Novel Structural Changes during Temperature-Induced Self-Assembling and Gelation of PLGA-PEG-PLGA Triblock Copolymer in Aqueous Solutions
| Autor: | Kaizheng Zhu, Sara Bekhradnia, Sverre Arne Sande, Neda Khameh Khorshid, Bo Nyström, Kenneth D. Knudsen |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Polymers and Plastics Bioengineering Biocompatible Materials 02 engineering and technology 010402 general chemistry 01 natural sciences Micelle Polyethylene Glycols Biomaterials chemistry.chemical_compound Polymer chemistry PEG ratio Materials Chemistry Copolymer Polyglactin 910 chemistry.chemical_classification Aqueous solution technology industry and agriculture Temperature Water Hydrogels Polymer 021001 nanoscience & nanotechnology Small-angle neutron scattering 0104 chemical sciences Solutions PLGA chemistry Chemical engineering 0210 nano-technology Rheology Ethylene glycol Hydrophobic and Hydrophilic Interactions Biotechnology |
| Zdroj: | Macromolecular bioscience. 16(12) |
| ISSN: | 1616-5195 |
| Popis: | The thermoresponsive amphiphilic block copolymer poly(d,l-lactic acid-co-glycolic acid)-block-poly(ethylene glycol)-block-poly(d,l-lactic acid-co-glycolic acid) (PLGA-PEGn-PLGA), which exhibits a reversible temperature-induced sol–gel transition at higher polymer concentrations in aqueous solution has attached a great deal of interest because of its potential in biomedical applications. In the present work, the length of the hydrophobic PLGA blocks is kept constant, whereas the length of the hydrophilic PEG block is altered and this variation has a pronounced impact on the phase behavior of the aqueous samples and the structure of the polymer. A short PEG block promotes gelation at a low temperature, whereas a longer PEG block shifts the gelation point to higher temperature. By using a combination of turbidity, rheology, and small angle neutron scattering (SANS) methods, the authors have revealed dramatic temperature effects. In dilute solution, the SANS experiments expose asymmetric ellipsoid structures for the copolymer with the short PEG-spacer, whereas spherical core–shell structure is observed for the polymer with long PEG-spacer. In the semidilute concentration regime, SANS measurements disclose similar profiles for the two copolymers. In a broad temperature interval, the transition from spherical core–shell micelles to cylindrical structure and packing of cylinders is observed. |
| Databáze: | OpenAIRE |
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