1
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Levin I, Radulescu A, Liberman L, Cohen Y. Block Copolymer Adsorption on the Surface of Multi-Walled Carbon Nanotubes for Dispersion in N, N Dimethyl Formamide. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:838. [PMID: 36903716 PMCID: PMC10004759 DOI: 10.3390/nano13050838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/19/2023] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
This research aims to characterize the adsorption morphology of block copolymer dispersants of the styrene-block-4-vinylpyridine family (S4VP) on the surface of multi-walled carbon nanotubes (MWCNT) in a polar organic solvent, N,N-dimethyl formamide (DMF). Good, unagglomerated dispersion is important in several applications such as fabricating CNT nanocomposites in a polymer film for electronic or optical devices. Small-angle neutron scattering (SANS) measurements, using the contrast variation (CV) method, are used to evaluate the density and extension of the polymer chains adsorbed on the nanotube surface, which can yield insight into the means of successful dispersion. The results show that the block copolymers adsorb onto the MWCNT surface as a continuous coverage of low polymer concentration. Poly(styrene) (PS) blocks adsorb more tightly, forming a 20 Å layer containing about 6 wt.% PS, whereas poly(4-vinylpyridine) (P4VP) blocks emanate into the solvent, forming a thicker shell (totaling 110 Å in radius) but of very dilute (<1 wt.%) polymer concentration. This indicates strong chain extension. Increasing the PS molecular weight increases the thickness of the adsorbed layer but decreases the overall polymer concentration within it. These results are relevant for the ability of dispersed CNTs to form a strong interface with matrix polymers in composites, due to the extension of the 4VP chains allowing for entanglement with matrix chains. The sparse polymer coverage of the CNT surface may provide sufficient space to form CNT-CNT contacts in processed films and composites, which are important for electrical or thermal conductivity.
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Affiliation(s)
- Irena Levin
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Aurel Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-4) at Heinz Maier-Leibnitz Zentrum (MLZ), D-85747 Garching, Germany
| | - Lucy Liberman
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Yachin Cohen
- Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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2
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Spinozzi F, Alcaraz JP, Ortore MG, Gayet L, Radulescu A, Martin DK, Maccarini M. Small-Angle Neutron Scattering Reveals the Nanostructure of Liposomes with Embedded OprF Porins of Pseudomonas aeruginosa. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15026-15037. [PMID: 36459683 DOI: 10.1021/acs.langmuir.2c01342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The use of liposomes as drug delivery systems emerged in the last decades in view of their capacity and versatility to deliver a variety of therapeutic agents. By means of small-angle neutron scattering (SANS), we performed a detailed characterization of liposomes containing outer membrane protein F (OprF), the main porin of the Pseudomonas aeruginosa bacterium outer membrane. These OprF-liposomes are the basis of a novel vaccine against this antibiotic-resistant bacterium, which is one of the main hospital-acquired pathogens and causes each year a significant number of deaths. SANS data were analyzed by a specific model we created to quantify the crucial information about the structure of the liposome containing OprF, including the lipid bilayer structure, the amount of protein in the lipid bilayer, the average protein localization, and the effect of the protein incorporation on the lipid bilayer. Quantification of such structural information is important to enhance the design of liposomal delivery systems for therapeutic applications.
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Affiliation(s)
- Francesco Spinozzi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Jean-Pierre Alcaraz
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Maria Grazia Ortore
- Department of Life and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Landry Gayet
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Aurel Radulescu
- Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, 85748 Garching, Germany
| | - Donald K Martin
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Marco Maccarini
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
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3
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Zhao Y, Yoshimura K, Sawada S, Motegi T, Hiroki A, Radulescu A, Maekawa Y. Unique Structural Characteristics of Graft-Type Proton-Exchange Membranes Using SANS Partial Scattering Function Analysis. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yue Zhao
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gunma 370-1292, Japan
| | - Kimio Yoshimura
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gunma 370-1292, Japan
| | - Shinichi Sawada
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gunma 370-1292, Japan
| | - Toshinori Motegi
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gunma 370-1292, Japan
| | - Akihiro Hiroki
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gunma 370-1292, Japan
| | - Aurel Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science @ MLZ, Lichtenbergstraße 1, Garching D-85747, Germany
| | - Yasunari Maekawa
- Department of Advanced Functional Materials Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gunma 370-1292, Japan
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4
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Haris L, Biehl R, Dulle M, Radulescu A, Holderer O, Hoffmann I, Stadler AM. Variation of Structural and Dynamical Flexibility of Myelin Basic Protein in Response to Guanidinium Chloride. Int J Mol Sci 2022; 23:ijms23136969. [PMID: 35805997 PMCID: PMC9266411 DOI: 10.3390/ijms23136969] [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: 06/02/2022] [Revised: 06/18/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022] Open
Abstract
Myelin basic protein (MBP) is intrinsically disordered in solution and is considered as a conformationally flexible biomacromolecule. Here, we present a study on perturbation of MBP structure and dynamics by the denaturant guanidinium chloride (GndCl) using small-angle scattering and neutron spin–echo spectroscopy (NSE). A concentration of 0.2 M GndCl causes charge screening in MBP resulting in a compact, but still disordered protein conformation, while GndCl concentrations above 1 M lead to structural expansion and swelling of MBP. NSE data of MBP were analyzed using the Zimm model with internal friction (ZIF) and normal mode (NM) analysis. A significant contribution of internal friction was found in compact states of MBP that approaches a non-vanishing internal friction relaxation time of approximately 40 ns at high GndCl concentrations. NM analysis demonstrates that the relaxation rates of internal modes of MBP remain unaffected by GndCl, while structural expansion due to GndCl results in increased amplitudes of internal motions. Within the model of the Brownian oscillator our observations can be rationalized by a loss of friction within the protein due to structural expansion. Our study highlights the intimate coupling of structural and dynamical plasticity of MBP, and its fundamental difference to the behavior of ideal polymers in solution.
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Affiliation(s)
- Luman Haris
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Ralf Biehl
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
| | - Martin Dulle
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
| | - Aurel Radulescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungzentrum Jülich GmbH, 85747 Garching, Germany; (A.R.); (O.H.)
| | - Olaf Holderer
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungzentrum Jülich GmbH, 85747 Garching, Germany; (A.R.); (O.H.)
| | - Ingo Hoffmann
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, CEDEX 9, 38042 Grenoble, France;
| | - Andreas M. Stadler
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; (L.H.); (R.B.); (M.D.)
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
- Correspondence:
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5
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Balacescu L, Brandl G, Radulescu A. Separation of the inelastic and elastic scattering in time-of-flight mode on the pinhole small-angle neutron scattering diffractometer K-WS-2. J Appl Crystallogr 2021; 54:1217-1224. [PMID: 34429724 PMCID: PMC8366428 DOI: 10.1107/s1600576721006610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/24/2021] [Indexed: 02/19/2023] Open
Abstract
To study and control the incoherent inelastic background in small-angle neutron scattering, which makes a significant contribution to the detected scattering from hydrocarbon systems, the KWS-2 small-angle neutron scattering diffractometer operated by the Jülich Centre for Neutron Science (JCNS) at Heinz-Maier Leibnitz Zentrum (MLZ), Garching, Germany, was equipped with a secondary single-disc chopper that is placed in front of the sample stage. This makes it possible to record in time-of-flight mode the scattered neutrons in the high-Q regime of the instrument (i.e. short incoming wavelengths and detection distances) and to discard the inelastic component from the measured data. Examples of measurements on different materials routinely used as standard samples, sample containers and solvents in the experiments at KWS-2 are presented. When only the elastic region of the spectrum is used in the data-reduction procedure, a decrease of up to two times in the incoherent background of the experimentally measured scattering cross section may be obtained. The proof of principle is demonstrated on a solution of bovine serum albumin in D2O.
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Affiliation(s)
- Livia Balacescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
- Physikalisches Institut (IA), Rheinisch-Westfälische Technische Hochschule (RWTH), Otto-Blumenthal Strasse, Aachen, 52074, Germany
| | - Georg Brandl
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
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6
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Luchini A, Cavasso D, Radulescu A, D'Errico G, Paduano L, Vitiello G. Structural Organization of Cardiolipin-Containing Vesicles as Models of the Bacterial Cytoplasmic Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8508-8516. [PMID: 34213914 DOI: 10.1021/acs.langmuir.1c00981] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The bacterial cytoplasmic membrane is the innermost bacterial membrane and is mainly composed of three different phospholipid species, i.e., phosphoethanolamine (PE), phosphoglycerol (PG), and cardiolipin (CL). In particular, PG and CL are responsible for the negative charge of the membrane and are often the targets of cationic antimicrobial agents. The growing resistance of bacteria toward the available antibiotics requires the development of new and more efficient antibacterial drugs. In this context, studying the physicochemical properties of the bacterial cytoplasmic membrane is pivotal for understanding drug-membrane interactions at the molecular level as well as for designing drug-testing platforms. Here, we discuss the preparation and characterization of PE/PG/CL vesicle suspensions, which contain all of the main lipid components of the bacterial cytoplasmic membrane. The vesicle suspensions were characterized by means of small-angle neutron scattering, dynamic light scattering, and electron paramagnetic spectroscopy. By combining solution scattering and spectroscopy techniques, we propose a detailed description of the impact of different CL concentrations on the structure and dynamics of the PE/PG bilayer. CL induces the formation of thicker bilayers, which exhibit higher curvature and are overall more fluid. The experimental results contribute to shed light on the structure and dynamics of relevant model systems of the bacterial cytoplasmic membrane.
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Affiliation(s)
- Alessandra Luchini
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Domenico Cavasso
- Department of Chemical Science, University of Naples Federico II, Complesso di Monte Sant'Angelo, Via Cinthia 4, 80126 Naples, Italy
| | - Aurel Radulescu
- Jülich Centre for Neutron Science, Garching Forschungszentrum, Lichtenbergstrasse 1, D-85747 Garching bei München, Germany
| | - Gerardino D'Errico
- Department of Chemical Science, University of Naples Federico II, Complesso di Monte Sant'Angelo, Via Cinthia 4, 80126 Naples, Italy
- CSGI, Center for Colloid and Surface Science, Via della Lastruccia 3, 50019 Sesto Fiorentino FI, Italy
| | - Luigi Paduano
- Department of Chemical Science, University of Naples Federico II, Complesso di Monte Sant'Angelo, Via Cinthia 4, 80126 Naples, Italy
- CSGI, Center for Colloid and Surface Science, Via della Lastruccia 3, 50019 Sesto Fiorentino FI, Italy
| | - Giuseppe Vitiello
- CSGI, Center for Colloid and Surface Science, Via della Lastruccia 3, 50019 Sesto Fiorentino FI, Italy
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
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7
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Hamada T, Yoshimura K, Takeuchi K, Watanabe S, Zhao Y, Hiroki A, Hagiwara T, Shishitani H, Yamaguchi S, Tanaka H, Radulescu A, Ohwada K, Maekawa Y. Synthesis and Characterization of 4‐Vinylimidazolium/Styrene‐Cografted Anion‐Conducting Electrolyte Membranes. MACROMOL CHEM PHYS 2021. [DOI: 10.1002/macp.202100028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Takashi Hamada
- Department of Advanced Functional Materials Research Takasaki Advanced Radiation Research Institute Quantum Beam Science Research Directorate National Institutes for Quantum and Radiological Science and Technology (QST) 1233 Watanuki, Takasaki Gunma 370‐1292 Japan
| | - Kimio Yoshimura
- Department of Advanced Functional Materials Research Takasaki Advanced Radiation Research Institute Quantum Beam Science Research Directorate National Institutes for Quantum and Radiological Science and Technology (QST) 1233 Watanuki, Takasaki Gunma 370‐1292 Japan
| | - Kota Takeuchi
- Graduate School of Science and Technology Gunma University 1‐5‐1 Tenjin‐cho, Kiryu Gunma 376‐8515 Japan
| | - Shun Watanabe
- Graduate School of Engineering Saitama Institute of Technology 1690 Fusaiji, Fukaya Saitama 369‐0293 Japan
| | - Yue Zhao
- Department of Advanced Functional Materials Research Takasaki Advanced Radiation Research Institute Quantum Beam Science Research Directorate National Institutes for Quantum and Radiological Science and Technology (QST) 1233 Watanuki, Takasaki Gunma 370‐1292 Japan
| | - Akihiro Hiroki
- Department of Advanced Functional Materials Research Takasaki Advanced Radiation Research Institute Quantum Beam Science Research Directorate National Institutes for Quantum and Radiological Science and Technology (QST) 1233 Watanuki, Takasaki Gunma 370‐1292 Japan
| | - Tokio Hagiwara
- Graduate School of Engineering Saitama Institute of Technology 1690 Fusaiji, Fukaya Saitama 369‐0293 Japan
| | - Hideyuki Shishitani
- Daihatsu Motor Co., Ltd. 3000 Ohaza Yamanoue, Ryuo Gamo Shiga 520‐2593 Japan
| | - Susumu Yamaguchi
- Daihatsu Motor Co., Ltd. 3000 Ohaza Yamanoue, Ryuo Gamo Shiga 520‐2593 Japan
| | - Hirohisa Tanaka
- Daihatsu Motor Co., Ltd. 3000 Ohaza Yamanoue, Ryuo Gamo Shiga 520‐2593 Japan
| | - Aurel Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science@MLZ Lichtenbergstraße 1 Garching D‐85747 Germany
| | - Kenji Ohwada
- Synchrotron Radiation Research Center Quantum Beam Science Research Directorate National Institutes for Quantum and Radiological Science and Technology (QST) 1‐1‐1 Kouto, Sayo Hyogo 679‐5148 Japan
| | - Yasunari Maekawa
- Department of Advanced Functional Materials Research Takasaki Advanced Radiation Research Institute Quantum Beam Science Research Directorate National Institutes for Quantum and Radiological Science and Technology (QST) 1233 Watanuki, Takasaki Gunma 370‐1292 Japan
- Graduate School of Science and Technology Gunma University 1‐5‐1 Tenjin‐cho, Kiryu Gunma 376‐8515 Japan
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8
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Light Scattering and Absorption Complementarities to Neutron Scattering: In Situ FTIR and DLS Techniques at the High-Intensity and Extended Q-Range SANS Diffractometer KWS-2. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11115135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding soft and biological materials requires global knowledge of their microstructural features from elementary units at the nm scale up to larger complex aggregates in the micrometer range. Such a wide range of scale can be explored using the KWS-2 small-angle neutron (SANS) diffractometer. Additional information obtained by in situ complementary techniques sometimes supports the SANS analysis of systems undergoing structural modifications under external stimuli or which are stable only for short times. Observations at the local molecular level structure and conformation assists with an unambiguous interpretation of the SANS data using appropriate structural models, while monitoring of the sample condition during the SANS investigation ensures the sample stability and desired composition and chemical conditions. Thus, we equipped the KWS-2 with complementary light absorption and scattering capabilities: Fourier transform infrared (FTIR) spectroscopy can now be performed simultaneously with standard and time-resolved SANS, while in situ dynamic light scattering (DLS) became available for routine experiments, which enables the observation of either changes in the sample composition, due to sedimentation effects, or in size of morphologies, due to aggregation processes. The performance of each setup is demonstrated here using systems representative of those typically investigated on this beamline and benchmarked to studies performed offline.
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9
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Sebastiani F, Yanez Arteta M, Lerche M, Porcar L, Lang C, Bragg RA, Elmore CS, Krishnamurthy VR, Russell RA, Darwish T, Pichler H, Waldie S, Moulin M, Haertlein M, Forsyth VT, Lindfors L, Cárdenas M. Apolipoprotein E Binding Drives Structural and Compositional Rearrangement of mRNA-Containing Lipid Nanoparticles. ACS NANO 2021; 15:6709-6722. [PMID: 33754708 PMCID: PMC8155318 DOI: 10.1021/acsnano.0c10064] [Citation(s) in RCA: 128] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/18/2021] [Indexed: 05/05/2023]
Abstract
Emerging therapeutic treatments based on the production of proteins by delivering mRNA have become increasingly important in recent times. While lipid nanoparticles (LNPs) are approved vehicles for small interfering RNA delivery, there are still challenges to use this formulation for mRNA delivery. LNPs are typically a mixture of a cationic lipid, distearoylphosphatidylcholine (DSPC), cholesterol, and a PEG-lipid. The structural characterization of mRNA-containing LNPs (mRNA-LNPs) is crucial for a full understanding of the way in which they function, but this information alone is not enough to predict their fate upon entering the bloodstream. The biodistribution and cellular uptake of LNPs are affected by their surface composition as well as by the extracellular proteins present at the site of LNP administration, e.g., apolipoproteinE (ApoE). ApoE, being responsible for fat transport in the body, plays a key role in the LNP's plasma circulation time. In this work, we use small-angle neutron scattering, together with selective lipid, cholesterol, and solvent deuteration, to elucidate the structure of the LNP and the distribution of the lipid components in the absence and the presence of ApoE. While DSPC and cholesterol are found to be enriched at the surface of the LNPs in buffer, binding of ApoE induces a redistribution of the lipids at the shell and the core, which also impacts the LNP internal structure, causing release of mRNA. The rearrangement of LNP components upon ApoE incubation is discussed in terms of potential relevance to LNP endosomal escape.
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Affiliation(s)
- Federica Sebastiani
- Biofilms
- Research Center for Biointerfaces and Department of Biomedical Science,
Faculty of Health and Society, Malmö
University, 20506 Malmö, Sweden
| | - Marianna Yanez Arteta
- Advanced
Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, 431 83 Gothenburg Sweden
| | - Michael Lerche
- Advanced
Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, 431 83 Gothenburg Sweden
| | - Lionel Porcar
- Large
Scale Structures, Institut Laue Langevin, Grenoble F-38042, France
| | - Christian Lang
- Forschungszentrum
Jülich GmbH, Jülich Centre for Neutron Science JCNS,
Outstation at Heinz Maier-Leibnitz Zentrum, Lichtenbergstraße 1, 85748 Garching, Germany
| | - Ryan A. Bragg
- Early
Chemical Development, Pharmaceutical Sciences, R&D, AstraZeneca, SK 10 4TG Cambridge, U.K.
| | - Charles S. Elmore
- Early Chemical
Development, Pharmaceutical Sciences, R&D, AstraZeneca, 431 83 Gothenburg, Sweden
| | - Venkata R. Krishnamurthy
- Advanced
Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, CB2 0AA Boston, Massachusetts 02451, United States
| | - Robert A. Russell
- National
Deuteration Facility (NDF), Australian Nuclear
Science and Technology Organisation (ANSTO), Lucas Heights, 2232 Sydney, NSW, Australia
| | - Tamim Darwish
- National
Deuteration Facility (NDF), Australian Nuclear
Science and Technology Organisation (ANSTO), Lucas Heights, 2232 Sydney, NSW, Australia
| | - Harald Pichler
- Austrian
Centre of Industrial Biotechnology, Petersgasse 14, 8010, Graz, Austria
- Institute
of Molecular Biotechnology, Graz University
of Technology, NAWI Graz,
BioTechMed Graz, Petersgasse 14, 8010, Graz, Austria
| | - Sarah Waldie
- Biofilms
- Research Center for Biointerfaces and Department of Biomedical Science,
Faculty of Health and Society, Malmö
University, 20506 Malmö, Sweden
- Life
Sciences Group, Institut Laue Langevin, Grenoble F-38042, France
- Partnership for Structural Biology (PSB), Grenoble F-38042, France
| | - Martine Moulin
- Life
Sciences Group, Institut Laue Langevin, Grenoble F-38042, France
- Partnership for Structural Biology (PSB), Grenoble F-38042, France
| | - Michael Haertlein
- Life
Sciences Group, Institut Laue Langevin, Grenoble F-38042, France
- Partnership for Structural Biology (PSB), Grenoble F-38042, France
| | - V. Trevor Forsyth
- Life
Sciences Group, Institut Laue Langevin, Grenoble F-38042, France
- Partnership for Structural Biology (PSB), Grenoble F-38042, France
- Faculty
of Natural Sciences, Keele University, Staffordshire, ST5 5BG, U.K.
| | - Lennart Lindfors
- Advanced
Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, 431 83 Gothenburg Sweden
| | - Marité Cárdenas
- Biofilms
- Research Center for Biointerfaces and Department of Biomedical Science,
Faculty of Health and Society, Malmö
University, 20506 Malmö, Sweden
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10
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Casillo A, Fabozzi A, Russo Krauss I, Parrilli E, Biggs CI, Gibson MI, Lanzetta R, Appavou MS, Radulescu A, Tutino ML, Paduano L, Corsaro MM. Physicochemical Approach to Understanding the Structure, Conformation, and Activity of Mannan Polysaccharides. Biomacromolecules 2021; 22:1445-1457. [PMID: 33729771 PMCID: PMC8045027 DOI: 10.1021/acs.biomac.0c01659] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
![]()
Extracellular
polysaccharides are widely produced by bacteria, yeasts, and algae.
These polymers are involved in several biological functions, such
as bacteria adhesion to surface and biofilm formation, ion sequestering,
protection from desiccation, and cryoprotection. The chemical characterization
of these polymers is the starting point for obtaining relationships
between their structures and their various functions. While this fundamental
correlation is well reported and studied for the proteins, for the
polysaccharides, this relationship is less intuitive. In this paper,
we elucidate the chemical structure and conformational studies of
a mannan exopolysaccharide from the permafrost isolated bacterium Psychrobacter arcticus strain 273-4. The mannan from
the cold-adapted bacterium was compared with its dephosphorylated
derivative and the commercial product from Saccharomyces
cerevisiae. Starting from the chemical structure,
we explored a new approach to deepen the study of the structure/activity
relationship. A pool of physicochemical techniques, ranging from small-angle
neutron scattering (SANS) and dynamic and static light scattering
(DLS and SLS, respectively) to circular dichroism (CD) and cryo-transmission
electron microscopy (cryo-TEM), have been used. Finally, the ice recrystallization
inhibition activity of the polysaccharides was explored. The experimental
evidence suggests that the mannan exopolysaccharide from P. arcticus bacterium has an efficient interaction
with the water molecules, and it is structurally characterized by
rigid-rod regions assuming a 14-helix-type conformation.
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Affiliation(s)
- Angela Casillo
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - Antonio Fabozzi
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - Irene Russo Krauss
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.,CSGI - Consorzio per lo Sviluppo dei Sistemi a Grande Interfase, Florence 50019, Italy
| | - Ermenegilda Parrilli
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - Caroline I Biggs
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Matthew I Gibson
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.,Warwick Medical School, University of Warwick, Coventry CV4 7AL, U.K
| | - Rosa Lanzetta
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - Marie-Sousai Appavou
- Jülich Centre for Neutron Science, Garching Forschungszentrum, Lichtenbergstrasse 1, D-857478 Garching bei München, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science, Garching Forschungszentrum, Lichtenbergstrasse 1, D-857478 Garching bei München, Germany
| | - Maria L Tutino
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - Luigi Paduano
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.,CSGI - Consorzio per lo Sviluppo dei Sistemi a Grande Interfase, Florence 50019, Italy
| | - Maria M Corsaro
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
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11
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Davies N, Hovdal D, Edmunds N, Nordberg P, Dahlén A, Dabkowska A, Arteta MY, Radulescu A, Kjellman T, Höijer A, Seeliger F, Holmedal E, Andihn E, Bergenhem N, Sandinge AS, Johansson C, Hultin L, Johansson M, Lindqvist J, Björsson L, Jing Y, Bartesaghi S, Lindfors L, Andersson S. Functionalized lipid nanoparticles for subcutaneous administration of mRNA to achieve systemic exposures of a therapeutic protein. MOLECULAR THERAPY-NUCLEIC ACIDS 2021; 24:369-384. [PMID: 33868782 PMCID: PMC8039535 DOI: 10.1016/j.omtn.2021.03.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 03/10/2021] [Indexed: 01/05/2023]
Abstract
Lipid nanoparticles (LNPs) are the most clinically advanced delivery system for RNA-based drugs but have predominantly been investigated for intravenous and intramuscular administration. Subcutaneous administration opens the possibility of patient self-administration and hence long-term chronic treatment that could enable messenger RNA (mRNA) to be used as a novel modality for protein replacement or regenerative therapies. In this study, we show that subcutaneous administration of mRNA formulated within LNPs can result in measurable plasma exposure of a secreted protein. However, subcutaneous administration of mRNA formulated within LNPs was observed to be associated with dose-limiting inflammatory responses. To overcome this limitation, we investigated the concept of incorporating aliphatic ester prodrugs of anti-inflammatory steroids within LNPs, i.e., functionalized LNPs to suppress the inflammatory response. We show that the effectiveness of this approach depends on the alkyl chain length of the ester prodrug, which determines its retention at the site of administration. An unexpected additional benefit to this approach is the prolongation observed in the duration of protein expression. Our results demonstrate that subcutaneous administration of mRNA formulated in functionalized LNPs is a viable approach to achieving systemic levels of therapeutic proteins, which has the added benefits of being amenable to self-administration when chronic treatment is required.
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Affiliation(s)
- Nigel Davies
- Pharmaceutical Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Daniel Hovdal
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Nicholas Edmunds
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge SG8 6HB, UK
| | - Peter Nordberg
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Anders Dahlén
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | | | | | - Aurel Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at Maier-Leibnitz Zentrum, 85748 Garching, Germany
| | - Tomas Kjellman
- Pharmaceutical Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Andreas Höijer
- Pharmaceutical Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Frank Seeliger
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Elin Holmedal
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Elisabeth Andihn
- Global Project and Portfolio Management, AstraZeneca, 43183 Gothenburg, Sweden
| | - Nils Bergenhem
- Alliance Management, BioPharmaceuticals R&D, AstraZeneca, Boston, MA 02451, USA
| | - Ann-Sofie Sandinge
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Camilla Johansson
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Leif Hultin
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Marie Johansson
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Johnny Lindqvist
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Liselotte Björsson
- Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Yujia Jing
- Pharmaceutical Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Stefano Bartesaghi
- Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Lennart Lindfors
- Pharmaceutical Sciences, R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Shalini Andersson
- Oligonucleotide Discovery, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
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12
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Fischer J, Radulescu A, Falus P, Richter D, Biehl R. Structure and Dynamics of Ribonuclease A during Thermal Unfolding: The Failure of the Zimm Model. J Phys Chem B 2021; 125:780-788. [PMID: 33470118 DOI: 10.1021/acs.jpcb.0c09476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Disordered regions as found in intrinsically disordered proteins (IDP) or during protein folding define response time to stimuli and protein folding times. Neutron spin-echo spectroscopy is a powerful tool to directly access the collective motions of the unfolded chain to enlighten the physical origin of basic conformational relaxation. During the thermal unfolding of native ribonuclease A, we examine the structure and dynamics of the disordered state within a two-state transition model using polymer models, including internal friction, to describe the chain dynamics. The presence of four disulfide bonds alters the disordered configuration to a more compact configuration compared to a Gaussian chain that is defined by the additional links, as demonstrated by coarse-grained simulation. The dynamics of the disordered chain is described by Zimm dynamics with internal friction (ZIF) between neighboring amino acids. Relaxation times are dominated by mode-independent internal friction. Internal friction relaxation times show an Arrhenius-like behavior with an activation energy of 33 kJ/mol. The Zimm dynamics is dominated by internal friction and suggest that the characteristic motions correspond to overdamped elastic modes similar to the motions observed for folded proteins but within a pool of disordered configurations spanning the configurational space. For IDP, internal friction dominates while solvent friction and hydrodynamic interactions are smaller corrections.
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Affiliation(s)
- Jennifer Fischer
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich, 85748 Garching, Germany
| | - Peter Falus
- Institut Laue-Langevin (ILL), 71 rue des Martyrs, 38042 Grenoble, Cedex 9, France
| | - Dieter Richter
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Ralf Biehl
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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13
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Advanced Small-Angle Scattering Instrument Available in the Tokyo Area. Time-Of-Flight, Small-Angle Neutron Scattering Developed on the iMATERIA Diffractometer at the High Intensity Pulsed Neutron Source J-PARC. QUANTUM BEAM SCIENCE 2020. [DOI: 10.3390/qubs4040042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A method of time-of-flight, small-angle neutron scattering (TOF-SANS) has been developed based on the iMATERIA powder diffractometer at BL20, of the Materials and Life Sciences Facility (MLF) at the high-intensity proton accelerator (J-PARC). A large-area detector for SANS, which is composed of triple-layered 3He tube detectors, has a hole at its center in order to release a direct beam behind and to detect ultra-small-angle scattering. As a result, the pulsed-neutron TOF method enables us to perform multiscale observations covering 0.003 < q (Å−1) < 40 (qmax/qmix = 1.3 × 104) and to determine the static structure factor S(q) and/or form factor P(q) under real-time and in-situ conditions. Our challenge, using unique sample accessories of a super-conducting magnet and polarized neutron, is dynamic nuclear polarization (DNP) for contrast variation, especially for industrial use. To reinforce conventional SANS measurements with powder materials, grazing-incidence small-angle neutron scattering (GISANS) or reflectivity is also available on the iMATERIA instrument.
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14
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Scotti A, Houston JE, Brugnoni M, Schmidt MM, Schulte MF, Bochenek S, Schweins R, Feoktystov A, Radulescu A, Richtering W. Phase behavior of ultrasoft spheres show stable bcc lattices. Phys Rev E 2020; 102:052602. [PMID: 33327194 DOI: 10.1103/physreve.102.052602] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/01/2020] [Indexed: 06/12/2023]
Abstract
The phase behavior of supersoft spheres is explored using solutions of ultralow cross-linked poly(N-isopropylacrylamide)-based microgels as a model system. For these microgels, the effects of the electric charges on their surfaces can be neglected and therefore only the role of softness on the phase behavior is investigated. The samples show a liquid-to-crystal transition at higher volume fraction with respect to both hard spheres and stiffer microgels. Furthermore, stable body centered cubic (bcc) crystals are observed in addition to the expected face centered cubic (fcc) crystals. Small-angle x-ray and neutron scattering with contrast variation allow the characterization of both the microgel-to-microgel distance and the architecture of single microgels in crowded solutions. The measurements reveal that the stable bcc crystals depend on the interplay between the collapse and the interpenetration of the external shell of the ultralow cross-linked microgels.
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Affiliation(s)
- A Scotti
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - J E Houston
- European Spallation Source ERIC, Box 176, SE-221 00 Lund, Sweden
| | - M Brugnoni
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - M M Schmidt
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - M F Schulte
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - S Bochenek
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - R Schweins
- Institut Laue-Langevin ILL DS/LSS, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - A Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ, 85748 Garching, Germany
| | - A Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ, 85748 Garching, Germany
| | - W Richtering
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
- JARA-SOFT, 52056 Aachen, Germany
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15
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Hybrid Biopolymer and Lipid Nanoparticles with Improved Transfection Efficacy for mRNA. Cells 2020; 9:cells9092034. [PMID: 32899484 PMCID: PMC7563888 DOI: 10.3390/cells9092034] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022] Open
Abstract
Hybrid nanoparticles from lipidic and polymeric components were assembled to serve as vehicles for the transfection of messenger RNA (mRNA) using different portions of the cationic lipid DOTAP (1,2-Dioleoyl-3-trimethylammonium-propane) and the cationic biopolymer protamine as model systems. Two different sequential assembly approaches in comparison with a direct single-step protocol were applied, and molecular organization in correlation with biological activity of the resulting nanoparticle systems was investigated. Differences in the structure of the nanoparticles were revealed by thorough physicochemical characterization including small angle neutron scattering (SANS), small angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). All hybrid systems, combining lipid and polymer, displayed significantly increased transfection in comparison to lipid/mRNA and polymer/mRNA particles alone. For the hybrid nanoparticles, characteristic differences regarding the internal organization, release characteristics, and activity were determined depending on the assembly route. The systems with the highest transfection efficacy were characterized by a heterogenous internal organization, accompanied by facilitated release. Such a system could be best obtained by the single step protocol, starting with a lipid and polymer mixture for nanoparticle formation.
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16
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Russo Krauss I, Picariello A, Vitiello G, De Santis A, Koutsioubas A, Houston JE, Fragneto G, Paduano L. Interaction with Human Serum Proteins Reveals Biocompatibility of Phosphocholine-Functionalized SPIONs and Formation of Albumin-Decorated Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8777-8791. [PMID: 32575987 PMCID: PMC8008447 DOI: 10.1021/acs.langmuir.0c01083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/23/2020] [Indexed: 05/13/2023]
Abstract
Nanoparticles (NPs) are increasingly exploited as diagnostic and therapeutic devices in medicine. Among them, superparamagnetic nanoparticles (SPIONs) represent very promising tools for magnetic resonance imaging, local heaters for hyperthermia, and nanoplatforms for multimodal imaging and theranostics. However, the use of NPs, including SPIONs, in medicine presents several issues: first, the encounter with the biological world and proteins in particular. Indeed, nanoparticles can suffer from protein adsorption, which can affect NP functionality and biocompatibility. In this respect, we have investigated the interaction of small SPIONs covered by an amphiphilic double layer of oleic acid/oleylamine and 1-octadecanoyl-sn-glycero-3-phosphocholine with two abundant human plasma proteins, human serum albumin (HSA) and human transferrin. By means of spectroscopic and scattering techniques, we analyzed the effect of SPIONs on protein structure and the binding affinities, and only found strong binding in the case of HSA. In no case did SPIONs alter the protein structure significantly. We structurally characterized HSA/SPIONs complexes by means of light and neutron scattering, highlighting the formation of a monolayer of protein molecules on the NP surface. Their interaction with lipid bilayers mimicking biological membranes was investigated by means of neutron reflectivity. We show that HSA/SPIONs do not affect lipid bilayer features and could be further exploited as a nanoplatform for future applications. Overall, our findings point toward a high biocompatibility of phosphocholine-decorated SPIONs and support their use in nanomedicine.
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Affiliation(s)
- Irene Russo Krauss
- Department
of Chemical Sciences and Department of Chemical, Materials
and Production Engineering, University of
Naples Federico II, Naples, Italy
- CSGI,
Center for Colloid and Surface Science, Sesto Fiorentino (FI), Italy
| | - Alessandra Picariello
- Department
of Chemical Sciences and Department of Chemical, Materials
and Production Engineering, University of
Naples Federico II, Naples, Italy
| | - Giuseppe Vitiello
- Department
of Chemical Sciences and Department of Chemical, Materials
and Production Engineering, University of
Naples Federico II, Naples, Italy
- CSGI,
Center for Colloid and Surface Science, Sesto Fiorentino (FI), Italy
| | - Augusta De Santis
- Department
of Chemical Sciences and Department of Chemical, Materials
and Production Engineering, University of
Naples Federico II, Naples, Italy
- CSGI,
Center for Colloid and Surface Science, Sesto Fiorentino (FI), Italy
| | - Alexandros Koutsioubas
- Jülich
Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum
(MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, 85747 Garching, Germany
| | | | - Giovanna Fragneto
- Institut
Laue-Langevin (ILL), 71 avenue des Martyrs, BP 156, 38042 Grenoble, France
| | - Luigi Paduano
- Department
of Chemical Sciences and Department of Chemical, Materials
and Production Engineering, University of
Naples Federico II, Naples, Italy
- CSGI,
Center for Colloid and Surface Science, Sesto Fiorentino (FI), Italy
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17
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Le Coeur C, Lorthioir C, Feoktystov A, Wu B, Volet G, Amiel C. Laponite/poly(2-methyl-2-oxazoline) hydrogels: Interplay between local structure and rheological behaviour. J Colloid Interface Sci 2020; 582:149-158. [PMID: 32814221 DOI: 10.1016/j.jcis.2020.07.068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/11/2020] [Accepted: 07/13/2020] [Indexed: 11/08/2022]
Abstract
HYPOTHESIS Dispersions of Laponite in water may form gels, the rheological properties of which being possibly tuned by the addition of polymer chains. Laponite-based hydrogels with poly(ethylene oxide) (PEO) were the most widely investigated systems and the PEO chains were then found to reduce the elastic modulus. EXPERIMENTS Here, hydrogels based on Laponite and poly(2-methyl-2-oxazoline) (POXA) were considered. The adsorption behavior and the local structures within these nanocomposite gels were investigated by small-angle neutron scattering and NMR. The same materials were macroscopically characterized using rheology. FINDINGS An original evolution of the storage modulus G' with the POXA concentration is evidenced compared to Laponite/PEO hydrogels. At low POXA concentrations, a continuous reduction of G' is observed upon increasing the polymer content, as with PEO, due to the screening of electrostatic interactions between the clay platelets. However, above a critical value of the POXA concentration, G' increases with the polymer content. This difference with PEO-based hydrogels is correlated to the stronger affinity of POXA chains for the clay surfaces, which results in the reduction of the inhomogeneities for the Laponite disks within the gels. Steric repulsions would then counterbalance the effect of electrostatic repulsions and lead to the strengthening of the POXA-based hydrogels.
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Affiliation(s)
- C Le Coeur
- Université Paris Est Creteil, CNRS, Institut Chimie et Matériaux Paris Est, 2 Rue Henri Dunant, 94320 Thiais, France; Laboratoire Léon Brillouin, CEA-CNRS (UMR-12), CEA Saclay, Université Paris-Saclay, 91191 Gif-sur-Yvette Cedex, France.
| | - C Lorthioir
- Sorbonne Université, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, 4 Place Jussieu, 75005 Paris, France.
| | - A Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ, Lichtenbergstraße 1, 85748 Garching, Germany.
| | - B Wu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ, Lichtenbergstraße 1, 85748 Garching, Germany.
| | - G Volet
- Université Paris Est Creteil, CNRS, Institut Chimie et Matériaux Paris Est, 2 Rue Henri Dunant, 94320 Thiais, France; Université d'Evry Val d'Essonne, Rue du Père Jarlan, 91025 Evry Cedex, France.
| | - C Amiel
- Université Paris Est Creteil, CNRS, Institut Chimie et Matériaux Paris Est, 2 Rue Henri Dunant, 94320 Thiais, France.
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18
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Pasini S, Maccarrone S, Székely NK, Stingaciu LR, Gelissen APH, Richtering W, Monkenbusch M, Holderer O. Fluctuation suppression in microgels by polymer electrolytes. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:034302. [PMID: 32566697 PMCID: PMC7297544 DOI: 10.1063/4.0000014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
Structural details of thermoresponsive, cationically poly(N-iso-propylacrylamide-co-methacrylamido propyl trimethyl ammonium chloride) microgels and the influence of the anionic electrolyte polystyrene sulfonate (PSS) on the internal structure and dynamics of the cationic microgels have been studied with a combination of small angle neutron scattering (SANS) and neutron spin echo (NSE) spectroscopy. While SANS can yield information on the overall size of the particles and on the typical correlation length inside the particles, studying the segmental polymer dynamics with NSE gives access to more internal details, which only appear due to their effect on the polymer motion. The segmental dynamics of the microgels studied in this paper is to a large extent suppressed by the PSS additive. Possible scenarios of the influence of the polyanions on the microgel structure and dynamics are discussed.
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Affiliation(s)
- S. Pasini
- Forschungszentrum Jülich GmbH, JCNS at Heinz Maier-Leibnitz Zentrum, Lichtenbergstraße 1, 85747 Garching, Germany
| | - S. Maccarrone
- Forschungszentrum Jülich GmbH, JCNS at Heinz Maier-Leibnitz Zentrum, Lichtenbergstraße 1, 85747 Garching, Germany
| | - N. K. Székely
- Forschungszentrum Jülich GmbH, JCNS at Heinz Maier-Leibnitz Zentrum, Lichtenbergstraße 1, 85747 Garching, Germany
| | - L. R. Stingaciu
- NScD, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A. P. H. Gelissen
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany
| | - W. Richtering
- Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen and JARA-SOFT 52056 Aachen, Germany
| | - M. Monkenbusch
- Jülich Centre for Neutron Science (JCNS) & Institute for Complex Systems (ICS), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - O. Holderer
- Forschungszentrum Jülich GmbH, JCNS at Heinz Maier-Leibnitz Zentrum, Lichtenbergstraße 1, 85747 Garching, Germany
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19
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Willendrup PK, Lefmann K. McStas (i): Introduction, use, and basic principles for ray-tracing simulations. JOURNAL OF NEUTRON RESEARCH 2020. [DOI: 10.3233/jnr-190108] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Peter Kjær Willendrup
- Department of Physics, Technical University of Denmark, Denmark. E-mail:
- Data Management and Software Center, European Spallation Source, Denmark
| | - Kim Lefmann
- Niels Bohr Institute, University of Copenhagen, Denmark. E-mail:
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20
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Using neutron methods SANS and PGAA to study evolution of structure and composition of alkali-doped polybenzimidazole membranes. J Memb Sci 2019. [DOI: 10.1016/j.memsci.2019.01.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Temperature-responsive star-shaped poly(2-ethyl-2-oxazoline) and poly(2-isopropyl-2-oxazoline) with central thiacalix[4]arene fragments: structure and properties in solutions. Colloid Polym Sci 2019. [DOI: 10.1007/s00396-018-4458-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Structural and molecular response in cyclodextrin-based pH-sensitive hydrogels by the joint use of Brillouin, UV Raman and Small Angle Neutron Scattering techniques. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.08.141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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23
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Local Deformation and Mn-C Short-Range Ordering in a High-Mn Fe-18Mn-0.6C Steel. METALS 2018. [DOI: 10.3390/met8050292] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Houston JE, Brandl G, Drochner M, Kemmerling G, Engels R, Papagiannopoulos A, Sarter M, Stadler A, Radulescu A. The high-intensity option of the SANS diffractometer KWS-2 at JCNS - characterization and performance of the new multi-megahertz detection system. J Appl Crystallogr 2018; 51:323-336. [PMID: 29657566 PMCID: PMC5884387 DOI: 10.1107/s1600576718004132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 03/12/2018] [Indexed: 11/16/2022] Open
Abstract
A new detection system based on an array of 3He tubes and innovative fast detection electronics has been installed on the high-intensity small-angle neutron scattering (SANS) diffractometer KWS-2 operated by the Jülich Centre for Neutron Science (JCNS) at the Heinz Meier-Leibnitz Zentrum in Garching, Germany. The new detection system is composed of 18 eight-pack modules of 3He tubes that work independently of one another (each unit has its own processor and electronics). To improve the read-out characteristics and reduce the noise, the detection electronics are mounted in a closed case on the rear of the 3He tubes' frame. The tubes' efficiency is about 85% (for λ = 5 Å) and the resolution slightly better than 8 mm. The new detection system is characterized by a dead-time constant of 3.3 µs per tube and an overall count rate as high as 6 MHz at 10% dead-time loss. Compared with the old detector this is an improvement by a factor of 60. The much higher count rate will shorten the measurement times and thus increase the number of experiments possible in a given time period by the optimal use of the high flux of up to 2 × 108 n cm-2 s-1 at the sample position. Combined with the event-mode operation capability, this will enable new scientific opportunities in the field of structural investigations of small soft-matter and biological systems. The implementation of the detector in the high-intensity concept on KWS-2, its characterization and its performance based on test experiments are reported in this paper.
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Affiliation(s)
- Judith Elizabeth Houston
- Jülich Centre for Neutron Science at Maier Leibnitz-Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching 85747, Germany
| | - Georg Brandl
- Jülich Centre for Neutron Science at Maier Leibnitz-Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching 85747, Germany
| | - Matthias Drochner
- Jülich Centre for Neutron Science (JCNS-2), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Strasse, Jülich 52428, Germany
| | - Günter Kemmerling
- Jülich Centre for Neutron Science (JCNS-2), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Strasse, Jülich 52428, Germany
| | - Ralf Engels
- Jülich Centre for Neutron Science (JCNS-2), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Strasse, Jülich 52428, Germany
| | - Aristeidis Papagiannopoulos
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, Athens 11635, Greece
| | - Mona Sarter
- Institute of Physics (IA), Rheinisch Westfälische Technische Hochschule Aachen (RWTH Aachen), Templergraben 55, Aachen 52056, Germany
| | - Andreas Stadler
- Jülich Centre for Neutron Science (JCNS-1), Institute for Complex Systems (ICS), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Strasse, Jülich 52428, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science at Maier Leibnitz-Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching 85747, Germany
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Successful reprogramming of cellular protein production through mRNA delivered by functionalized lipid nanoparticles. Proc Natl Acad Sci U S A 2018; 115:E3351-E3360. [PMID: 29588418 PMCID: PMC5899464 DOI: 10.1073/pnas.1720542115] [Citation(s) in RCA: 260] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
mRNA treatments represent an exciting approach to cure diseases that cannot be tackled with current therapeutics. However, the delivery of mRNA to target cells remains a challenge, but among the existing alternatives, lipid nanoparticles (LNPs) offer a promising answer to this. Here we determine the structure of LNPs encapsulating mRNA, consisting of a lipid mixture already evaluated in clinical trials. We show that the lipids are not homogeneously distributed across the LNP, and one of the lipids is localized mainly at its surface. The structural information enabled us to design LNPs that successfully modify intracellular protein production in two clinically relevant cell types. Our findings and approach provide a framework for understanding and optimizing vehicles for mRNA delivery. The development of safe and efficacious gene vectors has limited greatly the potential for therapeutic treatments based on messenger RNA (mRNA). Lipid nanoparticles (LNPs) formed by an ionizable cationic lipid (here DLin-MC3-DMA), helper lipids (distearoylphosphatidylcholine, DSPC, and cholesterol), and a poly(ethylene glycol) (PEG) lipid have been identified as very promising delivery vectors of short interfering RNA (siRNA) in different clinical phases; however, delivery of high-molecular weight RNA has been proven much more demanding. Herein we elucidate the structure of hEPO modified mRNA-containing LNPs of different sizes and show how structural differences affect transfection of human adipocytes and hepatocytes, two clinically relevant cell types. Employing small-angle scattering, we demonstrate that LNPs have a disordered inverse hexagonal internal structure with a characteristic distance around 6 nm in presence of mRNA, whereas LNPs containing no mRNA do not display this structure. Furthermore, using contrast variation small-angle neutron scattering, we show that one of the lipid components, DSPC, is localized mainly at the surface of mRNA-containing LNPs. By varying LNP size and surface composition we demonstrate that both size and structure have significant influence on intracellular protein production. As an example, in both human adipocytes and hepatocytes, protein expression levels for 130 nm LNPs can differ as much as 50-fold depending on their surface characteristics, likely due to a difference in the ability of LNP fusion with the early endosome membrane. We consider these discoveries to be fundamental and opening up new possibilities for rational design of synthetic nanoscopic vehicles for mRNA delivery.
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Glavic A, Stahn J. HEKATE-A novel grazing incidence neutron scattering concept for the European Spallation Source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:035105. [PMID: 29604763 DOI: 10.1063/1.5004658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Structure and magnetism at surfaces and buried interfaces on the nanoscale can only be accessed by few techniques, one of which is grazing incidence neutron scattering. While the technique has its strongest limitation in a low signal and large background, due to the low scattering probability and need for high resolution, it can be expected that the high intensity of the European Spallation Source in Lund, Sweden, will make many more such studies possible, warranting a dedicated beamline for this technique. We present an instrument concept, Highly Extended K range And Tunable Experiment (HEKATE), for surface scattering that combines the advantages of two Selene neutron guides with unique capabilities of spatially separated distinct wavelength frames. With this combination, it is not only possible to measure large specular reflectometry ranges, even on free liquid surfaces, but also to use two independent incident beams with tunable sizes and resolutions that can be optimized for the specifics of the investigated samples. Further the instrument guide geometry is tuned for reduction of high energy particle background and only uses low to moderate supermirror coatings for high reliability and affordable cost.
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Affiliation(s)
- Artur Glavic
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Jochen Stahn
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, Villigen PSI, Switzerland
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Delisavva F, Uchman M, Štěpánek M, Kereïche S, Hordyjewicz-Baran Z, Appavou MS, Procházka K. Coassembly of Gemini Surfactants with Double Hydrophilic Block Polyelectrolytes Leading to Complex Nanoassemblies. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01330] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Foteini Delisavva
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague 2, Czech Republic
| | - Mariusz Uchman
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague 2, Czech Republic
| | - Miroslav Štěpánek
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague 2, Czech Republic
| | - Sami Kereïche
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague 2, Czech Republic
- Institute
of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Purkynie Ustav,
Albetov 4, 12 801 Prague, Czech Republic
| | - Zofia Hordyjewicz-Baran
- Institute of Heavy
Organic Synthesis “Blachownia”, Energetykow 9, 47-225 Kedzierzyn-Kozle, Poland
| | - Marie-Sousai Appavou
- Jülich
Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum
(MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Karel Procházka
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague 2, Czech Republic
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Changes within the stabilizing layer of ZnO nanoparticles upon washing. J Colloid Interface Sci 2017; 504:356-362. [PMID: 28582753 DOI: 10.1016/j.jcis.2017.05.059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/17/2017] [Accepted: 05/18/2017] [Indexed: 10/19/2022]
Abstract
ZnO nanoparticles (NPs) are highly relevant for various industrial applications, however, after synthesis of the NPs residual chemicals need to be removed from the colloidal raw product by washing, as they may influence the performance of the final device. In the present study we focus on the effect of washing by antisolvent flocculation with subsequent redispersion of the NPs on the stabilizing acetate shell. Purification of the ZnO nanoparticles is reported to be optimal with respect to zeta potential that has a maximum after one washing cycle. In this work, we will shed light on this observation using small angle X-ray and neutron scattering (SAXS, SANS) by demonstrating that after the first washing cycle the content of acetate in the ligand shell around the ZnO NPs increases. In detail, it was observed that the diffuse acetate shell shrinks to the size of a monolayer upon washing but the acetate content of this monolayer is higher than within the diffuse shell of the particles of the native dispersion. A second washing cycle reduces the acetate concentration within the stabilizing shell and the stability of the dispersion drops accordingly. After another (third) washing cycle strong agglomeration was observed for all investigated samples.
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Ivanova O, Lüke W, Majerus A, Krutyeva M, Szekely N, Pyckhout-Hintzen W, Appavou MS, Monkenbusch M, Zorn R, Lehnert W, Holderer O. Influence of morphology on physical properties of poly(2,5-benzimidazole) membranes. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2017.03.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Wolff M, Zhang-Haagen B, Decker C, Barz B, Schneider M, Biehl R, Radulescu A, Strodel B, Willbold D, Nagel-Steger L. Aβ42 pentamers/hexamers are the smallest detectable oligomers in solution. Sci Rep 2017; 7:2493. [PMID: 28559586 PMCID: PMC5449387 DOI: 10.1038/s41598-017-02370-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 04/11/2017] [Indexed: 12/14/2022] Open
Abstract
Amyloid β (Aβ) oligomers may play a decisive role in Alzheimer's disease related neurodegeneration, but their structural properties are poorly understood. In this report, sedimentation velocity centrifugation, small angle neutron scattering (SANS) and molecular modelling were used to identify the small oligomeric species formed by the 42 amino acid residue long isoform of Aβ (Aβ42) in solution, characterized by a sedimentation coefficient of 2.56 S, and a radius of gyration between 2 and 4 nm. The measured sedimentation coefficient is in close agreement with the sedimentation coefficient calculated for Aβ42 hexamers using MD simulations at µM concentration. To the best of our knowledge this is the first report detailing the Aβ42 oligomeric species by SANS measurements. Our results demonstrate that the smallest detectable species in solution are penta- to hexamers. No evidences for the presence of dimers, trimers or tetramers were found, although the existence of those Aβ42 oligomers at measurable quantities had been reported frequently.
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Affiliation(s)
- Martin Wolff
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
- Physikalische Biochemie, University Potsdam, 14476, Golm, Germany
| | - Bo Zhang-Haagen
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
- Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Christina Decker
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Bogdan Barz
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Mario Schneider
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
| | - Ralf Biehl
- Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Forschungszentrum Jülich, 52425, Jülich, Germany
- Jülich Centre for Neutron Science, Outstation at MLZ (JCNS-MLZ), Forschungszentrum Jülich, 85747, Garching, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science, Outstation at MLZ (JCNS-MLZ), Forschungszentrum Jülich, 85747, Garching, Germany
| | - Birgit Strodel
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Dieter Willbold
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Luitgard Nagel-Steger
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany.
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425, Jülich, Germany.
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Russo Krauss I, Imperatore R, De Santis A, Luchini A, Paduano L, D'Errico G. Structure and dynamics of cetyltrimethylammonium chloride-sodium dodecylsulfate (CTAC-SDS) catanionic vesicles: High-value nano-vehicles from low-cost surfactants. J Colloid Interface Sci 2017; 501:112-122. [PMID: 28437699 DOI: 10.1016/j.jcis.2017.04.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022]
Abstract
HYPOTHESIS Catanionic vesicles based on large-scale produced surfactants represent a promising platform for the design of innovative, effective and relatively inexpensive nano-vehicles for a variety of actives. Structural, dynamic and functional behavior of these aggregates is finely tuned by the molecular features of their components and can be opportunely tailored for their applications as drug carriers. EXPERIMENTS Here we investigate the aggregates formed by CTAC and SDS, two of the most diffused surfactants, by means of Dynamic Light Scattering, Small Angle Neutron Scattering and Electron Paramagnetic Resonance spectroscopy (EPR). The exploitation of these aggregates as nano-vehicles is explored using the poorly water-soluble antioxidant trans-resveratrol (t-RESV), testing t-RESV solubility and antioxidant activity by means of UV, fluorescence spectroscopy and EPR. FINDINGS The presence of a large stability region of catanionic vesicles on the CTAC-rich side of the phase diagram is highlighted and interpreted in terms of the mismatch between the lengths of the surfactant tails and of first reported effects of the chloride counterions. CTAC-SDS vesicles massively solubilize t-RESV, which in catanionic vesicles exerts a potent antioxidant and radical-scavenging activity. This behavior arises from the positioning of the active at the surface of the vesicular aggregates thus being sufficiently exposed to the external medium.
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Affiliation(s)
- Irene Russo Krauss
- Department of Chemical Sciences, University of Naples ''Federico II'', Complesso di Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy; CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), via della Lastruccia 3, I-50019 Florence, Italy
| | - Riccardo Imperatore
- Department of Chemical Sciences, University of Naples ''Federico II'', Complesso di Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy; CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), via della Lastruccia 3, I-50019 Florence, Italy
| | - Augusta De Santis
- Department of Chemical Sciences, University of Naples ''Federico II'', Complesso di Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy; CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), via della Lastruccia 3, I-50019 Florence, Italy
| | - Alessandra Luchini
- Department of Chemical Sciences, University of Naples ''Federico II'', Complesso di Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy; CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), via della Lastruccia 3, I-50019 Florence, Italy; Institut Laue-Langevin, BP 156, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Luigi Paduano
- Department of Chemical Sciences, University of Naples ''Federico II'', Complesso di Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy; CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), via della Lastruccia 3, I-50019 Florence, Italy
| | - Gerardino D'Errico
- Department of Chemical Sciences, University of Naples ''Federico II'', Complesso di Monte S. Angelo, Via Cinthia, I-80126 Naples, Italy; CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), via della Lastruccia 3, I-50019 Florence, Italy.
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Sill C, Biehl R, Hoffmann B, Radulescu A, Appavou MS, Farago B, Merkel R, Richter D. Structure and domain dynamics of human lactoferrin in solution and the influence of Fe(III)-ion ligand binding. BMC BIOPHYSICS 2016; 9:7. [PMID: 27822363 PMCID: PMC5095980 DOI: 10.1186/s13628-016-0032-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/25/2016] [Indexed: 11/17/2022]
Abstract
Background Human lactoferrin is an iron-binding protein of the innate immune system consisting of two connected lobes, each with a binding site located in a cleft. The clefts in each lobe undergo a hinge movement from open to close when Fe3+ is present in the solution and can be bound. The binding mechanism was assumed to relate on thermal domain fluctuations of the cleft domains prior to binding. We used Small Angle Neutron Scattering and Neutron Spin Echo Spectroscopy to determine the lactoferrin structure and domain dynamics in solution. Results When Fe3+ is present in solution interparticle interactions change from repulsive to attractive in conjunction with emerging metas aggregates, which are not observed without Fe3+. The protein form factor shows the expected change due to lobe closing if Fe3+ is present. The dominating motions of internal domain dynamics with relaxation times in the 30–50 ns range show strong bending and stretching modes with a steric suppressed torsion, but are almost independent of the cleft conformation. Thermally driven cleft closing motions of relevant amplitude are not observed if the cleft is open. Conclusion The Fe3+ binding mechanism is not related to thermal equilibrium fluctuations closing the cleft. A likely explanation may be that upon entering the cleft the iron ion first binds weakly which destabilizes and softens the hinge region and enables large fluctuations that then close the cleft resulting in the final formation of the stable iron binding site and, at the same time, stable closed conformation. Electronic supplementary material The online version of this article (doi:10.1186/s13628-016-0032-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Clemens Sill
- JCNS-1 & ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt Strasse, 52425 Jülich, Germany
| | - Ralf Biehl
- JCNS-1 & ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt Strasse, 52425 Jülich, Germany
| | - Bernd Hoffmann
- ICS-7, Forschungszentrum Jülich GmbH, Leo-Brandt Strasse, 52425 Jülich, Germany
| | - Aurel Radulescu
- JCNS-MLZ, Forschungszentrum Jülich GmbH Outstation at MLZ, Lichtenbergstraße, 1 85747 Garching, Germany
| | - Marie-Sousai Appavou
- JCNS-MLZ, Forschungszentrum Jülich GmbH Outstation at MLZ, Lichtenbergstraße, 1 85747 Garching, Germany
| | - Bela Farago
- Institute Laue-Langevin, CS 20156, 38042 Grenoble, France
| | - Rudolf Merkel
- ICS-7, Forschungszentrum Jülich GmbH, Leo-Brandt Strasse, 52425 Jülich, Germany
| | - Dieter Richter
- JCNS-1 & ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt Strasse, 52425 Jülich, Germany
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Composite particles formed by complexation of poly(methacrylic acid) — stabilized magnetic fluid with chitosan: Magnetic material for bioapplications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 67:486-492. [DOI: 10.1016/j.msec.2016.05.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/31/2016] [Accepted: 05/04/2016] [Indexed: 11/17/2022]
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Staropoli M, Raba A, Hövelmann CH, Krutyeva M, Allgaier J, Appavou MS, Keiderling U, Stadler FJ, Pyckhout-Hintzen W, Wischnewski A, Richter D. Hydrogen Bonding in a Reversible Comb Polymer Architecture: A Microscopic and Macroscopic Investigation. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00978] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Mariapaola Staropoli
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
| | - Andreas Raba
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
| | - Claas H. Hövelmann
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
| | - Margarita Krutyeva
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
| | - Jürgen Allgaier
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
| | | | - Uwe Keiderling
- Helmholtz-Zentrum Berlin für Materialien and Energie, 14109 Berlin, Germany
| | - Florian J. Stadler
- Nanshan
District Key Lab for Biopolymers and Safety Evaluation, College of
Materials Science and Engineering and Department of Optoelectronic
Engineering, Shenzhen University, Shenzhen, Guangdong China
| | - Wim Pyckhout-Hintzen
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
| | - Andreas Wischnewski
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
| | - Dieter Richter
- JCNS-1
and ICS-1, Forschungszentrum Jülich GmbH, Leo-Brandt-Straße, 52425 Jülich, Germany
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Systematic Limitations in Concentration Analysis via Anomalous Small-Angle X-ray Scattering in the Small Structure Limit. Polymers (Basel) 2016; 8:polym8030085. [PMID: 30979177 PMCID: PMC6432554 DOI: 10.3390/polym8030085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 11/17/2022] Open
Abstract
Anomalous small angle scattering measurements have been applied to diluted solutions of anionic polyacrylates decorated by specifically-interacting Pb2+ cations, revealing partial collapse of the polyacrylate into pearl-like subdomains with a size on the order of a few nanometers. From the pure-resonant scattering contribution of the Pb2+ cations, and from subsequent analysis of the resonant-invariant, the amount of Pb2+ cations condensed onto the polyanions with respect to the total amount of Pb2+ cations in the solvent was estimated. In order to scrutinize systematic limitations in the determination of the chemical concentrations of resonant scattering counterions in the collapsed phase, Monte Carlo simulations have been performed. The simulations are based on structural confinements at variable size in the range of few nanometers, which represent the collapsed subdomains in the polyanions. These confinements were gradually filled to a high degree of the volume fraction with resonant scattering counterions giving access to a resonant-invariant at a variable degree of filling. The simulations revealed in the limit of small structures a significant underestimation of the true degree of filling of the collapsed subdomains when determining chemical concentrations of Pb2+ cations from the resonant invariant.
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Zhao Y, Yoshida M, Oshima T, Koizumi S, Rikukawa M, Szekely N, Radulescu A, Richter D. Elucidation of the morphology of the hydrocarbon multi-block copolymer electrolyte membranes for proton exchange fuel cells. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.01.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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37
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Zhang-Haagen B, Biehl R, Nagel-Steger L, Radulescu A, Richter D, Willbold D. Monomeric Amyloid Beta Peptide in Hexafluoroisopropanol Detected by Small Angle Neutron Scattering. PLoS One 2016; 11:e0150267. [PMID: 26919121 PMCID: PMC4769228 DOI: 10.1371/journal.pone.0150267] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/11/2016] [Indexed: 01/17/2023] Open
Abstract
Small proteins like amyloid beta (Aβ) monomers are related to neurodegenerative disorders by aggregation to insoluble fibrils. Small angle neutron scattering (SANS) is a nondestructive method to observe the aggregation process in solution. We show that SANS is able to resolve monomers of small molecular weight like Aβ for aggregation studies. We examine Aβ monomers after prolonged storing in d-hexafluoroisopropanol (dHFIP) by using SANS and dynamic light scattering (DLS). We determined the radius of gyration from SANS as 1.0±0.1 nm for Aβ1–40 and 1.6±0.1 nm for Aβ1–42 in agreement with 3D NMR structures in similar solvents suggesting a solvent surface layer with 5% increased density. After initial dissolution in dHFIP Aβ aggregates sediment with a major component of pure monomers showing a hydrodynamic radius of 1.8±0.3 nm for Aβ1–40 and 3.2±0.4 nm for Aβ1–42 including a surface layer of dHFIP solvent molecules.
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Affiliation(s)
- Bo Zhang-Haagen
- Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Research Centre Jülich, Jülich, Germany
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Ralf Biehl
- Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Research Centre Jülich, Jülich, Germany
- * E-mail:
| | - Luitgard Nagel-Steger
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Research Centre Jülich, Jülich, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science, Outstation at MLZ (JCNS-MLZ), Research Centre Jülich, Garching, Germany
| | - Dieter Richter
- Jülich Centre for Neutron Science & Institute of Complex Systems, Neutron Scattering (JCNS-1&ICS-1), Research Centre Jülich, Jülich, Germany
| | - Dieter Willbold
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
- Institute of Complex Systems, Structural Biochemistry (ICS-6), Research Centre Jülich, Jülich, Germany
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Dahdal Y, Pipich V, Rapaport H, Oren Y, Kasher R, Schwahn D. Small-angle neutron scattering studies of alginate as biomineralizing agent and scale initiator. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Schindler T, Schmiele M, Schmutzler T, Kassar T, Segets D, Peukert W, Radulescu A, Kriele A, Gilles R, Unruh T. A Combined SAXS/SANS Study for the in Situ Characterization of Ligand Shells on Small Nanoparticles: The Case of ZnO. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:10130-10136. [PMID: 26327573 DOI: 10.1021/acs.langmuir.5b02198] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
ZnO nanoparticles (NPs) have great potential for their use in, e.g., thin film solar cells due to their electro-optical properties adjustable on the nanoscale. Therefore, the production of well-defined NPs is of major interest. For a targeted production process, the knowledge of the stabilization layer of the NPs during and after their formation is of particular importance. For the study of the stabilizer layer of ZnO NPs prepared in a wet chemical synthesis from zinc acetate, only ex situ studies have been performed so far. An acetate layer bound to the surface of the dried NPs was found; however, an in situ study which addresses the stabilizing layer surrounding the NPs in a native dispersion was missing. By the combination of small angle scattering with neutrons and X-rays (SANS and SAXS) for the same sample, we are now able to observe the acetate shell in situ for the first time. In addition, the changes of this shell could be followed during the ripening process for different temperatures. With increasing size of the ZnO core (d(core)) the surrounding shell (d(shell)) becomes larger, and the acetate concentration within the shell is reduced. For all samples, the shell thickness was found to be larger than the maximum extension of an acetate molecule with acetate concentrations within the shell below 50 vol %. Thus, there is not a monolayer of acetate molecules that covers the NPs but rather a swollen shell of acetate ions. This shell is assumed to hinder the growth of the NPs to larger macrostructures. In addition, we found that the partition coefficient μ between acetate in the shell surrounding the NPs and the total amount of acetate in the solution is about 10% which is in good agreement with ex situ data determined by thermogravimetric analysis.
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Affiliation(s)
- T Schindler
- Chair of Crystallography and Structural Physics, Friedrich-Alexander-Universät Erlangen-Nürnberg , Staudtstraße 3, 91058 Erlangen, Germany
| | - M Schmiele
- Chair of Crystallography and Structural Physics, Friedrich-Alexander-Universät Erlangen-Nürnberg , Staudtstraße 3, 91058 Erlangen, Germany
| | - T Schmutzler
- Chair of Crystallography and Structural Physics, Friedrich-Alexander-Universät Erlangen-Nürnberg , Staudtstraße 3, 91058 Erlangen, Germany
| | - T Kassar
- Chair of Crystallography and Structural Physics, Friedrich-Alexander-Universät Erlangen-Nürnberg , Staudtstraße 3, 91058 Erlangen, Germany
| | - D Segets
- Institute of Particle Technology, Friedrich-Alexander-Universät Erlangen-Nürnberg , Cauerstraße 4, 91058 Erlangen, Germany
| | - W Peukert
- Institute of Particle Technology, Friedrich-Alexander-Universät Erlangen-Nürnberg , Cauerstraße 4, 91058 Erlangen, Germany
| | - A Radulescu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), Outstation at MLZ, 85747 Garching, Germany
| | - A Kriele
- Helmholtz Zentrum Geesthacht, Max-Plank-Straße 1, 21502 Geesthacht, Germany
| | - R Gilles
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München , 85747 Garching, Germany
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Peterson VK, Papadakis CM. Functional materials analysis using in situ and in operando X-ray and neutron scattering. IUCRJ 2015; 2:292-304. [PMID: 25866665 PMCID: PMC4392421 DOI: 10.1107/s2052252514026062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 11/27/2014] [Indexed: 05/04/2023]
Abstract
In situ and in operando studies are commonplace and necessary in functional materials research. This review highlights recent developments in the analysis of functional materials using state-of-the-art in situ and in operando X-ray and neutron scattering and analysis. Examples are given covering a number of important materials areas, alongside a description of the types of information that can be obtained and the experimental setups used to acquire them.
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Affiliation(s)
- Vanessa K. Peterson
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Christine M. Papadakis
- Physik-Department, Fachgebiet Physik weicher Materie, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
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Feoktystov AV, Frielinghaus H, Di Z, Jaksch S, Pipich V, Appavou MS, Babcock E, Hanslik R, Engels R, Kemmerling G, Kleines H, Ioffe A, Richter D, Brückel T. KWS-1 high-resolution small-angle neutron scattering instrument at JCNS: current state. J Appl Crystallogr 2015. [DOI: 10.1107/s1600576714025977] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The KWS-1 small-angle neutron scattering (SANS) instrument operated by the Jülich Centre for Neutron Science (JCNS) at the research reactor FRM II of the Heinz Maier-Leibnitz Zentrum in Garching near Munich has been recently upgraded. The KWS-1 instrument was updated, from its active collimation apertures to the detector cabling. Most of the parts of the instrument were installed for the first time, including a broadband polarizer, a large-cross-section radio-frequency spin flipper, a chopper and neutron lenses. A custom-designed hexapod in the sample position allows heavy loads and precise sample positioning in the beam for conventional SANS experiments as well as for grazing-incidence SANS under applied magnetic field. With the foreseenin situpolarization analysis the main scientific topic of the instrument tends towards magnetism. The performance of the polarizer and flipper was checked with a polarized3He cell at the sample position. The results of these checks and a comparison of test measurements on a ferrofluid in a magnetic field with polarized and nonpolarized neutrons are presented.
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Schmiele M, Schindler T, Unruh T, Busch S, Morhenn H, Westermann M, Steiniger F, Radulescu A, Lindner P, Schweins R, Boesecke P. Structural characterization of the phospholipid stabilizer layer at the solid-liquid interface of dispersed triglyceride nanocrystals with small-angle x-ray and neutron scattering. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:062316. [PMID: 23848684 DOI: 10.1103/physreve.87.062316] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Indexed: 06/02/2023]
Abstract
Dispersions of crystalline nanoparticles with at least one sufficiently large unit cell dimension can give rise to Bragg reflections in the small-angle scattering range. If the nanocrystals possess only a small number of unit cells along these particular crystallographic directions, the corresponding Bragg reflections will be broadened. In a previous study of phospholipid stabilized dispersions of β-tripalmitin platelets [Unruh, J. Appl. Crystallogr. 40, 1008 (2007)], the x-ray powder pattern simulation analysis (XPPSA) was developed. The XPPSA method facilitates the interpretation of the rather complicated small-angle x-ray scattering (SAXS) curves of such dispersions of nanocrystals. The XPPSA method yields the distribution function of the platelet thicknesses and facilitates a structural characterization of the phospholipid stabilizer layer at the solid-liquid interface between the nanocrystals and the dispersion medium from the shape of the broadened 001 Bragg reflection. In this contribution an improved and extended version of the XPPSA method is presented. The SAXS and small-angle neutron scattering patterns of dilute phospholipid stabilized tripalmitin dispersions can be reproduced on the basis of a consistent simulation model for the particles and their phospholipid stabilizer layer on an absolute scale. The results indicate a surprisingly flat arrangement of the phospholipid molecules in the stabilizer layer with a total thickness of only 12 Å. The stabilizer layer can be modeled by an inner shell for the fatty acid chains and an outer shell including the head groups and additional water. The experiments support a dense packing of the phospholipid molecules on the nanocrystal surfaces rather than isolated phospholipid domains.
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Affiliation(s)
- Martin Schmiele
- Professur für Nanomaterialcharakterisierung (Streumethoden), Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 3, 91058 Erlangen, Germany
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