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Time-Resolved SAXS Studies of the Kinetics of Thermally Triggered Release of Encapsulated Silica Nanoparticles from Block Copolymer Vesicles
[Image: see text] Silica-loaded poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) diblock copolymer vesicles are prepared in the form of concentrated aqueous dispersions via polymerization-induced self-assembly (PISA). As the concentration of silica nanoparticles present during the...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American
Chemical Society
2017
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5472368/ https://www.ncbi.nlm.nih.gov/pubmed/28626247 http://dx.doi.org/10.1021/acs.macromol.7b00475 |
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author | Mable, Charlotte J. Derry, Matthew J. Thompson, Kate L. Fielding, Lee A. Mykhaylyk, Oleksandr O. Armes, Steven P. |
author_facet | Mable, Charlotte J. Derry, Matthew J. Thompson, Kate L. Fielding, Lee A. Mykhaylyk, Oleksandr O. Armes, Steven P. |
author_sort | Mable, Charlotte J. |
collection | PubMed |
description | [Image: see text] Silica-loaded poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) diblock copolymer vesicles are prepared in the form of concentrated aqueous dispersions via polymerization-induced self-assembly (PISA). As the concentration of silica nanoparticles present during the PISA synthesis is increased up to 35% w/w, higher degrees of encapsulation of this component within the vesicles can be achieved. After centrifugal purification to remove excess non-encapsulated silica nanoparticles, SAXS, DCP, and TGA analysis indicates encapsulation of up to hundreds of silica nanoparticles per vesicle. In the present study, the thermally triggered release of these encapsulated silica nanoparticles is examined by cooling to 0 °C for 30 min, which causes in situ vesicle dissociation. Transmission electron microscopy studies confirm the change in diblock copolymer morphology and also enable direct visualization of the released silica nanoparticles. Time-resolved small-angle X-ray scattering is used to quantify the extent of silica release over time. For an initial silica concentration of 5% w/w, cooling induces a vesicle-to-sphere transition with subsequent nanoparticle release. For higher silica concentrations (20 or 30% w/w) cooling only leads to perforation of the vesicle membranes, but silica nanoparticles are nevertheless released through the pores. For vesicles prepared in the presence of 30% w/w silica, the purified silica-loaded vesicles were cooled to 0 °C for 30 min, and SAXS patterns were collected every 15 s. A new SAXS model has been developed to determine both the mean volume fraction of encapsulated silica within the vesicles and the scattering length density. Satisfactory data fits to the experimental SAXS patterns were obtained using this model. |
format | Online Article Text |
id | pubmed-5472368 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | American
Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-54723682017-06-16 Time-Resolved SAXS Studies of the Kinetics of Thermally Triggered Release of Encapsulated Silica Nanoparticles from Block Copolymer Vesicles Mable, Charlotte J. Derry, Matthew J. Thompson, Kate L. Fielding, Lee A. Mykhaylyk, Oleksandr O. Armes, Steven P. Macromolecules [Image: see text] Silica-loaded poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) diblock copolymer vesicles are prepared in the form of concentrated aqueous dispersions via polymerization-induced self-assembly (PISA). As the concentration of silica nanoparticles present during the PISA synthesis is increased up to 35% w/w, higher degrees of encapsulation of this component within the vesicles can be achieved. After centrifugal purification to remove excess non-encapsulated silica nanoparticles, SAXS, DCP, and TGA analysis indicates encapsulation of up to hundreds of silica nanoparticles per vesicle. In the present study, the thermally triggered release of these encapsulated silica nanoparticles is examined by cooling to 0 °C for 30 min, which causes in situ vesicle dissociation. Transmission electron microscopy studies confirm the change in diblock copolymer morphology and also enable direct visualization of the released silica nanoparticles. Time-resolved small-angle X-ray scattering is used to quantify the extent of silica release over time. For an initial silica concentration of 5% w/w, cooling induces a vesicle-to-sphere transition with subsequent nanoparticle release. For higher silica concentrations (20 or 30% w/w) cooling only leads to perforation of the vesicle membranes, but silica nanoparticles are nevertheless released through the pores. For vesicles prepared in the presence of 30% w/w silica, the purified silica-loaded vesicles were cooled to 0 °C for 30 min, and SAXS patterns were collected every 15 s. A new SAXS model has been developed to determine both the mean volume fraction of encapsulated silica within the vesicles and the scattering length density. Satisfactory data fits to the experimental SAXS patterns were obtained using this model. American Chemical Society 2017-05-26 2017-06-13 /pmc/articles/PMC5472368/ /pubmed/28626247 http://dx.doi.org/10.1021/acs.macromol.7b00475 Text en Copyright © 2017 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
spellingShingle | Mable, Charlotte J. Derry, Matthew J. Thompson, Kate L. Fielding, Lee A. Mykhaylyk, Oleksandr O. Armes, Steven P. Time-Resolved SAXS Studies of the Kinetics of Thermally Triggered Release of Encapsulated Silica Nanoparticles from Block Copolymer Vesicles |
title | Time-Resolved SAXS Studies of the Kinetics of Thermally
Triggered Release of Encapsulated Silica Nanoparticles from Block
Copolymer Vesicles |
title_full | Time-Resolved SAXS Studies of the Kinetics of Thermally
Triggered Release of Encapsulated Silica Nanoparticles from Block
Copolymer Vesicles |
title_fullStr | Time-Resolved SAXS Studies of the Kinetics of Thermally
Triggered Release of Encapsulated Silica Nanoparticles from Block
Copolymer Vesicles |
title_full_unstemmed | Time-Resolved SAXS Studies of the Kinetics of Thermally
Triggered Release of Encapsulated Silica Nanoparticles from Block
Copolymer Vesicles |
title_short | Time-Resolved SAXS Studies of the Kinetics of Thermally
Triggered Release of Encapsulated Silica Nanoparticles from Block
Copolymer Vesicles |
title_sort | time-resolved saxs studies of the kinetics of thermally
triggered release of encapsulated silica nanoparticles from block
copolymer vesicles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5472368/ https://www.ncbi.nlm.nih.gov/pubmed/28626247 http://dx.doi.org/10.1021/acs.macromol.7b00475 |
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