engineering Department
- Ízmir Institute of Technology
- Ízmir
- Turkey
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16
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Caragheorgheopol A, Edwards W, Hardy JG, Smith DK, Chechik V. Using EPR spectroscopy as a unique probe of molecular-scale reorganization and solvation in self-assembled gel-phase materials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9210-9218. [PMID: 25017326 DOI: 10.1021/la501641q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We describe the synthesis of spin-labeled bis-ureas which coassemble with bis-urea gelators and report on self-assembly as detected using electron paramagnetic resonance spectroscopy (EPR). Specifically, EPR detects the gel-sol transition and allows us to quantify how much spin-label is immobilized within the gel fibers and how much is present in mobile solvent pools-as controlled by temperature, gelator structure, and thermal history. EPR is also able to report on the initial self-assembly processes below the gelation threshold which are not macroscopically visible and appears to be more sensitive than NMR to intermediate-sized nongelating oligomeric species. By studying dilute solutions of gelator molecules and using either single or double spin-labels, EPR allows quantification of the initial steps of the hierarchical self-assembly process in terms of cooperativity and association constant. Finally, EPR enables us to estimate the degree of gel-fiber solvation by probing the distances between spin-labels. Comparison of experimental data against the predicted distances assuming the nanofibers are only composed of gelator molecules indicates a significant difference, which can be assigned to the presence of a quantifiable number of explicit solvent molecules. In summary, EPR provides unique data and yields powerful insight into how molecular-scale mobility and solvation impact on assembly of supramolecular gels.
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Affiliation(s)
- Agneta Caragheorgheopol
- Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy , 202 Spl. Independentei, Bucharest 060021, Romania
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Telitel S, Amamoto Y, Poly J, Morlet-Savary F, Soppera O, Lalevée J, Matyjaszewski K. Introduction of self-healing properties into covalent polymer networks via the photodissociation of alkoxyamine junctions. Polym Chem 2014. [DOI: 10.1039/c3py01162c] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Hansen MR, Graf R, Spiess HW. Solid-state NMR in macromolecular systems: insights on how molecular entities move. Acc Chem Res 2013; 46:1996-2007. [PMID: 23480021 DOI: 10.1021/ar300338b] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The function of synthetic and natural macromolecularsystems critically depends on the packing and dynamics of the individual components of a given system. Not only can solid-state NMR provide structural information with atomic resolution, but it can also provide a way to characterize the amplitude and time scales of motions over broad ranges of length and time. These movements include molecular dynamics, rotational and translational motions of the building blocks, and also the motion of the functional species themselves, such as protons or ions. This Account examines solid-state NMR methods for correlating dynamics and function in a variety of chemical systems. In the early days, scientists thought that the rotationalmotions reflected the geometry of the moving entities. They described these phenomena as jumps about well-defined axes, such as phenyl flips, even in amorphous polymers. Later, they realized that conformational transitions in macromolecules happen in a much more complex way. Because the individual entities do not rotate around well-defined axes, they require much less space. Only recently researchers have appreciated the relative importance of large angle fluctuations of polymers over rotational jumps. Researchers have long considered that cooperative motions might be at work, yet only recently they have clearly detected these motions by NMR in macromolecular and supramolecular systems. In correlations of dynamics and function, local motions do not always provide the mechanism of long-range transport. This idea holds true in ion conduction but also applies to chain transport in polymer melts and semicrystalline polymers. Similar chain motions and ion transport likewise occur in functional biopolymers, systems where solid-state NMR studies are also performed. In polymer science, researchers have appreciated the unique information on molecular dynamics available from advanced solid-state NMR at times, where their colleagues in the biomacromolecular sciences have emphasized structure. By contrast, following X-ray crystallographers, researchers studying proteins using solution NMR introduced the combination of NMR with computer simulation before that became common practice in solid-state NMR. Today's simulation methods can handle partially ordered or even disordered systems common in synthetic polymers. Thus, the multitechnique approaches employed in NMR of synthetic and biological macromolecules have converged. Therefore, this Account will be relevant to both researchers studying synthetic macromolecular and supramolecular systems and those studying biological complexes.
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Affiliation(s)
- Michael Ryan Hansen
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Robert Graf
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Hans Wolfgang Spiess
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
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Spiess HW. Probing Macromolecular and Supramolecular Structure, Dynamics, and Function by Magnetic Resonance. HIERARCHICAL MACROMOLECULAR STRUCTURES: 60 YEARS AFTER THE STAUDINGER NOBEL PRIZE I 2013. [DOI: 10.1007/12_2013_255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Bercu V, Martinelli M, Pardi L, Massa CA, Leporini D. Dynamical Line-Shifts in High-Field Electron Spin Resonance: Applications to Polymer Physics. Z PHYS CHEM 2012. [DOI: 10.1524/zpch.2012.0283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abstract
High-field high-frequency Electron Paramagnetic Resonance spectroscopy (HF
2
-EPR) is a powerful tool to investigate, with ultra-high angular resolution, the rotational dynamics of complex systems like polymers, viscous fluids and glasses. Usually, information is drawn by detailed numerical analysis of the overall lineshape. Here, we present a simplified analytical model of the line shifts due to the rotational dynamics of the paramagnetic centre. The model captures the basic features of the reorientation process (time scale and size of the angular jump). It is compared with experimental results concerning the reorientation of a paramagnetic guest molecule dissolved in polystyrene. We find that, if the rotational model to describe the reorientation of the radical is consistent, the best-fit parameters yield equally acceptable best-fits of the overall spectrum by numerical simulations and dynamical line shifts by independent analytic expressions.
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Affiliation(s)
- Vasile Bercu
- University of Bucharest, Faculty of Physics, Bucharest, Rumänien
| | | | - Luca Pardi
- Istituto per i processi Chimico-Fisici (IPCF-CNR), Pisa, Italien
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Kurzbach D, Schömer M, Wilms VS, Frey H, Hinderberger D. How Structure-Related Collapse Mechanisms Determine Nanoscale Inhomogeneities in Thermoresponsive Polymers. Macromolecules 2012. [DOI: 10.1021/ma3014299] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Dennis Kurzbach
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz,
Germany
| | - Martina Schömer
- Department of Organic
Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14,
55128 Mainz, Germany
| | - Valerie S. Wilms
- Department of Organic
Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14,
55128 Mainz, Germany
- Graduate School “Materials Science in Mainz”, Staudingerweg 9, 55099 Mainz,
Germany
| | - Holger Frey
- Department of Organic
Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14,
55128 Mainz, Germany
| | - Dariush Hinderberger
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz,
Germany
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