1
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Li R, Kirkensgaard JJK, Corredig M. Structural evolution of pea-derived albumins during pH and heat treatment studied with light and X-ray scattering. Food Res Int 2024; 186:114380. [PMID: 38729734 DOI: 10.1016/j.foodres.2024.114380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/15/2024] [Accepted: 04/17/2024] [Indexed: 05/12/2024]
Abstract
Pea albumins are found in the side stream during the isolation of pea proteins. They are soluble at acidic pH and have functional properties which differ from their globulin counterparts. In this study, we have investigated the aggregation and structural changes occurring to pea albumins under different environmental conditions, using a combination of size-exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALS) and small-angle X-ray scattering (SAXS). Albumins were extracted from a dry fractionated pea protein concentrate by precipitating the globulin fraction at acidic pH. The albumins were then studied at different pH (3, 4, 4.5, 7, 7.5, and 8) values. The effect of heating at 90 °C for 1, 3, and 5 min on their structural changes was investigated using SAXS. In addition, size exclusion of the albumins showed 4 distinct populations, depending on pH and heating conditions, with two large aggregates peaks (∼250 kDa): a dimer peak (∼24 kDa) containing predominantly pea albumin 2 (PA2), and a monomer peak of a molar mass of about 12 kDa (PA1). X-ray scattering intensities as a function of q were modeled as polydisperse spheres, and their aggregation was followed as a function of heating time. Albumins was most stable at pH 3, showing no aggregation during heat treatment. While albumins at pH 7.5 and 8 showed aggregation after heating, solutions at pH 4, 4.5, and 7 already contained aggregates even before heating. This work provides new knowledge on the overall structural development of albumins under different environmental conditions, improving our ability to employ these as future ingredients in foods.
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Affiliation(s)
- Ruifen Li
- Department of Food Science & CiFood Center for Innovative Food Research, Aarhus University, Agro Food Park 48, 8200 Aarhus N, Denmark.
| | - Jacob J K Kirkensgaard
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, DK-1958 Frederiksberg C, Denmark; Niels Bohr Institute, Universitetsparken 5, 2100 København Ø, Denmark
| | - Milena Corredig
- Department of Food Science & CiFood Center for Innovative Food Research, Aarhus University, Agro Food Park 48, 8200 Aarhus N, Denmark
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2
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Jessop AL, Millsteed AJ, Kirkensgaard JJK, Shaw J, Clode PL, Schröder-Turk GE. Composite material in the sea urchin Cidaris rugosa: ordered and disordered micrometre-scale bicontinuous geometries. J R Soc Interface 2024; 21:20230597. [PMID: 38471532 PMCID: PMC10932713 DOI: 10.1098/rsif.2023.0597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
The sponge-like biomineralized calcite materials found in echinoderm skeletons are of interest in terms of both structure formation and biological function. Despite their crystalline atomic structure, they exhibit curved interfaces that have been related to known triply periodic minimal surfaces. Here, we investigate the endoskeleton of the sea urchin Cidaris rugosa that has long been known to form a microstructure related to the Primitive surface. Using X-ray tomography, we find that the endoskeleton is organized as a composite material consisting of domains of bicontinuous microstructures with different structural properties. We describe, for the first time, the co-occurrence of ordered single Primitive and single Diamond structures and of a disordered structure within a single skeletal plate. We show that these structures can be distinguished by structural properties including solid volume fraction, trabeculae width and, to a lesser extent, interface area and mean curvature. In doing so, we present a robust method that extracts interface areas and curvature integrals from voxelized datasets using the Steiner polynomial for parallel body volumes. We discuss these very large-scale bicontinuous structures in the context of their function, formation and evolution.
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Affiliation(s)
- Anna-Lee Jessop
- School of Mathematics, Statistics, Chemistry and Physics, Murdoch University, Murdoch, Australia
| | - Allan J. Millsteed
- School of Mathematics, Statistics, Chemistry and Physics, Murdoch University, Murdoch, Australia
| | - Jacob J. K. Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Kobenhavn, Denmark
- Department of Food Science, University of Copenhagen, Kobenhavn, Denmark
| | - Jeremy Shaw
- Centre for Microscopy, Characterisation, and Analysis, University of Western Australia, Perth, Australia
| | - Peta L. Clode
- Centre for Microscopy, Characterisation, and Analysis, University of Western Australia, Perth, Australia
- School of Biological Sciences, University of Western Australia, Perth, Australia
| | - Gerd E. Schröder-Turk
- School of Mathematics, Statistics, Chemistry and Physics, Murdoch University, Murdoch, Australia
- Research School of Physics, The Australian National University, Canberra, Australia
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3
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Krog LS, Kirkensgaard JJK, Foderà V, Boyd BJ, Be Rziņš KR. Application of Low-Frequency Raman Spectroscopy to Probe Dynamics of Lipid Mesophase Transformations upon Hydration. J Phys Chem B 2023; 127:3223-3230. [PMID: 36999811 DOI: 10.1021/acs.jpcb.2c08150] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Abstract
Low-frequency Raman (LFR) spectroscopy is presented as a viable tool for studying the hydration characteristics of lyotropic liquid crystal systems herein. Monoolein was used as a model compound, and its structural changes were probed both in situ and ex situ which enabled a comparison between different hydration states. A custom-built instrumental configuration allowed the advantages of LFR spectroscopy to be utilized for dynamic hydration analysis. On the other hand, static measurements of equilibrated systems (i.e., with varied aqueous content) showcased the structural sensitivity of LFR spectroscopy. The subtle differences not intuitively observed between similar self-assembled architectures were distinguished by chemometric analysis that directly correlated with the results from small-angle X-ray scattering (SAXS), which is the current "gold standard" method for determining the structure of such materials.
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Affiliation(s)
- Lasse S Krog
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Jacob J K Kirkensgaard
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, Frederiksberg C 1958, Denmark
- Niels Bohr Institute, Faculty of Science, University of Copenhagen, Universitetsparken 5, Copenhagen 2100, Denmark
| | - Vito Foderà
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Ben J Boyd
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville Victoria 3052, Australia
| | - Ka Rlis Be Rziņš
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
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4
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Schamberger B, Ziege R, Anselme K, Ben Amar M, Bykowski M, Castro APG, Cipitria A, Coles RA, Dimova R, Eder M, Ehrig S, Escudero LM, Evans ME, Fernandes PR, Fratzl P, Geris L, Gierlinger N, Hannezo E, Iglič A, Kirkensgaard JJK, Kollmannsberger P, Kowalewska Ł, Kurniawan NA, Papantoniou I, Pieuchot L, Pires THV, Renner LD, Sageman-Furnas AO, Schröder-Turk GE, Sengupta A, Sharma VR, Tagua A, Tomba C, Trepat X, Waters SL, Yeo EF, Roschger A, Bidan CM, Dunlop JWC. Curvature in Biological Systems: Its Quantification, Emergence, and Implications across the Scales. Adv Mater 2023; 35:e2206110. [PMID: 36461812 DOI: 10.1002/adma.202206110] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/22/2022] [Indexed: 06/17/2023]
Abstract
Surface curvature both emerges from, and influences the behavior of, living objects at length scales ranging from cell membranes to single cells to tissues and organs. The relevance of surface curvature in biology is supported by numerous experimental and theoretical investigations in recent years. In this review, first, a brief introduction to the key ideas of surface curvature in the context of biological systems is given and the challenges that arise when measuring surface curvature are discussed. Giving an overview of the emergence of curvature in biological systems, its significance at different length scales becomes apparent. On the other hand, summarizing current findings also shows that both single cells and entire cell sheets, tissues or organisms respond to curvature by modulating their shape and their migration behavior. Finally, the interplay between the distribution of morphogens or micro-organisms and the emergence of curvature across length scales is addressed with examples demonstrating these key mechanistic principles of morphogenesis. Overall, this review highlights that curved interfaces are not merely a passive by-product of the chemical, biological, and mechanical processes but that curvature acts also as a signal that co-determines these processes.
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Affiliation(s)
- Barbara Schamberger
- Department of the Chemistry and Physics of Materials, Paris-Lodron University of Salzburg, 5020, Salzburg, Austria
| | - Ricardo Ziege
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14476, Potsdam, Germany
| | - Karine Anselme
- IS2M (CNRS - UMR 7361), Université de Haute-Alsace, F-68100, Mulhouse, France
- Université de Strasbourg, F-67081, Strasbourg, France
| | - Martine Ben Amar
- Department of Physics, Laboratoire de Physique de l'Ecole Normale Supérieure, 24 rue Lhomond, 75005, Paris, France
| | - Michał Bykowski
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, 02-096, Warsaw, Poland
| | - André P G Castro
- IDMEC, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal
- ESTS, Instituto Politécnico de Setúbal, 2914-761, Setúbal, Portugal
| | - Amaia Cipitria
- IS2M (CNRS - UMR 7361), Université de Haute-Alsace, F-68100, Mulhouse, France
- Group of Bioengineering in Regeneration and Cancer, Biodonostia Health Research Institute, 20014, San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Rhoslyn A Coles
- Cluster of Excellence, Matters of Activity, Humboldt-Universität zu Berlin, 10178, Berlin, Germany
| | - Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, 14476, Potsdam, Germany
| | - Michaela Eder
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14476, Potsdam, Germany
| | - Sebastian Ehrig
- Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
- Berlin Institute for Medical Systems Biology, 10115, Berlin, Germany
| | - Luis M Escudero
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Biología Celular, Universidad de Sevilla, 41013, Seville, Spain
- Biomedical Network Research Centre on Neurodegenerative Diseases (CIBERNED), 28031, Madrid, Spain
| | - Myfanwy E Evans
- Institute for Mathematics, University of Potsdam, 14476, Potsdam, Germany
| | - Paulo R Fernandes
- IDMEC, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14476, Potsdam, Germany
| | - Liesbet Geris
- Biomechanics Research Unit, GIGA In Silico Medicine, University of Liège, 4000, Liège, Belgium
| | - Notburga Gierlinger
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (Boku), 1190, Vienna, Austria
| | - Edouard Hannezo
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical engineering, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia
| | - Jacob J K Kirkensgaard
- Condensed Matter Physics, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100, København Ø, Denmark
- Ingredients and Dairy Technology, Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958, Frederiksberg, Denmark
| | - Philip Kollmannsberger
- Center for Computational and Theoretical Biology, University of Würzburg, 97074, Würzburg, Germany
| | - Łucja Kowalewska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, 02-096, Warsaw, Poland
| | - Nicholas A Kurniawan
- Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Ioannis Papantoniou
- Prometheus Division of Skeletal Tissue Engineering, KU Leuven, O&N1, Herestraat 49, PB 813, 3000, Leuven, Belgium
- Skeletal Biology and Engineering Research Center, Department of Development and Regeneration, KU Leuven, O&N1, Herestraat 49, PB 813, 3000, Leuven, Belgium
- Institute of Chemical Engineering Sciences, Foundation for Research and Technology (FORTH), Stadiou Str., 26504, Patras, Greece
| | - Laurent Pieuchot
- IS2M (CNRS - UMR 7361), Université de Haute-Alsace, F-68100, Mulhouse, France
- Université de Strasbourg, F-67081, Strasbourg, France
| | - Tiago H V Pires
- IDMEC, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal
| | - Lars D Renner
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, 01069, Dresden, Germany
| | | | - Gerd E Schröder-Turk
- School of Physics, Chemistry and Mathematics, Murdoch University, 90 South St, Murdoch, WA, 6150, Australia
- Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT, 2600, Australia
| | - Anupam Sengupta
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, L-1511, Luxembourg City, Grand Duchy of Luxembourg
| | - Vikas R Sharma
- Department of the Chemistry and Physics of Materials, Paris-Lodron University of Salzburg, 5020, Salzburg, Austria
| | - Antonio Tagua
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Biología Celular, Universidad de Sevilla, 41013, Seville, Spain
- Biomedical Network Research Centre on Neurodegenerative Diseases (CIBERNED), 28031, Madrid, Spain
| | - Caterina Tomba
- Univ Lyon, CNRS, INSA Lyon, Ecole Centrale de Lyon, Université Claude Bernard Lyon 1, CPE Lyon, INL, UMR5270, 69622, Villeurbanne, France
| | - Xavier Trepat
- ICREA at the Institute for Bioengineering of Catalonia, The Barcelona Institute for Science and Technology, 08028, Barcelona, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 08028, Barcelona, Spain
| | - Sarah L Waters
- Mathematical Institute, University of Oxford, OX2 6GG, Oxford, UK
| | - Edwina F Yeo
- Mathematical Institute, University of Oxford, OX2 6GG, Oxford, UK
| | - Andreas Roschger
- Department of the Chemistry and Physics of Materials, Paris-Lodron University of Salzburg, 5020, Salzburg, Austria
| | - Cécile M Bidan
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14476, Potsdam, Germany
| | - John W C Dunlop
- Department of the Chemistry and Physics of Materials, Paris-Lodron University of Salzburg, 5020, Salzburg, Austria
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5
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Pedersen MC, Hyde ST, Ramsden S, Kirkensgaard JJK. Mapping hyperbolic order in curved materials. Soft Matter 2023; 19:1586-1595. [PMID: 36749349 DOI: 10.1039/d2sm01403c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Nature employs an impressive range of topologically complex ordered nanostructures that occur in various forms in both natural and synthetic materials. A particular class of these exhibits negative curvature and forms periodic saddle-shaped surfaces in three dimensions. Unlike pattern formation on flat or positively curved surfaces like spherical systems, the understanding of patterning on such surfaces is highly complicated due to the structures being intrinsically intertwined in three dimensions. We present a new method for visualisation and analysis of patterns on triply periodic negatively curved surfaces by mapping to two-dimensional hyperbolic space analogous to spherical projections in cartography thus effectively creating a more accessible "hyperbolic map" of the pattern. Specifically, we exemplify the method via the simplest triply periodic minimal surfaces: the Primitive, Diamond, and Gyroid in their universal cover along with decorations from a soft materials, whose structures involve decorations of soft matter on negatively curved surfaces, not necessarily minimal.
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Affiliation(s)
| | | | - Stuart Ramsden
- National Computational Infrastructure (NCI) Vizlab, Australian National University, Australia
| | - Jacob J K Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Denmark.
- Department of Food Science, University of Copenhagen, Denmark
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6
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Mathiesen JK, Quinson J, Blaseio S, Kjær ETS, Dworzak A, Cooper SR, Pedersen JK, Wang B, Bizzotto F, Schröder J, Kinnibrugh TL, Simonsen SB, Theil Kuhn L, Kirkensgaard JJK, Rossmeisl J, Oezaslan M, Arenz M, Jensen KMØ. Chemical Insights into the Formation of Colloidal Iridium Nanoparticles from In Situ X-ray Total Scattering: Influence of Precursors and Cations on the Reaction Pathway. J Am Chem Soc 2023; 145:1769-1782. [PMID: 36631996 DOI: 10.1021/jacs.2c10814] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Iridium nanoparticles are important catalysts for several chemical and energy conversion reactions. Studies of iridium nanoparticles have also been a key for the development of kinetic models of nanomaterial formation. However, compared to other metals such as gold or platinum, knowledge on the nature of prenucleation species and structural insights into the resultant nanoparticles are missing, especially for nanoparticles obtained from IrxCly precursors investigated here. We use in situ X-ray total scattering (TS) experiments with pair distribution function (PDF) analysis to study a simple, surfactant-free synthesis of colloidal iridium nanoparticles. The reaction is performed in methanol at 50 °C with only a base and an iridium salt as precursor. From different precursor salts─IrCl3, IrCl4, H2IrCl6, or Na2IrCl6─colloidal nanoparticles as small as Ir∼55 are obtained as the final product. The nanoparticles do not show the bulk iridium face-centered cubic (fcc) structure but show decahedral and icosahedral structures. The formation route is highly dependent on the precursor salt used. Using IrCl3 or IrCl4, metallic iridium nanoparticles form rapidly from IrxClyn- complexes, whereas using H2IrCl6 or Na2IrCl6, the iridium nanoparticle formation follows a sudden growth after an induction period and the brief appearance of a crystalline phase. With H2IrCl6, the formation of different Irn (n = 55, 55, 85, and 116) nanoparticles depends on the nature of the cation in the base (LiOH, NaOH, KOH, or CsOH, respectively) and larger particles are obtained with larger cations. As the particles grow, the nanoparticle structure changes from partly icosahedral to decahedral. The results show that the synthesis of iridium nanoparticles from IrxCly is a valuable iridium nanoparticle model system, which can provide new compositional and structural insights into iridium nanoparticle formation and growth.
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Affiliation(s)
- Jette K Mathiesen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark.,Department of Physics, Technical University of Denmark, Fysikvej Bldg. 312, 2800Kgs. Lyngby, Denmark
| | - Jonathan Quinson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark.,Department of Biochemical and Chemical Engineering, Aarhus University, Åbogade 40, 8200Aarhus N, Denmark
| | - Sonja Blaseio
- Institute of Technical Chemistry, Technische Universität Braunschweig, Franz-Liszt Str. 35a, 38106Braunschweig, Germany
| | - Emil T S Kjær
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark
| | - Alexandra Dworzak
- Institute of Technical Chemistry, Technische Universität Braunschweig, Franz-Liszt Str. 35a, 38106Braunschweig, Germany
| | - Susan R Cooper
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark
| | - Jack K Pedersen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark
| | - Baiyu Wang
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark
| | - Francesco Bizzotto
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012Bern, Switzerland
| | - Johanna Schröder
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012Bern, Switzerland
| | - Tiffany L Kinnibrugh
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois60439, United States
| | - Søren B Simonsen
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej Bldg. 310, 2800Kgs. Lyngby, Denmark
| | - Luise Theil Kuhn
- Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej Bldg. 310, 2800Kgs. Lyngby, Denmark
| | - Jacob J K Kirkensgaard
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958Frederiksberg C, Denmark.,Niels-Bohr-Institute, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark
| | - Jan Rossmeisl
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark
| | - Mehtap Oezaslan
- Institute of Technical Chemistry, Technische Universität Braunschweig, Franz-Liszt Str. 35a, 38106Braunschweig, Germany
| | - Matthias Arenz
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012Bern, Switzerland
| | - Kirsten M Ø Jensen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100Copenhagen Ø, Denmark
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7
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Du J, Quinson J, Zhang D, Wang B, Wiberg GKH, Pittkowski RK, Schröder J, Simonsen SB, Kirkensgaard JJK, Li Y, Reichenberger S, Barcikowski S, Jensen KMØ, Arenz M. Nanocomposite Concept for Electrochemical In Situ Preparation of Pt-Au Alloy Nanoparticles for Formic Acid Oxidation. JACS Au 2022; 2:1757-1768. [PMID: 35911453 PMCID: PMC9327087 DOI: 10.1021/jacsau.2c00335] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Herein, we report a straightforward approach for the in situ preparation of Pt-Au alloy nanoparticles from Pt + xAu/C nanocomposites using monometallic colloidal nanoparticles as starting blocks. Four different compositions with fixed Pt content and varying Pt to Au mass ratios from 1:1 up to 1:7 were prepared as formic acid oxidation reaction (FAOR) catalysts. The study was carried out in a gas diffusion electrode (GDE) setup. It is shown that the presence of Au in the nanocomposites substantially improves the FAOR activity with respect to pure Pt/C, which serves as a reference. The nanocomposite with a mass ratio of 1:5 between Pt and Au displays the best performance during potentiodynamic tests, with the electro-oxidation rates, overpotential, and poisoning resistance being improved simultaneously. By comparison, too low or too high Au contributions in the nanocomposites lead to an unbalanced performance in the FAOR. The combination of operando small-angle X-ray scattering (SAXS), scanning transmission electron microscopy (STEM) elemental mapping, and wide-angle X-ray scattering (WAXS) reveals that for the nanocomposite with a 1:5 mass ratio, a conversion between Pt and Au from separate nanoparticles to alloy nanoparticles occurs during continuous potential cycling in formic acid. By comparison, the nanocomposites with lower Au contents, for example, 1:2, exhibit less in situ alloying, and the concomitant performance improvement is less pronounced. On applying identical location transmission electron microscopy (IL-TEM), it is revealed that the in situ alloying is due to Pt dissolution and re-deposition onto Au as well as Pt migration and coalescence with Au nanoparticles.
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Affiliation(s)
- Jia Du
- Department of Chemistry,
Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Jonathan Quinson
- Department of Chemistry, University of
Copenhagen, 2100 Copenhagen, Denmark
- Department of Biochemical and Chemical Engineering, University of Aarhus, 8200 Aarhus, Denmark
| | - Damin Zhang
- Department of Chemistry,
Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Baiyu Wang
- Department of Chemistry, University of
Copenhagen, 2100 Copenhagen, Denmark
| | - Gustav K. H. Wiberg
- Department of Chemistry,
Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | | | - Johanna Schröder
- Department of Chemistry,
Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Søren B. Simonsen
- Department of Energy
Conversion and Storage, Technical University
of Denmark, 2800 Lyngby, Denmark
| | - Jacob J. K. Kirkensgaard
- Department of Food
Science, University of Copenhagen, 1958 Frederiksberg, Denmark
- Niels-Bohr-Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Yao Li
- Technical Chemistry I and Center of Nanointegration Duisburg Essen
(CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
| | - Sven Reichenberger
- Technical Chemistry I and Center of Nanointegration Duisburg Essen
(CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
| | - Stephan Barcikowski
- Technical Chemistry I and Center of Nanointegration Duisburg Essen
(CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
| | | | - Matthias Arenz
- Department of Chemistry,
Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
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8
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Schröder J, Pittkowski RK, Martens I, Chattot R, Drnec J, Quinson J, Kirkensgaard JJK, Arenz M. Tracking the Catalyst Layer Depth-Dependent Electrochemical Degradation of a Bimodal Pt/C Fuel Cell Catalyst: A Combined Operando Small- and Wide-Angle X-ray Scattering Study. ACS Catal 2022. [DOI: 10.1021/acscatal.1c04365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Johanna Schröder
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Rebecca K. Pittkowski
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Isaac Martens
- European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Raphaël Chattot
- European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Jakub Drnec
- European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Jonathan Quinson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Jacob J. K. Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Denmark
| | - Matthias Arenz
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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9
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Mortensen K, Borger AL, Kirkensgaard JJK, Huang Q, Hassager O, Almdal K. Small-Angle Neutron Scattering Study of the Structural Relaxation of Elongationally Oriented, Moderately Stretched Three-Arm Star Polymers. Phys Rev Lett 2021; 127:177801. [PMID: 34739279 DOI: 10.1103/physrevlett.127.177801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
We present structural relaxation studies of a polystyrene star polymer after cessation of high-rate extensional flow. During the steady-state flow, the scattering pattern shows two sets of independent correlations peaks, reflecting the structure of a polymer confined in a fully oriented three-armed tube. Upon cessation of flow, the relaxation constitutes three distinct regimes. In a first regime, the perpendicular correlation peaks disappear, signifying disruption of the virtual tube. In a second regime, broad scattering arcs emerge, reflecting relaxation from highly aligned chains to more relaxed, still anisotropic form. New entanglements dominate the last relaxation regime where the scattering pattern evolves to a successively elliptical and circular pattern, reflecting relaxation via reptation.
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Affiliation(s)
- Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Anine L Borger
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jacob J K Kirkensgaard
- Niels Bohr Institute and Dept. Food Science, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Qian Huang
- Polymer Research Institute, Sichuan University, 610065 Chengdu, China
| | - Ole Hassager
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Kristoffer Almdal
- Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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10
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Yang S, Tyler AII, Ahrné L, Kirkensgaard JJK. Skimmed milk structural dynamics during high hydrostatic pressure processing from in situ SAXS. Food Res Int 2021; 147:110527. [PMID: 34399505 DOI: 10.1016/j.foodres.2021.110527] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 05/27/2021] [Accepted: 06/11/2021] [Indexed: 10/21/2022]
Abstract
Understanding the changes in milk at a nanostructural level during high-pressure (HP) treatment can provide new insights to improve the safety and functionality of dairy products. In this study, modifications of milk nanostructure during HP were studied in situ by small-angle X-ray scattering (SAXS). Skimmed milk was pressurized to 200 or 400 MPa at 25, 40 or 60 °C and held for 5 or 10 min, and the effect of single- and double-HP treatment was also investigated. In most cases, the SAXS patterns of skimmed milk are well fitted with a three-population model: a low-q micellar feature reflecting the overall micelle size (~0.002 Å-1), a small casein cluster contribution at intermediate-q (around 0.01 Å-1) and a high-q (0.08-0.1 Å-1) population of milk protein inhomogeneities. However, at 60 °C a scattering feature of colloidal calcium phosphate (CCP) which is normally only seen with neutron scattering, was observed at 0.035 Å-1. By varying the pressure, temperature, holding and depressurization times, as well as performing cycled pressure treatment, we followed the dynamic structural changes in the skimmed milk protein structure at different length scales, which depending on the processing conditions, were irreversible or reversible within the timescales investigated. Pressure and temperature of the HP process have major effects, not only on size of casein micelles, but also on "protein inhomogeneities" within their internal structure. Under HP, increasing processing time at 200 MPa induced re-association of the micelles, however, the changes in the internal structure were more pressure-dependent than time dependent.
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Affiliation(s)
- Shuailing Yang
- Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark
| | - Arwen I I Tyler
- School of Food Science and Nutrition, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Lilia Ahrné
- Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark.
| | - Jacob J K Kirkensgaard
- Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark; Niels Bohr Institute, University of Copenhagen, DK-2100 København Ø, Denmark.
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11
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Pedersen MC, Kirkensgaard JJK, Hyde ST. Behind the curve: generating and analysing nets and tessellations on periodic minimal surfaces in their universal covering space. Acta Crystallogr A Found Adv 2021. [DOI: 10.1107/s0108767321094241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Jakubauskas D, Mortensen K, Jensen PE, Kirkensgaard JJK. Small-Angle X-Ray and Neutron Scattering on Photosynthetic Membranes. Front Chem 2021; 9:631370. [PMID: 33954157 PMCID: PMC8090863 DOI: 10.3389/fchem.2021.631370] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/01/2021] [Indexed: 11/26/2022] Open
Abstract
Ultrastructural membrane arrangements in living cells and their dynamic remodeling in response to environmental changes remain an area of active research but are also subject to large uncertainty. The use of noninvasive methods such as X-ray and neutron scattering provides an attractive complimentary source of information to direct imaging because in vivo systems can be probed in near-natural conditions. However, without solid underlying structural modeling to properly interpret the indirect information extracted, scattering provides at best qualitative information and at worst direct misinterpretations. Here we review the current state of small-angle scattering applied to photosynthetic membrane systems with particular focus on data interpretation and modeling.
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Affiliation(s)
- Dainius Jakubauskas
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Kell Mortensen
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Poul Erik Jensen
- Department of Food Science, University of Copenhagen, Copenhagen, Denmark
| | - Jacob J. K. Kirkensgaard
- X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Food Science, University of Copenhagen, Copenhagen, Denmark
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13
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Mathiesen JK, Quinson J, Dworzak A, Vosch T, Juelsholt M, Kjær ETS, Schröder J, Kirkensgaard JJK, Oezaslan M, Arenz M, Jensen KMØ. Insights from In Situ Studies on the Early Stages of Platinum Nanoparticle Formation. J Phys Chem Lett 2021; 12:3224-3231. [PMID: 33764071 DOI: 10.1021/acs.jpclett.1c00241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Understanding the formation of nanomaterials down to the atomic level is key to rational design of advanced materials. Despite their widespread use and intensive study over the years, the detailed formation mechanism of platinum (Pt) nanoparticles remains challenging to explore and rationalize. Here, various in situ characterization techniques, and in particular X-ray total scattering with pair distribution function (PDF) analysis, are used to follow the structural and chemical changes taking place during a surfactant-free synthesis of Pt nanoparticles in alkaline methanol. Polynuclear structures form at the beginning of the synthesis, and Pt-Pt pair distances are identified before any nanoparticles are generated. The structural motifs best describing the species formed change with time, e.g., from [PtCl5-PtCl5] and [PtCl6-Pt2Cl6-PtCl6] to [Pt2Cl10-Pt3Cl8-Pt2Cl10]. The formation of these polynuclear structures with Pt-Pt coordination before the formation of the nanoparticles is suggested to account for the fast nucleation observed in the synthesis.
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Affiliation(s)
- Jette K Mathiesen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Jonathan Quinson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Alexandra Dworzak
- School of Mathematics and Science, Department of Chemistry, Carl von Ossietzky University of Oldenburg, 26111 Oldenburg, Germany
- Technical Electrocatalysis Laboratory, Institute of Technical Chemistry, Technical University of Braunschweig, Franz-Liszt Strasse 35a, 38106 Braunschweig, Germany
| | - Tom Vosch
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Mikkel Juelsholt
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Emil T S Kjær
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Johanna Schröder
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3 CH-3012 Bern, Switzerland
| | - Jacob J K Kirkensgaard
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark
| | - Mehtap Oezaslan
- School of Mathematics and Science, Department of Chemistry, Carl von Ossietzky University of Oldenburg, 26111 Oldenburg, Germany
- Technical Electrocatalysis Laboratory, Institute of Technical Chemistry, Technical University of Braunschweig, Franz-Liszt Strasse 35a, 38106 Braunschweig, Germany
| | - Matthias Arenz
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3 CH-3012 Bern, Switzerland
| | - Kirsten M Ø Jensen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
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14
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Sievers GW, Jensen AW, Quinson J, Zana A, Bizzotto F, Oezaslan M, Dworzak A, Kirkensgaard JJK, Smitshuysen TEL, Kadkhodazadeh S, Juelsholt M, Jensen KMØ, Anklam K, Wan H, Schäfer J, Čépe K, Escudero-Escribano M, Rossmeisl J, Quade A, Brüser V, Arenz M. Self-supported Pt-CoO networks combining high specific activity with high surface area for oxygen reduction. Nat Mater 2021; 20:208-213. [PMID: 32839587 DOI: 10.1038/s41563-020-0775-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/15/2020] [Indexed: 05/23/2023]
Abstract
Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum-cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum-cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification.
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Affiliation(s)
- Gustav W Sievers
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany.
| | - Anders W Jensen
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Jonathan Quinson
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Alessandro Zana
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Francesco Bizzotto
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Mehtap Oezaslan
- Department of Chemistry, School of Mathematics and Science, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
- Technical Electrocatalysis Laboratory, Institute of Technical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Alexandra Dworzak
- Department of Chemistry, School of Mathematics and Science, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
- Technical Electrocatalysis Laboratory, Institute of Technical Chemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Jacob J K Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Food Science, University of Copenhagen, Frederiksberg, Denmark
| | | | | | - Mikkel Juelsholt
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | | | - Kirsten Anklam
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Hao Wan
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Jan Schäfer
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Klára Čépe
- Regional Centre of Advanced Technologies and Materials, Olomouc, Czech Republic
| | | | - Jan Rossmeisl
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Antje Quade
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Volker Brüser
- Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Matthias Arenz
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland.
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15
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Alinejad S, Quinson J, Schröder J, Kirkensgaard JJK, Arenz M. Carbon-Supported Platinum Electrocatalysts Probed in a Gas Diffusion Setup with Alkaline Environment: How Particle Size and Mesoscopic Environment Influence the Degradation Mechanism. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03184] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shima Alinejad
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Jonathan Quinson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Johanna Schröder
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Jacob J. K. Kirkensgaard
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Denmark
| | - Matthias Arenz
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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16
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Cramer Pedersen M, Robins V, Mortensen K, Kirkensgaard JJK. Evolution of local motifs and topological proximity in self-assembled quasi-crystalline phases. Proc Math Phys Eng Sci 2020; 476:20200170. [PMID: 33071571 PMCID: PMC7544332 DOI: 10.1098/rspa.2020.0170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 08/04/2020] [Indexed: 12/30/2023] Open
Abstract
Using methods from the field of topological data analysis, we investigate the self-assembly and emergence of three-dimensional quasi-crystalline structures in a single-component colloidal system. Combining molecular dynamics and persistent homology, we analyse the time evolution of persistence diagrams and particular local structural motifs. Our analysis reveals the formation and dissipation of specific particle constellations in these trajectories, and shows that the persistence diagrams are sensitive to nucleation and convergence to a final structure. Identification of local motifs allows quantification of the similarities between the final structures in a topological sense. This analysis reveals a continuous variation with density between crystalline clathrate, quasi-crystalline, and disordered phases quantified by 'topological proximity', a visualization of the Wasserstein distances between persistence diagrams. From a topological perspective, there is a subtle, but direct connection between quasi-crystalline, crystalline and disordered states. Our results demonstrate that topological data analysis provides detailed insights into molecular self-assembly.
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Affiliation(s)
| | - Vanessa Robins
- Department of Applied Mathematics, Australian National University, Canberra, Australia
| | - Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Jacob J. K. Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- Department of Food Science, University of Copenhagen, Copenhagen, Denmark
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17
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Quinson J, Neumann S, Kacenauskaite L, Bucher J, Kirkensgaard JJK, Simonsen SB, Theil Kuhn L, Zana A, Vosch T, Oezaslan M, Kunz S, Arenz M. Solvent-Dependent Growth and Stabilization Mechanisms of Surfactant-Free Colloidal Pt Nanoparticles. Chemistry 2020; 26:9012-9023. [PMID: 32428349 DOI: 10.1002/chem.202001553] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/05/2020] [Indexed: 01/06/2023]
Abstract
Understanding the formation of nanoparticles (NPs) is key to develop materials by sustainable routes. The Co4CatTM process is a new synthesis of precious metal NPs in alkaline mono-alcohols well-suited to develop active nanocatalysts. The synthesis is 'facile', surfactant-free and performed under mild conditions like low temperature. The reducing properties of the solvent are here shown to strongly influence the formation of Pt NPs. Based on the in situ formation of CO adsorbed on the NP surface by solvent oxidation, a model is proposed that accounts for the different growth and stabilization mechanisms as well as re-dispersion properties of the surfactant-free NPs in different solvents. Using in situ and ex situ characterizations, it is established that in methanol, a slow nucleation with a limited NP growth is achieved. In ethanol, a fast nucleation followed by continuous and pronounced particle sintering occurs.
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Affiliation(s)
- Jonathan Quinson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| | - Sarah Neumann
- Institute for Applied and Physical Chemistry, University of Bremen, Leobenerstraße, 28359, Bremen, Germany
| | - Laura Kacenauskaite
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| | - Jan Bucher
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Jacob J K Kirkensgaard
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958, Frederiksberg C, Denmark
| | - Søren B Simonsen
- Imaging and Structural Analysis, Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej Bldg. 310, 2800 Kgs., Lyngby, Denmark
| | - Luise Theil Kuhn
- Imaging and Structural Analysis, Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej Bldg. 310, 2800 Kgs., Lyngby, Denmark
| | - Alessandro Zana
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Tom Vosch
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| | - Mehtap Oezaslan
- Department of Chemistry, School of Mathematics and Science, Carl von Ossietzky University of Oldenburg, 26111, Oldenburg, Germany.,Institute of Technical Chemistry, Technical University of Braunschweig, 38106, Braunschweig, Germany
| | - Sebastian Kunz
- Institute for Applied and Physical Chemistry, University of Bremen, Leobenerstraße, 28359, Bremen, Germany.,Central Department Research, Development, Technological Services (CRDS), Südzucker AG, Wormser Straße 11, 67283, Obrigheim, Germany
| | - Matthias Arenz
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland
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18
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Quinson J, Inaba M, Neumann S, Swane AA, Bucher J, Simonsen SB, Theil Kuhn L, Kirkensgaard JJK, Jensen KMØ, Oezaslan M, Kunz S, Arenz M. Correction to “Investigating Particle Size Effects in Catalysis by Applying a Size-Controlled and Surfactant-Free Synthesis of Colloidal Nanoparticles in Alkaline Ethylene Glycol: Case Study of the Oxygen Reduction Reaction on Pt”. ACS Catal 2020. [DOI: 10.1021/acscatal.0c00452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Arminio‐Ravelo JA, Quinson J, Pedersen MA, Kirkensgaard JJK, Arenz M, Escudero‐Escribano M. Synthesis of Iridium Nanocatalysts for Water Oxidation in Acid: Effect of the Surfactant. ChemCatChem 2020. [DOI: 10.1002/cctc.201902190] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
| | - Jonathan Quinson
- Department of ChemistryUniversity of Copenhagen Universitetsparken 5 Copenhagen DK-2100 Denmark
| | - Mads A. Pedersen
- Niels Bohr InstituteUniversity of Copenhagen Universitetsparken 5 Copenhagen DK-2100 Denmark
| | - Jacob J. K. Kirkensgaard
- Niels Bohr InstituteUniversity of Copenhagen Universitetsparken 5 Copenhagen DK-2100 Denmark
- Department of Food ScienceUniversity of Copenhagen Rolighedsvej 26 Frederiksberg 1958 Denmark
| | - Matthias Arenz
- Department of Chemistry and BiochemistryUniversity of Bern Freiestrasse 3 Bern CH-3012 Switzerland
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20
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Hain TM, Schröder-Turk GE, Kirkensgaard JJK. Patchy particles by self-assembly of star copolymers on a spherical substrate: Thomson solutions in a geometric problem with a color constraint. Soft Matter 2019; 15:9394-9404. [PMID: 31595280 DOI: 10.1039/c9sm01460h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Confinement or geometric frustration is known to alter the structure of soft matter, including copolymeric melts, and can consequently be used to tune structure and properties. Here we investigate the self-assembly of ABC and ABB 3-miktoarm star copolymers confined to a spherical shell using coarse-grained dissipative particle dynamics simulations. In bulk and flat geometries the ABC stars form hexagonal tilings, but this is topologically prohibited in a spherical geometry which normally is alleviated by forming pentagonal tiles. However, the molecular architecture of the ABC stars implies an additional 'color constraint' which only allows even tilings (where all polygons have an even number of edges) and we study the effect of these simultaneous constraints. We find that both ABC and ABB systems form spherical tiling patterns, the type of which depends on the radius of the spherical substrate. For small spherical substrates, all solutions correspond to patterns solving the Thomson problem of placing mobile repulsive electric charges on a sphere. In ABC systems we find three coexisting, possibly different tilings, one in each color, each of them solving the Thomson problem simultaneously. For all except the smallest substrates, we find competing solutions with seemingly degenerate free energies that occur with different probabilities. Statistically, an observer who is blind to the differences between B and C can tell from the structure of the A domains if the system is an ABC or an ABB star copolymer system.
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Affiliation(s)
- Tobias M Hain
- College of Science, Health, Engineering and Education, Mathematics and Statistics, Murdoch University, 90 South Street, 6150 Murdoch, Western Australia, Australia.
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21
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Bizzotto F, Quinson J, Zana A, Kirkensgaard JJK, Dworzak A, Oezaslan M, Arenz M. Ir nanoparticles with ultrahigh dispersion as oxygen evolution reaction (OER) catalysts: synthesis and activity benchmarking. Catal Sci Technol 2019. [DOI: 10.1039/c9cy01728c] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we present a facile and straightforward approach to synthesize, activate and benchmark small, i.e. 1.6 nm in diameter, Ir nanoparticles (NP) as oxygen evolution reaction (OER) catalysts.
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Affiliation(s)
- Francesco Bizzotto
- Department of Chemistry and Biochemistry
- University of Bern
- CH-3012 Bern
- Switzerland
| | - Jonathan Quinson
- Chemistry Department
- University of Copenhagen
- 2100 Copenhagen Ø
- Denmark
| | - Alessandro Zana
- Department of Chemistry and Biochemistry
- University of Bern
- CH-3012 Bern
- Switzerland
| | | | - Alexandra Dworzak
- School of Mathematics and Science
- Department of Chemistry
- Carl von Ossietzky Universität
- 26111 Oldenburg
- Germany
| | - Mehtap Oezaslan
- School of Mathematics and Science
- Department of Chemistry
- Carl von Ossietzky Universität
- 26111 Oldenburg
- Germany
| | - Matthias Arenz
- Department of Chemistry and Biochemistry
- University of Bern
- CH-3012 Bern
- Switzerland
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22
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Quinson J, Inaba M, Neumann S, Swane AA, Bucher J, Simonsen SB, Theil Kuhn L, Kirkensgaard JJK, Jensen KMØ, Oezaslan M, Kunz S, Arenz M. Investigating Particle Size Effects in Catalysis by Applying a Size-Controlled and Surfactant-Free Synthesis of Colloidal Nanoparticles in Alkaline Ethylene Glycol: Case Study of the Oxygen Reduction Reaction on Pt. ACS Catal 2018. [DOI: 10.1021/acscatal.8b00694] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Jonathan Quinson
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Masanori Inaba
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Sarah Neumann
- Institute of Applied and Physical Chemistry, University of Bremen, Leobenerstraße, 28359 Bremen, Germany
| | - Andreas A. Swane
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - J. Bucher
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Søren B. Simonsen
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Luise Theil Kuhn
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Jacob J. K. Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Kirsten M. Ø. Jensen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Mehtap Oezaslan
- School of Mathematics and Science Department of Chemistry, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany
| | - Sebastian Kunz
- Institute of Applied and Physical Chemistry, University of Bremen, Leobenerstraße, 28359 Bremen, Germany
| | - Matthias Arenz
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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23
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Rose F, Roovers S, Fano M, Harloff-Helleberg S, Kirkensgaard JJK, Hejnaes K, Fischer P, Foged C. Temperature-Induced Self-Assembly of the Group B Streptococcus (GBS) Fusion Antigen GBS-NN. Mol Pharm 2018; 15:2584-2593. [PMID: 29745668 DOI: 10.1021/acs.molpharmaceut.8b00101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Group B Streptococcus (GBS) is a leading cause of serious bacterial neonatal infections worldwide, which provides an unmet medical need for a globally effective vaccine. The recombinant GBS fusion antigen GBS-NN contains the N-terminal regions of the GBS Rib and Alpha C proteins. It shows promising immunogenicity eliciting protective immunity in mice and encouraging results in early human clinical trials. Understanding the physical stability of GBS-NN containing conformational B-cell epitopes is crucial to ensure optimal vaccine stability, efficacy, and safety. We initially discovered that GBS-NN is prone to form higher-order structures at elevated temperatures. We therefore investigated the self-assembly behavior of GBS-NN and characterized the higher-order conformational structures as a function of temperature. In the native state, GBS-NN exists as a monomer and has a secondary structure containing α-helix and β-sheet. Langmuir studies demonstrated that the native protein is highly surface-active and forms a monolayer film at the air-water interface because of its amphipathic properties. The conformational stability of GBS-NN was measured as a function of temperature. GBS-NN has an unusual thermal behavior with a phase transition of approximately 61 °C, which is not accompanied by any major changes in the secondary structure. However, the antigen showed irreversible self-assembly as a function of temperature into higher-order structures with a hydrodynamic diameter of approximately 100 nm. Cryo-transmission electron microscopy analyses demonstrated that these self-assemblies consist of vesicular, ring-like structures with a hollow aqueous interior. Therefore, GBS-NN is a physically stable monomeric protein but is prone to temperature-induced self-assembly above 61 °C.
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Affiliation(s)
| | - Silke Roovers
- Laboratory of General Biochemistry and Physical Pharmacy , Ghent University , Ottergemsesteenweg 460 , 9000 Ghent , Belgium
| | | | | | - Jacob J K Kirkensgaard
- Niels Bohr Institute, Faculty of Science , University of Copenhagen , Universitetsparken 5 , DK-2100 Copenhagen Ø , Denmark
| | - Kim Hejnaes
- MinervaX ApS , Ole Maaløes Vej 3 , DK-2200 Copenhagen N , Denmark
| | - Per Fischer
- MinervaX ApS , Ole Maaløes Vej 3 , DK-2200 Copenhagen N , Denmark
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24
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Mortensen K, Borger AL, Kirkensgaard JJK, Garvey CJ, Almdal K, Dorokhin A, Huang Q, Hassager O. Structural Studies of Three-Arm Star Block Copolymers Exposed to Extreme Stretch Suggests a Persistent Polymer Tube. Phys Rev Lett 2018; 120:207801. [PMID: 29864321 DOI: 10.1103/physrevlett.120.207801] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/16/2018] [Indexed: 06/08/2023]
Abstract
We present structural small-angle neutron scattering studies of a three-armed polystyrene star polymer with short deuterated segments at the end of each arm. We show that the form factor of the three-armed star molecules in the relaxed state agrees with that of the random phase approximation of Gaussian chains. Upon exposure to large extensional flow conditions, the star polymers change conformation resulting in a highly stretched structure that mimics a fully extended three-armed tube model. All three arms are parallel to the flow, one arm being either in positive or negative stretching direction, while the two other arms are oriented parallel, right next to each other in the direction opposite to the first arm.
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Affiliation(s)
- Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Anine L Borger
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | | | - Christopher J Garvey
- Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Kristoffer Almdal
- Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Andriy Dorokhin
- Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Qian Huang
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Ole Hassager
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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25
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Sagnelli D, Hooshmand K, Kemmer GC, Kirkensgaard JJK, Mortensen K, Giosafatto CVL, Holse M, Hebelstrup KH, Bao J, Stelte W, Bjerre AB, Blennow A. Cross-Linked Amylose Bio-Plastic: A Transgenic-Based Compostable Plastic Alternative. Int J Mol Sci 2017; 18:ijms18102075. [PMID: 28973963 PMCID: PMC5666757 DOI: 10.3390/ijms18102075] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/20/2017] [Accepted: 09/25/2017] [Indexed: 12/28/2022] Open
Abstract
Bio-plastics and bio-materials are composed of natural or biomass derived polymers, offering solutions to solve immediate environmental issues. Polysaccharide-based bio-plastics represent important alternatives to conventional plastic because of their intrinsic biodegradable nature. Amylose-only (AO), an engineered barley starch with 99% amylose, was tested to produce cross-linked all-natural bioplastic using normal barley starch as a control. Glycerol was used as plasticizer and citrate cross-linking was used to improve the mechanical properties of cross-linked AO starch extrudates. Extrusion converted the control starch from A-type to Vh- and B-type crystals, showing a complete melting of the starch crystals in the raw starch granules. The cross-linked AO and control starch specimens displayed an additional wide-angle diffraction reflection. Phospholipids complexed with Vh-type single helices constituted an integrated part of the AO starch specimens. Gas permeability tests of selected starch-based prototypes demonstrated properties comparable to that of commercial Mater-Bi© plastic. The cross-linked AO prototypes had composting characteristics not different from the control, indicating that the modified starch behaves the same as normal starch. The data shows the feasibility of producing all-natural bioplastic using designer starch as raw material.
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Affiliation(s)
- Domenico Sagnelli
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg, Denmark.
| | - Kourosh Hooshmand
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg, Denmark.
| | - Gerdi Christine Kemmer
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg, Denmark.
| | | | - Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
| | | | - Mette Holse
- Department of Food Science, University of Copenhagen, 1958 Frederiksberg, Denmark.
| | - Kim H Hebelstrup
- Department of Molecular Biology and Genetics, Aarhus University, 4200 Slagelse, Denmark.
| | - Jinsong Bao
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China.
| | - Wolfgang Stelte
- Center for Bioresources and Biorefinery, Danish Technological Institute, Gregersenvej 7, 2630 Taatsrup, Denmark.
| | - Anne-Belinda Bjerre
- Center for Bioresources and Biorefinery, Danish Technological Institute, Gregersenvej 7, 2630 Taatsrup, Denmark.
| | - Andreas Blennow
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg, Denmark.
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26
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Sagnelli D, Kirkensgaard JJK, Giosafatto CVL, Ogrodowicz N, Kruczała K, Mikkelsen MS, Maigret JE, Lourdin D, Mortensen K, Blennow A. All-natural bio-plastics using starch-betaglucan composites. Carbohydr Polym 2017; 172:237-245. [PMID: 28606531 DOI: 10.1016/j.carbpol.2017.05.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/15/2017] [Accepted: 05/15/2017] [Indexed: 11/16/2022]
Abstract
Grain polysaccharides represent potential valuable raw materials for next-generation advanced and environmentally friendly plastics. Thermoplastic starch (TPS) is processed using conventional plastic technology, such as casting, extrusion, and molding. However, to adapt the starch to specific functionalities chemical modifications or blending with synthetic polymers, such as polycaprolactone are required (e.g. Mater-Bi). As an alternative, all-natural and compostable bio-plastics can be produced by blending starch with other polysaccharides. In this study, we used a maize starch (ST) and an oat β-glucan (BG) composite system to produce bio-plastic prototype films. To optimize performing conditions, we investigated the full range of ST:BG ratios for the casting (100:0, 75:25, 50:50, 25:75 and 0:100 BG). The plasticizer used was glycerol. Electron Paramagnetic Resonance (EPR), using TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) as a spin probe, showed that the composite films with high BG content had a flexible chemical environment. They showed decreased brittleness and improved cohesiveness with high stress and strain values at the break. Wide-angle X-ray diffraction displayed a decrease in crystallinity at high BG content. Our data show that the blending of starch with other natural polysaccharides is a noteworthy path to improve the functionality of all-natural polysaccharide bio-plastics systems.
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Affiliation(s)
- Domenico Sagnelli
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark.
| | | | | | - Natalia Ogrodowicz
- Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences, Kraków, Poland
| | | | - Mette S Mikkelsen
- Department of Food Science, University of Copenhagen, Frederiksberg C, Denmark
| | | | - Denis Lourdin
- Institut National De La Recherche Agronomique, Nantes, France
| | - Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Blennow
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark.
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Sagnelli D, Hebelstrup KH, Leroy E, Rolland-Sabaté A, Guilois S, Kirkensgaard JJK, Mortensen K, Lourdin D, Blennow A. Corrigendum to "Plant-crafted starches for bioplastics production" [Carbohydr. Polym. 152 (2016) 398-408]. Carbohydr Polym 2017; 157:903. [PMID: 27988005 DOI: 10.1016/j.carbpol.2016.10.077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Domenico Sagnelli
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Kim H Hebelstrup
- Department of Molecular Biology and Genetics, University of Aarhus, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Eric Leroy
- UR1268 Biopolymères Interactions Assemblages, INRA, F-44316 Nantes, France
| | | | - Sophie Guilois
- UR1268 Biopolymères Interactions Assemblages, INRA, F-44316 Nantes, France
| | - Jacob J K Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Denis Lourdin
- UR1268 Biopolymères Interactions Assemblages, INRA, F-44316 Nantes, France
| | - Andreas Blennow
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
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28
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Martin-Bertelsen B, Yaghmur A, Franzyk H, Justesen S, Kirkensgaard JJK, Foged C. Conserved Molecular Superlattices in a Series of Homologous Synthetic Mycobacterial Cell-Wall Lipids Forming Interdigitated Bilayers. Langmuir 2016; 32:12693-12701. [PMID: 27934510 DOI: 10.1021/acs.langmuir.6b01720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Synthetic analogues of the cell-wall lipid monomycoloyl glycerol (MMG) are promising as next-generation vaccine adjuvants. In the present study, the thermotropic phase behavior of an array of synthetic MMG analogues was examined by using simultaneous small- and wide-angle X-ray scattering under excess water conditions. The MMG analogues differed in the alkyl chain lengths and in the stereochemistry of the polar glycerol headgroup or of the lipid tails (native-like versus alternative compounds). All MMG analogues formed poorly hydrated lamellar phases at low temperatures and inverse hexagonal (H2) phases at higher temperatures prior to melting. MMG analogues with a native-like lipid acid configuration self-assembled into noninterdigitated bilayers whereas the analogues displaying an alternative lipid acid configuration formed interdigitated bilayers in a subgel (Lc') state. This is in contrast to previously described interdigitated phases for other lipids, which are usually in a gel (Lβ) state. All investigated MMG analogues displayed an abrupt direct temperature-induced phase transition from Lc' to H2. This transition is ultimately driven by the lipid chain melting and the accompanying change in molecular shape. No intermediate structures were found, but the entire array of MMG analogues displayed phase coexistence during the lamellar to H2 transition. The structural data also showed that the headgroups of the MMG analogues adopting the alternative lipid acid configuration were ordered and formed a two-dimensional molecular superlattice, which was conserved regardless of the lipid tail length. To our knowledge, the MMG analogues with an alternative lipid acid configuration represent the first example of a lipid system showing both interdigitation and superlattice formation, and as such could serve as an interesting model system for future studies. The MMG analogues are also relevant from a subunit vaccine perspective because they are well-tolerated and display promising immunopotentiating activity. The structural characterization described here will serve as a prerequisite for the rational design of nanoparticulate adjuvants with specific and tailored structural features.
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Affiliation(s)
| | | | | | | | - Jacob J K Kirkensgaard
- Niels Bohr Institute, Faculty of Science, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen, Denmark
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29
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Kirkensgaard JJK, Hengeller L, Dorokhin A, Huang Q, Garvey CJ, Almdal K, Hassager O, Mortensen K. Nematic effects and strain coupling in entangled polymer melts under strong flow. Phys Rev E 2016; 94:020502. [PMID: 27627228 DOI: 10.1103/physreve.94.020502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Indexed: 11/07/2022]
Abstract
We use small-angle neutron scattering (SANS) to study labeled short chains with and without the influence of an entangled and highly stretched surrounding environment of longer chains. We find unequivocal evidence of nematic effects as the blend chains in steady state flow are stretched a factor ∼1.5 more from the presence of the long chain nematic field. In the pure melt we confirm that the nonaffine mean-field result ν=0.5 for the strain coupling is still valid for very fast flows, while in the nematic system our analysis predicts an increased coupling constant. We provide a structural explanation for the two first regimes of the nonlinear relaxation, particularly a transition regime where the long chains are relaxing in a sea of reptating short chains.
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Affiliation(s)
- Jacob J K Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Ludovica Hengeller
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Andriy Dorokhin
- Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Qian Huang
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Christopher J Garvey
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - Kristoffer Almdal
- Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Ole Hassager
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Kell Mortensen
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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30
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Larsen AN, Sørensen KK, Johansen NT, Martel A, Kirkensgaard JJK, Jensen KJ, Arleth L, Midtgaard SR. Dimeric peptides with three different linkers self-assemble with phospholipids to form peptide nanodiscs that stabilize membrane proteins. Soft Matter 2016; 12:5937-5949. [PMID: 27306692 DOI: 10.1039/c6sm00495d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Three dimers of the amphipathic α-helical peptide 18A have been synthesized with different interhelical linkers inserted between the two copies of 18A. The dimeric peptides were denoted 'beltides' where Beltide-1 refers to the 18A-dimer without a linker, Beltide-2 is the 18A-dimer with proline (Pro) as a linker and Beltide-3 is the 18A-dimer linked by two glycines (Gly-Gly). The self-assembly of the beltides with the phospholipid DMPC was studied with and without the incorporated membrane protein bacteriorhodopsin (bR) through a combination of coarse-grained MD simulations, size-exclusion chromatography (SEC), circular dichroism (CD) spectroscopy, small-angle scattering (SAS), static light scattering (SLS) and UV-Vis spectroscopy. For all three beltides, MD and combined small-angle X-ray and -neutron scattering were consistent with a disc structure composed by a phospholipid bilayer surrounded by a belt of peptides and with a total disc diameter of approximately 10 nm. CD confirmed that all three beltides were α-helical in the free form and with DMPC. However, as shown by SEC the different interhelical linkers clearly led to different properties of the beltides. Beltide-3, with the Gly-Gly linker, was very adaptable such that peptide nanodiscs could be formed for a broad range of different peptide to lipid stoichiometries and therefore also possible disc-sizes. On the other hand, both Beltide-2 with the Pro linker and Beltide-1 without a linker were less adaptable and would only form discs of certain peptide to lipid stoichiometries. SLS revealed that the structural stability of the formed peptide nanodiscs was also highly affected by the linkers and it was found that Beltide-1 gave more stable discs than the other two beltides. With respect to membrane protein stabilization, each of the three beltides in combination with DMPC stabilizes the seven-helix transmembrane protein bacteriorhodopsin significantly better than the detergent octyl glucoside, but no significant difference was observed between the three beltides. We conclude that adaptability, size, and structural stability can be tuned by changing the interhelical linker while maintaining the properties of the discs with respect to membrane protein stabilization.
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Affiliation(s)
| | | | | | | | | | - Knud J Jensen
- Department of Chemistry, University of Copenhagen, Denmark
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Denmark.
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31
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Spanos I, Dideriksen K, Kirkensgaard JJK, Jelavic S, Arenz M. Structural disordering of de-alloyed Pt bimetallic nanocatalysts: the effect on oxygen reduction reaction activity and stability. Phys Chem Chem Phys 2015; 17:28044-53. [DOI: 10.1039/c4cp04264f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We show how alloying and excessive de-alloying affect ORR activity and the structural integrity of PEMFC nanocatalysts.
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Affiliation(s)
- Ioannis Spanos
- Nano-science Center
- Department of Chemistry
- University of Copenhagen
- DK-2100 Copenhagen Ø
- Denmark
| | - Knud Dideriksen
- Nano-science Center
- Department of Chemistry
- University of Copenhagen
- DK-2100 Copenhagen Ø
- Denmark
| | | | - Stanislav Jelavic
- Nano-science Center
- Department of Chemistry
- University of Copenhagen
- DK-2100 Copenhagen Ø
- Denmark
| | - Matthias Arenz
- Nano-science Center
- Department of Chemistry
- University of Copenhagen
- DK-2100 Copenhagen Ø
- Denmark
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32
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Fischer MG, de Campo L, Kirkensgaard JJK, Hyde ST, Schröder-Turk GE. The Tricontinuous 3ths(5) Phase: A New Morphology in Copolymer Melts. Macromolecules 2014. [DOI: 10.1021/ma5016352] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael G. Fischer
- Institut
für Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstr. 7B, 91058 Erlangen, Germany
- Applied Maths, Research School of Physics & Engineering, The Australian National University, Canberra ACT 0200, Australia
- Adolphe Merkle
Institute, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Liliana de Campo
- Applied Maths, Research School of Physics & Engineering, The Australian National University, Canberra ACT 0200, Australia
- Australian
National Science and Technology Organisation, Bragg Institute, New
Illawarra Road, Lucas Heights NSW 2234, Australia
| | | | - Stephen T. Hyde
- Applied Maths, Research School of Physics & Engineering, The Australian National University, Canberra ACT 0200, Australia
| | - Gerd E. Schröder-Turk
- Institut
für Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstr. 7B, 91058 Erlangen, Germany
- Applied Maths, Research School of Physics & Engineering, The Australian National University, Canberra ACT 0200, Australia
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Abstract
We present coarse-grained simulations of the self-assembly of 3-armed ABC star polyphiles. In systems of star polyphiles with two arms of equal length the simulations corroborate and expand previous findings from related miktoarm star terpolymer systems on the formation of patterns containing columnar domains whose sections are 2D planar tilings. However, the systematic variation of face topologies as the length of the third (unequal) arm is varied differs from earlier findings regarding the compositional dependence. We explore 2D 3-colored foams to establish the optimal patterns based on interfacial energy alone. A generic construction algorithm is described that accounts for all observed 2D tiling patterns and suggests other patterns likely to be found beyond the range of the simulations reported here. Patterns resulting from this algorithm are relaxed using Surface Evolver calculations to form 2D foams with minimal interfacial length as a function of composition. This allows us to estimate the interfacial enthalpic contributions to the free energy of related star molecular assemblies assuming strong segregation. We compare the resulting phase sequence with a number of theoretical results from particle-based simulations and field theory, allowing us to tease out relative enthalpic and entropic contributions as a function of the chain lengths making up the star molecules. Our results indicate that a richer polymorphism is to be expected in systems not dominated by chain entropy. Further, analysis of corresponding planar tiling patterns suggests that related two-periodic columnar structures are unlikely hypothetical phases in 4-arm star polyphile melts in the absence of sufficient arm configurational freedom for minor domains to form lens-shaped di-gons, which require higher molecular weight polymeric arms. Finally, we discuss the possibility of forming a complex tiling pattern that is a quasi-crystalline approximant for 3-arm star polyphiles with unequal arm lengths.
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34
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Kirkensgaard JJK, Evans ME, de Campo L, Hyde ST. Hierarchical self-assembly of a striped gyroid formed by threaded chiral mesoscale networks. Proc Natl Acad Sci U S A 2014; 111:1271-6. [PMID: 24474747 PMCID: PMC3910609 DOI: 10.1073/pnas.1316348111] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Numerical simulations reveal a family of hierarchical and chiral multicontinuous network structures self-assembled from a melt blend of Y-shaped ABC and ABD three-miktoarm star terpolymers, constrained to have equal-sized A/B and C/D chains, respectively. The C and D majority domains within these patterns form a pair of chiral enantiomeric gyroid labyrinths (srs nets) over a broad range of compositions. The minority A and B components together define a hyperbolic film whose midsurface follows the gyroid minimal surface. A second level of assembly is found within the film, with the minority components also forming labyrinthine domains whose geometry and topology changes systematically as a function of composition. These smaller labyrinths are well described by a family of patterns that tile the hyperbolic plane by regular degree-three trees mapped onto the gyroid. The labyrinths within the gyroid film are densely packed and contain either graphitic hcb nets (chicken wire) or srs nets, forming convoluted intergrowths of multiple nets. Furthermore, each net is ideally a single chiral enantiomer, induced by the gyroid architecture. However, the numerical simulations result in defect-ridden achiral patterns, containing domains of either hand, due to the achiral terpolymeric starting molecules. These mesostructures are among the most topologically complex morphologies identified to date and represent an example of hierarchical ordering within a hyperbolic pattern, a unique mode of soft-matter self-assembly.
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Affiliation(s)
| | - Myfanwy E. Evans
- Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstrasse 7B, 91058 Erlangen, Germany; and
| | - Liliana de Campo
- Department of Applied Mathematics, Research School of Physical Sciences, Australian National University, Canberra, ACT 0200, Australia
| | - Stephen T. Hyde
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Department of Applied Mathematics, Research School of Physical Sciences, Australian National University, Canberra, ACT 0200, Australia
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35
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Speder J, Altmann L, Bäumer M, Kirkensgaard JJK, Mortensen K, Arenz M. The particle proximity effect: from model to high surface area fuel cell catalysts. RSC Adv 2014. [DOI: 10.1039/c4ra00261j] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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36
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Buldo P, Kirkensgaard JJK, Wiking L. Crystallization mechanisms in cream during ripening and initial butter churning. J Dairy Sci 2013; 96:6782-6791. [PMID: 24035028 DOI: 10.3168/jds.2012-6066] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 07/27/2013] [Indexed: 11/19/2022]
Abstract
The temperature treatment of cream is the time-consuming step in butter production. A better understanding of the mechanisms leading to partial coalescence, such as fat crystallization during ripening and churning of the cream, will contribute to optimization of the production process. In this study, ripening and churning of cream were performed in a rheometer cell and the mechanisms of cream crystallization during churning of the cream, including the effect of ripening time, were investigated to understand how churning time and partial coalescence are affected. Crystallization mechanisms were studied as function of time by differential scanning calorimetry, nuclear magnetic resonance and by X-ray scattering. Microstructure formation was investigated by small deformation rheology and static light scattering. The study demonstrated that viscosity measurements can be used to detect phase inversion of the emulsion during churning of the cream in a rheometer cell. Longer ripening time (e.g., 5h vs. 0 h) resulted in larger butter grains (91 vs. 52 µm), higher viscosity (5.3 vs. 1.3 Pa · s), and solid fat content (41 vs. 13%). Both ripening and churning time had an effect on the thermal behavior of the cream. Despite the increase in solid fat content, no further changes in crystal polymorphism and in melting behavior were observed after 1h of ripening and after churning. The churning time significantly decreased after 0.5h of ripening, from 22.9 min for the cream where no ripening was applied to 16.23 min. Therefore, the crystallization state that promotes partial coalescence (i.e., aggregation of butter grains) is obtained within the first hour of cream ripening at 10 °C. The present study adds knowledge on the fundamental processes of crystallization and polymorphism of milk fat occurring during ripening and churning of cream. In addition, the dairy industry will benefit from these insights on the optimization of butter manufacturing.
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Affiliation(s)
- Patrizia Buldo
- Department of Food Science, Aarhus University, Blichers Allé 20, PO Box 50, 8830 Tjele, Denmark
| | - Jacob J K Kirkensgaard
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - Lars Wiking
- Department of Food Science, Aarhus University, Blichers Allé 20, PO Box 50, 8830 Tjele, Denmark.
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Speder J, Altmann L, Roefzaad M, Bäumer M, Kirkensgaard JJK, Mortensen K, Arenz M. Pt based PEMFC catalysts prepared from colloidal particle suspensions – a toolbox for model studies. Phys Chem Chem Phys 2013; 15:3602-8. [DOI: 10.1039/c3cp50195g] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Posselt D, Nagy G, Kirkensgaard JJK, Holm JK, Aagaard TH, Timmins P, Rétfalvi E, Rosta L, Kovács L, Garab G. Small-angle neutron scattering study of the ultrastructure of chloroplast thylakoid membranes - periodicity and structural flexibility of the stroma lamellae. Biochim Biophys Acta 2012; 1817:1220-8. [PMID: 22306529 DOI: 10.1016/j.bbabio.2012.01.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/30/2011] [Accepted: 01/20/2012] [Indexed: 01/30/2023]
Abstract
The multilamellar organization of freshly isolated spinach and pea chloroplast thylakoid membranes was studied using small-angle neutron scattering. A broad peak at ~0.02Å(-1) is ascribed to diffraction from domains of ordered, unappressed stroma lamellae, revealing a repeat distance of 294ű7Å in spinach and 345ű11Å in pea. The peak position and hence the repeat distance of stroma lamellae is strongly dependent on the osmolarity and the ionic strength of the suspension medium, as demonstrated by varying the sorbitol and the Mg(++)-concentration in the sample. For pea thylakoid membranes, we show that the repeat distance decreases when illuminating the sample with white light, in accordance with our earlier results on spinach, also regarding the observation that addition of an uncoupler prohibits the light-induced structural changes, a strong indication that these changes are driven by the transmembrane proton gradient. We show that the magnitude of the shrinkage is strongly dependent on light intensity and that the repeat distance characteristic of the dark state after illumination is different from the initial dark state. Prolonged strong illumination leads to irreversible changes and swelling as reflected in increased repeat distances. The observed reorganizations are discussed within the frames of the current structural models of the granum-stroma thylakoid membrane assembly and the regulatory mechanisms in response to variations in the environmental conditions in vivo. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- Dorthe Posselt
- Department of Science, Systems and Models, Roskilde University, Roskilde, Denmark.
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de Campo L, Varslot T, Moghaddam MJ, Kirkensgaard JJK, Mortensen K, Hyde ST. A novel lyotropic liquid crystal formed by triphilic star-polyphiles: hydrophilic/oleophilic/fluorophilic rods arranged in a 12.6.4. tiling. Phys Chem Chem Phys 2011; 13:3139-52. [DOI: 10.1039/c0cp01201g] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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