Enhanced resistance and reversible temperature - triggered volume change of giant vesicles enclosing Poly ( N - isopropylacrylamide ) solutions or gels
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Enhanced resistance and reversible temperaturetriggered volume change of giant vesicles enclosing Poly(N-isopropylacrylamide) solutions or gels. MAGALIE FAIVRE, CLEMENT CAMPILLO, BRIGITTE PEPIN-DONAT, ANNIE VIALLAT 1 Laboratoire de Spectrométrie Physique, UMR C5588 (CNRS) Université Joseph Fourier 38402 Saint Martin d’Hères, France. 2 Laboratoire de Physique des Métaux Synthétiques, UMR 5819, DRFMC, CEA-Grenoble, France [email protected], fax : 33 491 75 73 28, phone : 33 491 74 40 47; [email protected], fax : 33 438 785 113, phone : 33 491 74 40 47 presented in the 42nd Meeting of the German Colloid Society September 26 28, 2005, Aachen, Germany Abstract We prepared giant unilamellar vesicles (GUVs) enclosing solutions or covalent gels of Poly(Nisopropylacrylamide) (PolyNipam). Concentrated suspensions of GUVs were prepared by applying an alternative field on a lipid film hydrated by a monomer solution containing N-isopropylacrylamide, crosslinker (N,N’methylene-bis-acrylamide), initiator and sucrose. Vesicle inner medium was polymerised and cross-linked by U.V.irradiation of the suspension, yielding viscous vesicles enclosing a solution of linear PolyNipam chains (when no bisacrylamide was used) or elastic vesicles filled with a covalent PolyNipam gel. We show that gel-filled vesicles are responsive systems triggered by the temperature: they shrink, reducing by a factor eight their volume below the critical temperature (32°C in water, lower in presence of sucrose) and re-swell in a reversible and reproducible way upon decreasing temperature. In both cases, we show that the vesicle lipid membrane interacts with the internal polymer, resulting in an strong resistance of the vesicles to external mechanical stresses (enhanced tension of lysis).
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تاریخ انتشار 2008