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Späth A, Graf-Zeiler BA, Paradossi G, Ghugare S, Tzvetkov G, Fink RH. Quantitative X-ray microscopic analysis of individual thermoresponsive microgel particles in aqueous solution. RSC Adv 2016. [DOI: 10.1039/c6ra20142c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The temperature dependent phase transition of individual thermoresponsive microgel particles in aqueous solution has been studied by high resolution soft X-ray transmission microscopy (STXM).
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Affiliation(s)
- Andreas Späth
- Physikalische Chemie II
- ICMM
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- 91058 Erlangen
- Germany
| | - Birgit A. Graf-Zeiler
- Physikalische Chemie II
- ICMM
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- 91058 Erlangen
- Germany
| | - Gaio Paradossi
- Dipartimento di Scienze e Tecnologie Chimiche
- Università di Roma Tor Vergata
- 00133 Roma
- Italy
| | - Shivkumar Ghugare
- Dipartimento di Scienze e Tecnologie Chimiche
- Università di Roma Tor Vergata
- 00133 Roma
- Italy
| | - George Tzvetkov
- Department of Inorganic Chemistry
- Faculty of Chemistry
- University of Sofia
- 1164 Sofia
- Bulgaria
| | - Rainer H. Fink
- Physikalische Chemie II
- ICMM
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
- 91058 Erlangen
- Germany
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Graf-Zeiler B, Fink RH, Tzvetkov G. In Situ Synchrotron Radiation X-Ray Microspectroscopy of Polymer Microcontainers. Chemphyschem 2011; 12:3503-9. [PMID: 21853515 DOI: 10.1002/cphc.201100370] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Indexed: 11/09/2022]
Affiliation(s)
- Birgit Graf-Zeiler
- Department Chemie und Pharmazie, Physikalische Chemie II, Universität Erlangen-Nürnberg and Interdisciplinary Center for Molecular Materials (ICMM), Egerlandstrasse 3, 91058 Erlangen, Germany
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Li J, Hitchcock AP, Stöver HDH. Pickering emulsion templated interfacial atom transfer radical polymerization for microencapsulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:17926-17935. [PMID: 21028818 DOI: 10.1021/la102867v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This Article describes a new microencapsulation method based on a Pickering emulsion templated interfacial atom transfer radical polymerization (PETI-ATRP). Cationic LUDOX CL nanoparticles were coated electrostatically with an anionic polymeric ATRP initiator, poly(sodium styrene sulfonate-co-2-(2-bromoisobutyryloxy)ethyl methacrylate) (PSB), prepared by radical copolymerization of sodium styrene sulfonate and 2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM). The resulting PSB-modified CL particles were surface active and could be used to stabilize oil-in-water Pickering emulsions. ATRP of water-soluble cross-linking monomers, confined to the oil-water interface by the surface-bound PSB, then led to nanoparticle/polymer composite shells. This method allowed encapsulation of core solvents (xylene, hexadecane, perfluoroheptane) with different solubility parameters. The microcapsule (MC) wall chemistry could accommodate different monomers, demonstrating the versatility of this method. Double-walled MCs were formed by sequentially carrying out PETI-ATRP and in situ polymerization of encapsulated monomers. The double-walled structure was verified by both transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM).
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Affiliation(s)
- Jian Li
- Department of Chemistry & Chemical Biology, McMaster University, Hamilton, ON, Canada L8S 4M1
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Plaschke M, Rothe J, Armbruster MK, Denecke MA, Naber A, Geckeis H. Humic acid metal cation interaction studied by spectromicroscopy techniques in combination with quantum chemical calculations. JOURNAL OF SYNCHROTRON RADIATION 2010; 17:158-165. [PMID: 20157266 DOI: 10.1107/s0909049509048742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 11/16/2009] [Indexed: 05/28/2023]
Abstract
Humic acids (HA) have a high binding capacity towards traces of toxic metal cations, thus affecting their transport in aquatic systems. Eu(III)-HA aggregates are studied by synchrotron-based scanning transmission X-ray microscopy (STXM) at the carbon K-edge and laser scanning luminescence microscopy (LSLM) at the (5)D(0) --> (7)F(1,2) fluorescence emission lines. Both methods provide the necessary spatial resolution in the sub-micrometre range to resolve characteristic aggregate morphologies: optically dense zones embedded in a matrix of less dense material in STXM images correspond to areas with increased Eu(III) luminescence yield in the LSLM micrographs. In the C 1s-NEXAFS of metal-loaded polyacrylic acid (PAA), used as a HA model compound, a distinct complexation effect is identified. This effect is similar to trends observed in the dense fraction of HA/metal cation aggregates. The strongest complexation effect is observed for the Zr(IV)-HA/PAA system. This effect is confirmed by quantum chemical calculations performed at the ab initio level for model complexes with different metal centres and complex geometries. Without the high spatial resolution of STXM and LSLM and without the combination of molecular modelling with experimental results, the different zones indicating a ;pseudo'-phase separation into strong complexing domains and weaker complexing domains of HA would never have been identified. This type of strategy can be used to study metal interaction with other organic material.
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Affiliation(s)
- M Plaschke
- Karlsruher Institut für Technologie (KIT), Institut für Nukleare Entsorgung, Eggenstein-Leopoldshafen, Germany.
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Graf C, Meinke M, Gao Q, Hadam S, Raabe J, Sterry W, Blume-Peytavi U, Lademann J, Rühl E, Vogt A. Qualitative detection of single submicron and nanoparticles in human skin by scanning transmission x-ray microscopy. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:021015. [PMID: 19405728 DOI: 10.1117/1.3078811] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
First results on single particle detection in human skin samples by x-ray microscopy are reported. 94+/-6 and 161+/-13 nm gold core particles with silica shells and 298+/-11 nm silica particles coated with a gold shell on ultramicrotome sections of human skin were determined. The particles were applied on fresh intact skin samples, which were sectioned prior to imaging. After screening the sections by conventional microscopy techniques, defined areas of interest were qualitatively investigated by scanning transmission x-ray microscopy at the Swiss Light Source. In studies on the percutaneous penetration of 161+/-13 nm particles on human skin samples, x-ray microscopy yielded high-resolution images of single particles spreading on the superficial layer of the stratum corneum and on the epithelium in superficial parts of hair follicles. No deeper penetration was observed. The present work using x-ray microscopy provides the unique opportunity to study qualitative penetration processes and membrane-particle interactions on the level of single particles. This goes beyond present approaches using optical microscopy. Further improvement of this approach will allow one to study particles with different physicochemical properties and surface modifications, including responses of the exposed tissue.
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Affiliation(s)
- Christina Graf
- Freie Universitat Berlin, Physikalische und Theoretische Chemie, Takustr. 3, 14195 Berlin, Germany.
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Leung BO, Hitchcock AP, Brash JL, Scholl A, Doran A. Phase Segregation in Polystyrene−Polylactide Blends. Macromolecules 2009. [DOI: 10.1021/ma802176b] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bonnie O. Leung
- BIMR, McMaster University, Hamilton, ON, Canada L8S 4M1; School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4M1; and Advanced Light Source, Berkeley Laboratory, Berkeley, California 94720
| | - Adam P. Hitchcock
- BIMR, McMaster University, Hamilton, ON, Canada L8S 4M1; School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4M1; and Advanced Light Source, Berkeley Laboratory, Berkeley, California 94720
| | - John L. Brash
- BIMR, McMaster University, Hamilton, ON, Canada L8S 4M1; School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4M1; and Advanced Light Source, Berkeley Laboratory, Berkeley, California 94720
| | - Andreas Scholl
- BIMR, McMaster University, Hamilton, ON, Canada L8S 4M1; School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4M1; and Advanced Light Source, Berkeley Laboratory, Berkeley, California 94720
| | - Andrew Doran
- BIMR, McMaster University, Hamilton, ON, Canada L8S 4M1; School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4M1; and Advanced Light Source, Berkeley Laboratory, Berkeley, California 94720
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Tzvetkov G, Fernandes P, Wenzel S, Fery A, Paradossi G, Fink RH. Soft X-ray induced modifications of PVA-based microbubbles in aqueous environment: a microspectroscopy study. Phys Chem Chem Phys 2009; 11:1098-104. [DOI: 10.1039/b814946a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fernandes PAL, Tzvetkov G, Fink RH, Paradossi G, Fery A. Quantitative analysis of scanning transmission X-ray microscopy images of gas-filled PVA-based microballoons. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13677-13682. [PMID: 18980347 DOI: 10.1021/la801898t] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the quantitative analysis of scanning transmission X-ray microscopy (STXM) images of gas-filled, poly(vinyl alcohol) (PVA)-based microballoons (MB) in a water environment. A model for the transmitted intensity is proposed on the basis of a perfect spherical shell stabilizing the microballoon. An extension of this model to take into account the deformation of the MBs is also presented. Taking into consideration a density gradient of the shell and the STXM resolution, we were able to explain very precisely two types of experimental STXM profiles observed on gas-filled MBs. This enables the detailed characterization of MB properties such as radius and wall thickness and the determination of their wall density with unprecedented high resolution.
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Affiliation(s)
- Paulo A L Fernandes
- Physikalische Chemie II, Universitiit Bayreuth, Universitätsstrasse 10, D-95447 Bayreuth, Germany.
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Tzvetkov G, Graf B, Fernandes P, Fery A, Cavalieri F, Paradossi G, Fink RH. In situ characterization of gas-filled microballoons using soft X-ray microspectroscopy. SOFT MATTER 2008; 4:510-514. [PMID: 32907213 DOI: 10.1039/b715392a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this study we describe the first direct, real-space characterization of a novel type of poly(vinyl alcohol) (PVA) based microballoons in aqueous environment using scanning transmission X-ray microscopy (STXM). From the oxygen K-edge near-edge X-ray absorption fine structure (NEXAFS) spectra taken from the microballoon interiors we could unambiguously distinguish between water- and air-filled particles. We also demonstrate that STXM imaging below and above the O K-edge (520 eV and 550 eV) can provide unique information on the composition of microballoons in water. It was found that the particular microballoon system investigated here has a remarkable high stability and is able to contain gases for more than 6 months, making it well suited for biomedical applications.
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Affiliation(s)
- George Tzvetkov
- Physikalische Chemie II, Friedrich-Alexander Universität Erlangen-Nürnberg, Egerlandstrasse 3, D-91058 Erlangen, Germany. and Swiss Light Source, Paul Scherrer Institut, 5232 Villigen - PSI, Switzerland
| | - Birgit Graf
- Physikalische Chemie II, Friedrich-Alexander Universität Erlangen-Nürnberg, Egerlandstrasse 3, D-91058 Erlangen, Germany.
| | - Paulo Fernandes
- Physikalische Chemie II, Universität Bayreuth, Universitätsstraße 10, D-95447 Bayreuth, Germany
| | - Andreas Fery
- Physikalische Chemie II, Universität Bayreuth, Universitätsstraße 10, D-95447 Bayreuth, Germany
| | - Francesca Cavalieri
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Roma, Italy
| | - Gaio Paradossi
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Roma, Italy
| | - Rainer H Fink
- Physikalische Chemie II, Friedrich-Alexander Universität Erlangen-Nürnberg, Egerlandstrasse 3, D-91058 Erlangen, Germany. and Interdisciplinary Center for Molecular Materials (ICMM), Egerlandstrasse 3, D-91058 Erlangen, Germany
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