Ce travail a été soutenu financièrement par la Fondation national suisse (PNR 62 - Matériaux intelligents). Également reconnu est le support de B. Hanselmann, K. Kehl, U. Schütz et B. Leuthold.

Une. La polymérisation par plasma initié <ol><li> Préparation de la solution de monomère. <ol><li> Dissoudre HEMA (100 ml; 0,718 mole) dans 200 ml d&#39;eau et laver 3 fois avec de l&#39;hexane (100 ml) dans une ampoule à décanter. Saturer la phase aqueuse avec du chlorure de sodium et on extrait le HEMA avec de l&#39;éther diéthylique (50 ml). Sécher la phase organique sur MgSO 4 et éliminer le solvant sous vide (100 mbar, 40 ° C). Distiller le HEMA sous pression réduite (15 mbar; 99 ° C). </li><li> Préparer une solution 0,62 M de méthanol de l&#39;HEMA sans inhibiteur produit dans la section 1.1.1. Verser 30 ml de la solution dans un ballon à un seul col et à éliminer l&#39;oxygène par barbotage d&#39;Ar à travers la solution pendant 1 heure. </li></ol></li><li> Polymérisation induite par surface. <ol><li> La position des deux membranes en polycarbonate côté de l&#39;autre dans la chambre de plasma (figure 2). Placer le côté brillant de la membrane tournée vers la phase gazeuse. </li><li> Connectez la chambre à plasma de ahaute vide (20 mbar) pendant 5 min. Fermer la vanne à vide et ouvrir l&#39;autre soupape, qui est relié à l&#39;argon et de l&#39;oxygène gazeux et de purger la chambre avec ce mélange pendant 2 heures à 15 sccm d&#39;argon et de 2,5 sccm d&#39;oxygène. </li><li> Amorcer le plasma et de réduire la puissance à la puissance souhaitée (par membrane de polycarbonate: 12 W) et pour traiter les membranes 4 min avec le plasma. Raccorder la solution de monomère avec la chambre par l&#39;ouverture de la vanne correspondante. Eteignez le plasma et évacuer la chambre. </li><li> Raccorder la solution de monomère avec la chambre par l&#39;ouverture de la vanne correspondante et verser la solution dans la chambre. S&#39;assurer que les membranes sont recouvertes de la solution de monomère. Ouvrir la vanne reliée à l&#39;argon et stocker le mélange réactionnel pendant 12 heures à 20 ° C (salle climatisée). </li><li> Retirer la solution de monomère. Laver les membranes avec du methanol dans un bain à ultrasons pendant 5 min. Répétez la procédure de lavage avec de l&#39;eau. </li><li> Sécher la membranesous vide sur des tamis moléculaires pendant 2 heures. </li></ol></li></ol> 2. Modification ultérieure des membranes enduites <ol><li> Préparer une solution de spirobenzopyran 1 (figure 1) (100 mg; 0,27 mmol), de N, N-dicyclohexylcarbodiimide (DCC) (55 mg; 0,27 mmol) et de diméthyl-aminopyridine (DMAP) (33 mg, 0,27 mmol) dans du tert-butylmetylether (TBME) (12 ml). </li><li> Placer un barreau protection et une grille de protection dans un ballon à fond rond. Le ballon est séché et inonder le ballon avec de l&#39;argon. </li><li> Verser la solution dans le ballon, suivie de la membrane revêtue. </li><li> Mélanger délicatement à la température ambiante pendant 12 heures. </li><li> Retirer la solution et laver la membrane avec du tert-butylmetylether dans un bain à ultrasons pendant 5 min. Répétez la procédure de lavage avec de l&#39;éthanol et de l&#39;eau. </li><li> Sécher la membrane sous vide sur des tamis moléculaires pendant 2 heures. </li></ol> 3. Les mesures de tension de surface <ol><li&gt; fixer la membrane avec une bande standard sur un joint torique métallique. Positionner une goutte d&#39;eau nanopure (3,3 ul) sur la partie de la surface de la membrane, qui n&#39;est pas en contact avec le joint torique. Mesurer l&#39;angle de contact (CA) à 5 endroits différents de la membrane. </li><li> Pour tester la stabilité à long terme des échantillons, de mesurer les angles de contact à trois points différents des membranes après 0, 1, 2, 3, 7, 14 et 21 jours. </li></ol> 4. Tests de perméabilité des membranes photochromiques <ol><li> Remplir la chambre de récepteur de la cellule de diffusion de Franz avec de l&#39;eau (12 ml). </li><li> Fixer la membrane dans une cellule de diffusion Franz. S&#39;assurer que la membrane est en contact avec l&#39;eau de la chambre de récepteur. Remplir la chambre de donneur (la chambre au-dessus de la membrane) avec une solution aqueuse de caféine (20 mM; 3,0 ml). Irradier la membrane du haut de la chambre de donneur avec lumière blanche (Figure 3). Prélever des échantillons (200 pi) de la cellule réceptrice; for des membranes de polycarbonate piste tranchant avec un diamètre de pores de 200 nm, prélever des échantillons toutes les 10 min. </li><li> Répétez l&#39;expérience comme décrit dans l&#39;étape 4.2. irradier la membrane mais avec une lumière UV (366 nm, 80 W / m 2) au cours de l&#39;essai de perméabilité entier. </li><li> Détermination de la concentration en caféine des échantillons prélevés. <ol><li> Tracer la courbe d&#39;étalonnage avec des 15 concentrations différentes de caféine (entre 0,05 mg / ml et 1,5 mM / L) en utilisant un UV / Vis spectromètre. Calibrer à 293 nm. </li><li> Déterminer la concentration de chacun des échantillons prélevés à l&#39;aide de la courbe d&#39;étalonnage. </li><li> Tracer la concentration déterminée vs. le temps des échantillons prélevés. Faites un ajustement linéaire par les points et déterminer Ac de la pente. </li></ol></li></ol>

<ol>
	<li>d'Agostino, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Basic Approaches to Plasma Production and Control. , (2008).</li><li>Liston, E. M., Martinu, L., Wertheimer, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+surface+modification+of+polymers+for+improved+adhesion:+a+critical+review.">Plasma surface modification of polymers for improved adhesion: a critical review.</a> J. Adh. Sci. Technol. 7 (10), 1091-1127 (1993).</li><li>Siow, K. S., Britcher, L., Kumar, S., Griesser, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+Methods+for+the+Generation+of+Chemically+Reactive+Surfaces+for+Biomolecule+Immobilization+and+Cell+Colonization+-+A+Review.+Process.">Plasma Methods for the Generation of Chemically Reactive Surfaces for Biomolecule Immobilization and Cell Colonization - A Review. Process.</a> Polymers. 3 (6-7), 392-418 (2006).</li><li>Hossain, M. M., Hegemann, D., Herrmann, A. S., Chabrecek, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contact+angle+determination+on+plasma-treated+poly(ethylene+terephthalate)+fabrics+and+foils.">Contact angle determination on plasma-treated poly(ethylene terephthalate) fabrics and foils.</a> Appl. Polymer Sci. 102 (2), 1452-1458 (2006).</li><li>Guimond, S., Hanselmann, B., Amberg, M., Hegemann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+functionalization+of+textiles:+Specifics+and+possibilities.">Plasma functionalization of textiles: Specifics and possibilities.</a> Pure Appl. Chem. 82 (6), 1239-1245 (2010).</li><li>Lymberopoulos, D. P., Economou, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+and+simulation+of+glow+discharge+plasma+reactors.">Modeling and simulation of glow discharge plasma reactors.</a> Journal of Vacuum Sci. Technol. A Vacuum Surf. Films. 12 (4), 1229-1236 (1994).</li><li>Hegemann, D., Brunner, H., Oehr, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasma+treatment+of+polymers+for+surface+and+adhesion+improvement.">Plasma treatment of polymers for surface and adhesion improvement.</a> Nuclear Instr. Methods Phys. Res. B Interact. Atoms. 208, 281-286 (2003).</li><li>&#216;iseth, S. K., Krozer, A., Kasemo, B., Lausmaa, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+modification+of+spin-coated+high-density+polyethylene+films+by+argon+and+oxygen+glow+discharge+plasma+treatments.">Surface modification of spin-coated high-density polyethylene films by argon and oxygen glow discharge plasma treatments.</a> Appl. Surf. Sci. 202 (1-2), 92-103 (2002).</li><li>Choi, W. -. K., Koh, S. -. K., Jung, H. -. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+chemical+reaction+between+polycarbonate+and+kilo-electron-volt+energy+Ar[sup+++]+ion+in+oxygen+environment.">Surface chemical reaction between polycarbonate and kilo-electron-volt energy Ar[sup + ] ion in oxygen environment.</a> J. Vacuum Sci. Technol. A Vacuum Surf. Films. 14 (4), 2366-2371 (1996).</li><li>Kitova, S., Minchev, M., Danev, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RF+plasma+treatment+of+polycarbonate+substrates.">RF plasma treatment of polycarbonate substrates.</a> Optoelectron. Adv. Mater. 7 (5), 2607-2612 (2005).</li><li>Friedrich, J. F., Mix, R., Schulze, R. D., Meyer-Plath, A., Joshi, R., Wettmarshausen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+plasma+techniques+for+polymer+surface+modification+with+monotype+functional+groups.">New plasma techniques for polymer surface modification with monotype functional groups.</a> Plasma Process. Polymers. 5 (5), 407-423 (2008).</li><li>Baumann, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tuning+the+resistance+of+polycarbonate+membranes+by+plasma-induced+graft+surface+modification.">Tuning the resistance of polycarbonate membranes by plasma-induced graft surface modification.</a> Appl. Surf. Sci. 268, 450-457 (2013).</li><li>Hegemann, D., Hossain, M. M., Balazs, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanostructured+plasma+coatings+to+obtain+multifunctional+textile+surfaces.">Nanostructured plasma coatings to obtain multifunctional textile surfaces.</a> Prog. Org. Coatings. 58 (2-3), 237-240 (2007).</li><li>Gengenbach, T., Vasic, Z., Li, S., Chatelier, R., Griesser, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contributions+of+restructuring+and+oxidation+to+the+aging+of+the+surface+of+plasma+polymers+containing+heteroatoms.">Contributions of restructuring and oxidation to the aging of the surface of plasma polymers containing heteroatoms.</a> Plasmas Polymers. 2 (2), 91-114 (1997).</li><li>Gengenbach, T. R., Chatelier, R. C., Griesser, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+the+Ageing+of+Plasma-deposited+Polymer+Films:+Global+Analysis+of+X-ray+Photoelectron+Spectroscopy+Data.">Characterization of the Ageing of Plasma-deposited Polymer Films: Global Analysis of X-ray Photoelectron Spectroscopy Data.</a> Interface Anal. 24 (4), 271-281 (1996).</li><li>Hirotsu, T., Nakajima, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Water+ethanol+permseparation+by+pervaporation+throught+the+plasma+graft+copolymeric+membranes+of+acrylic+acid+and+acrylamide.">Water ethanol permseparation by pervaporation throught the plasma graft copolymeric membranes of acrylic acid and acrylamide.</a> Appl. Polymer Sci. 36 (1), 177-189 (1988).</li><li>Baumann, L., de Courten, D., Wolf, M., Rossi, R. M., Scherer, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light-Responsive+Caffeine+Transfer+through+Porous+Polycarbonate.">Light-Responsive Caffeine Transfer through Porous Polycarbonate.</a> Appl. Mater. Interf. 5 (13), 5894-5897 (2013).</li><li>Minkin, V. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photo-,+thermo-,+solvato-,+and+electrochromic+spiroheterocyclic+compounds.">Photo-, thermo-, solvato-, and electrochromic spiroheterocyclic compounds.</a> Chem. Rev. 104 (5), 2751-2776 (2004).</li><li>Berkovic, G., Krongauz, V., Weiss, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spiropyrans+and+spirooxazines+for+memories+and+switches.">Spiropyrans and spirooxazines for memories and switches.</a> Chem. Rev. 100 (5), 1741-1753 (2000).</li><li>Vlassiouk, I., Park, C. -. D., Vail, S. A., Gust, D., Smirnov, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+Nanopore+Wetting+by+a+Photochromic+Spiropyran:+A+Light-Controlled+Valve+and+Electrical+Switch.">Control of Nanopore Wetting by a Photochromic Spiropyran: A Light-Controlled Valve and Electrical Switch.</a> Lett. 6 (5), 1013-1017 (2006).</li><li>Baumann, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+light-responsive+porous+polycarbonate+membranes+for+controlled+caffeine+delivery.">Development of light-responsive porous polycarbonate membranes for controlled caffeine delivery.</a> RSC Adv. 3 (45), 23317-23326 (2013).</li><li>Nicoletta, F. P., Cupelli, D., Formoso, P., De Filpo, G., Colella, V., Gugliuzza, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light+Responsive+Polymer+Membranes:+A+Review.">Light Responsive Polymer Membranes: A Review.</a> Membranes. 2 (1), 134-197 (2012).</li></ol>

Les auteurs n&#39;ont rien à révéler.

Le procédé par plasma produit un gaz pourpre, qui est provoquée par l&#39;argon ionisé. Une couleur orangé d&#39;indiquer la présence d&#39;azote à partir d&#39;une fuite indésirable. Le processus de plasma ne se forme pas seulement des radicaux sur la surface, mais aussi attaque la membrane 7,12. Trop de gravure peut modifier le diamètre des pores de manière significative, ce qui pourrait influencer la perméabilité de la membrane. Les conditions de la réaction contrôlée de la configuration pr?...

modification de plasma de matériaux est devenue un processus important dans de nombreux domaines industriels. Nettoyage des surfaces et fonctionnalisation des surfaces sans modification de la propriété apparente de la matière a fait le traitement au plasma un processus essentiel dans la science des surfaces 1-8. Le traitement par plasma de polymères en résulte homolytique clivage de la liaison. Cela conduit à une bordure de la matière polymère et à la formation de surfaces riches radicaux. En utilisant le plasma contenant des molécules d&#39;oxygène, la surface devient riche en oxygène et donc plus hydrophile 9-11. Cependant, le caractère hydrophile des surfaces n&#39;est pas stable dans le temps 12. Afin d&#39;améliorer la stabilité à long terme, la surface traitée au plasma peut être modifié chimiquement après ou pendant le procédé au plasma de 13 à 15. Ce traitement est normalement effectuée par l&#39;addition d&#39;une espèce de monomère réactif dans la phase gazeuse au cours du processus de plasma; ces monomères polymérisent ensuiteparmi les radicaux créés de la surface du polymère. Si la composition de traitement chimique est effectué avec un monomère non volatile, le greffage de polymère doit avoir lieu après la modification de plasma. Afin d&#39;effectuer un greffage contrôlée après les radicaux sont formés sur la surface, une configuration de plasma est décrit, qui permet à la polymérisation induite par plasma-surface à l&#39;initiative de la surface dans une solution dans des conditions contrôlées 12,16. La présentation met l&#39;accent sur ​​la modification de membranes polymères piste tranchant 12,17. En modifiant la tension de surface de ces membranes, le taux de perméabilité peut être modifiée 12. Ce processus propre et rapide permet la création de couches très minces (&lt;5 nm), qui couvrent la surface entière de la membrane, sans modifier la propriété majeure partie de la membrane de polymère. En raison de la limitation de bord pendant le processus de plasma, les diamètres de pores des membranes de la voie tranchant augmentent légèrement 12. Le taux de bordure est depending sur le polymère et a un comportement linéaire. Lors de l&#39;utilisation de monomères ayant des groupes fonctionnels réactifs, les polymères greffés peuvent être en outre fonctionnalisés. Cela est démontré par la modification ultérieure d&#39;une membrane de PHEMA-greffé avec un spiropyrane fonctionnalisé d&#39;acide carboxylique. Il en résulte une surface photochromique, depuis spiropyranne est connu de transformer en une espèce de mérocyanine lorsqu&#39;il est irradié avec une lumière UV. La forme spiropyrane peut être rétablie par l&#39;irradiation de la forme de mérocyanine avec la lumière visible (figure 1) 18,19. Etant donné que la forme mérocyanine est plus polaire que l&#39;état spiropyrane, la tension de surface du revêtement peut être déclenché par la lumière 20. La variation de la tension de surface influence la résistance à la perméabilité de la membrane en direction des solutions aqueuses. La mise en place la façon d&#39;effectuer les essais de perméabilité de ces membranes sensibles à la lumière sera affiché et le changement significatif de la résistance à la perméabilité (i diminuern résistance de perméabilité de 97%) est démontrée. Une telle membrane peut être intégrée dans une installation de distribution de médicaments ou dans des systèmes de détection à puce. <img alt="Figure 1" fo:content-width="5in" fo:src="/files/ftp_upload/51680/51680fig1highres.jpg" src="/files/ftp_upload/51680/51680fig1.jpg" /> Figure 1. Photoisomérisation du composé spirobenzopyran 1.

<table border="0" cellpadding="0" cellspacing="0" style="width:943px;" width="943">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Name of Reagent/ Equipment</td>
			<td style="width:284px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">2-Hydroxyethyl methacrylate, 97%</td>
			<td style="width:284px;">Sigma-Aldrich</td>
			<td style="width:119px;">128635</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Hexane 99%</td>
			<td style="width:284px;">Biosolve</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Magnesium sulfate (MgSO4, anhydrous)</td>
			<td style="width:284px;">Sigma-Aldrich</td>
			<td>M7506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Methanol, 99%&#160;</td>
			<td style="width:284px;">Sigma-Aldrich</td>
			<td style="width:119px;">14262</td>
			<td>dried over molecular sieves</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">N,N-Dicylcohexylcarbodiimide, 99%</td>
			<td style="width:284px;">Sigma-Aldrich</td>
			<td style="width:119px;">D8002</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Dimethyl aminopyridine, 99%</td>
			<td style="width:284px;">Sigma-Aldrich</td>
			<td style="width:119px;">107700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Tert-butylmethylether, 98%</td>
			<td style="width:284px;">Fluka</td>
			<td style="width:119px;">306975</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Polycarbonate membrane</td>
			<td style="width:284px;">Whatman</td>
			<td style="width:119px;"></td>
			<td>Nanopore Track Etched (TE) (1.0 &#956;m, 0.2 &#956;m, 0.1 &#956;m, 50 nm, 30 nm and 15 nm pore diameter; 47 mm or 25 mm membrane diameter)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Caffeine (reagent plus)</td>
			<td style="width:284px;">Sigma-Aldrich</td>
			<td style="width:119px;">C0750&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Franz diffusion cell (12 ml)</td>
			<td style="width:284px;">SES-Analysesysteme</td>
			<td style="width:119px;">6C010015</td>
			<td>15mm unjacheted Franz Cell, 12 ml Receptor volume, Flat ground, clear glass, stirbat and clamp</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">UV-Lamp</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td>UV irradiation (366 nm, 15 W/m2)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">White light lamp</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td>White light irradiation (500 W bulb)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">UV/Vis spectrophotometer</td>
			<td style="width:284px;">Varian 50Bio/50MPR</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:373px;">Polyester membranes</td>
			<td style="width:284px;">Sterlitech</td>
			<td style="width:119px;">PET0225100</td>
			<td>Polyester Membrane Filters, 0.2 &#956;m pore diameter, 25 mmm diameter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Polyvinylidene fluoride membranes</td>
			<td style="width:284px;">Millipore</td>
			<td style="width:119px;"></td>
			<td>PVDF Membranes Durapore (0.22 &#956;m pore diameter; 47 mm membrane diameter)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Argon (99.9995%)</td>
			<td style="width:284px;">Alphagaz</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Dressler Cesar RF Power Generator</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td>Plasma chamber setup</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">MKS Multi Gas Controller 647C</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td>Plasma chamber setup</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">MKS Mass-Flow controllers</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td>Plasma chamber setup</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Vacuubrand RE 2.5 rotary vane vacuum pump</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td>Plasma chamber setup</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Contact angle measurement device Kr&#252;ss G10</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Balances Mettler Toledo AB204-S and Mettler ME30</td>
			<td style="width:284px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation of light-responsive membranes by a combined surface grafting and postmodification process

Afin de modifier la tension de surface de membranes polymères disponibles de voie tranchant commerciaux, une procédure de polymérisation en surface à l&#39;initiative est présentée. La polymérisation à partir de la surface de la membrane est induite par un traitement au plasma de la membrane, suivie d&#39;une réaction de la surface de la membrane avec une solution méthanolique de 2-hydroxyéthyl méthacrylate (HEMA). Une attention particulière est accordée à des paramètres du procédé pour le traitement par plasma avant la polymérisation sur la surface. Par exemple, l&#39;influence du traitement plasma sur différents types de membranes (par exemple de polyester, de polycarbonate, le fluorure de vinylidène) est étudié. Par ailleurs, la stabilité en fonction du temps des membranes à surface greffée est représenté par des mesures d&#39;angle de contact. Lorsque le greffage de poly (méthacrylate de 2-hydroxyéthyle) (PHEMA), de cette manière, la surface peut être encore modifié par estérification du groupement alcool du polymère avec une fonction acide carboxylique de la substance souhaitée.Ces réactions peuvent donc être utilisés pour la fonctionnalisation de la surface de la membrane. Par exemple, la tension de surface de la membrane peut être modifiée ou une fonctionnalité désirée comme la lumière réactivité présentée peut être inséré. Cela est démontré par la réaction avec une unité PHEMA spirobenzopyran fonctionnalisé d&#39;acide carboxylique qui conduit à une membrane sensible à la lumière. Le choix du solvant joue un rôle majeur dans l&#39;étape de modification ultérieure et est discutée plus en détail dans le présent document. Les mesures de perméabilité de ces membranes fonctionnalisées sont effectuées en utilisant une cellule de Franz avec une source de lumière externe. En changeant la longueur d&#39;onde de la lumière du visible à l&#39;UV-gamme, un changement de la perméabilité de solutions aqueuses de caféine est observée.

La vitesse de gravure peut être suivie par pesée de la membrane après les différentes périodes de temps. Comme on peut le voir sur la figure 4, la vitesse de gravure en résulte pour le polyester, le fluorure de vinylidène, et des membranes de polycarbonate d&#39;une vitesse d&#39;attaque linéaire, qui peut être déterminé à partir de la pente de la corrélation linéaire entre le temps de gravure par rapport à la perte de masse. Comme le montre la figure 4, les memb...

Watch this Scientific Journal Video about Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process at JoVE.com

Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process

Un procédé de polymérisation induite par plasma est décrite pour la polymérisation en surface initiée sur des membranes de polymère. En outre modification ultérieure du polymère greffé avec des substances photochromiques est présenté avec un protocole de réalisation de mesures de perméabilité des membranes sensibles à la lumière.

Préparation des membranes sensibles à la lumière par une greffe de surface combiné et processus Modification ultérieure

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is ...

preparation-light-responsive-membranes-combined-surface-grafting

Research

JoVE Journal

Bioengineering

11.7K vues.  Empa, Swiss Federal Laboratories for Materials Science and Technology.  Un procédé de polymérisation induite par plasma est décrite pour la polymérisation en surface initiée sur des membranes de polymère. En outre modification ultérieure du polymère greffé avec des substances photochromiques est présenté avec un protocole de réalisation de mesures de perméabilité des membranes sensibles à la lumière. 

Vidéo: Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process

Measurement of Aggregate Cohesion by Tissue Surface Tensiometry

Rigorous measurement of intercellular binding energy can only be made using methods grounded in thermodynamic principles in systems at equilibrium. We have developed tissue surface tensiometry (TST) specifically to measure the surface free energy of interaction between cells. The biophysical concepts underlying TST have been previously described in detail1,2. The method is based on the observation that mutually cohesive cells, if maintained in shaking culture, will spontaneously assemble into clusters. Over time, these clusters will round up to form spheres. This rounding-up behavior mimics the behavior characteristic of liquid systems. Intercellular binding energy is measured by compressing spherical aggregates between parallel plates in a custom-designed tissue surface tensiometer. The same mathematical equation used to measure the surface tension of a liquid droplet is used to measure surface tension of 3D tissue-like spherical aggregates. The cellular equivalent of liquid surface tension is intercellular binding energy, or more generally, tissue cohesivity. Previous studies from our laboratory have shown that tissue surface tension (1) predicts how two groups of embryonic cells will interact with one another1-5, (2) can strongly influence the ability of tissues to interact with biomaterials6, (3) can be altered not only through direct manipulation of cadherin-based intercellular cohesion7, but also by manipulation of key ECM molecules such as FN8-11 and 4) correlates with invasive potential of lung cancer12, fibrosarcoma13, brain tumor14 and prostate tumor cell lines15. In this article we will describe the apparatus, detail the steps required to generate spheroids, to load the spheroids into the tensiometer chamber, to initiate aggregate compression, and to analyze and validate the tissue surface tension measurements generated.

We describe a method of measuring binding energy, expressible as tissue surface tension, between cells within 3D tissue-like aggregates. Differences in tissue surface tension have been demonstrated to correlate with invasiveness of lung, muscle, and brain tumors, and are fundamental determinants of establishing spatial relationships between different cell types.

Mesure de la cohésion globale par tensiométrie surface du tissu

Rigorous measurement of intercellular binding energy can only be made using methods grounded in thermodynamic principles in systems at equilibrium.  We ...

Recherche

Bio-ingénierie

Self-reporting Scaffolds for 3-Dimensional Cell Culture

Culturing cells in 3D on appropriate scaffolds is thought to better mimic the in vivo microenvironment and increase cell-cell interactions. The resulting 3D cellular construct can often be more relevant to studying the molecular events and cell-cell interactions than similar experiments studied in 2D. To create effective 3D cultures with high cell viability throughout the scaffold the culture conditions such as oxygen and pH need to be carefully controlled as gradients in analyte concentration can exist throughout the 3D construct. Here we describe the methods of preparing biocompatible pH responsive sol-gel nanosensors and their incorporation into poly(lactic-co-glycolic acid) (PLGA) electrospun scaffolds along with their subsequent preparation for the culture of mammalian cells. The pH responsive scaffolds can be used as tools to determine microenvironmental pH within a 3D cellular construct. Furthermore, we detail the delivery of pH responsive nanosensors to the intracellular environment of mammalian cells whose growth was supported by electrospun PLGA scaffolds. The cytoplasmic location of the pH responsive nanosensors can be utilized to monitor intracellular pH (pHi) during ongoing experimentation.

Biocompatible pH responsive sol-gel nanosensors can be incorporated into poly(lactic-co-glycolic acid) (PLGA) electrospun scaffolds. The produced self-reporting scaffolds can be used for in&#160;situ monitoring of microenvironmental conditions whilst culturing cells upon the scaffold. This is beneficial as the 3D cellular construct can be monitored in real-time without disturbing the experiment.

Les échafaudages auto-déclaration pour les 3-Dimensional Culture cellulaire

Culturing cells in 3D on appropriate scaffolds is thought to better mimic the in vivo microenvironment and increase cell-cell interactions. The resulting ...

Generation and Grafting of Tissue-engineered Vessels in a Mouse Model

The construction of vascular conduits is a fundamental strategy for surgical repair of damaged and injured vessels resulting from cardiovascular diseases. The current protocol presents an efficient and reproducible strategy in which functional tissue engineered vessel grafts can be generated using partially induced pluripotent stem cell (PiPSC) from human fibroblasts. We designed a decellularized vessel scaffold bioreactor, which closely mimics the matrix protein structure and blood flow that exists within a native vessel, for seeding of PiPSC-endothelial cells or smooth muscle cells prior to grafting into mice. This approach was demonstrated to be advantageous because immune-deficient mice engrafted with the PiPSC-derived grafts presented with markedly increased survival rate 3 weeks after surgery. This protocol represents a valuable tool for regenerative medicine, tissue engineering and potentially patient-specific cell-therapy in the near future.

Here, we present a protocol to generate tissue engineered vessel grafts that are functional for grafting into mice by double seeding partially induced pluripotent stem cell (PiPSC) - derived smooth muscle cells and PiPSC - derived endothelial cells on a decellularized vessel scaffold bioreactor.

Génération et greffage des navires par ingénierie tissulaire dans un modèle de souris

The construction of vascular conduits is a fundamental strategy for surgical repair of damaged and injured vessels resulting from cardiovascular diseases. ...

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to intrinsic parameters within the process allow a high degree of control over scaffold characteristics including fiber diameter, alignment and porosity. By developing scaffolds with similar dimensions and topographies to organ- or tissue-specific extracellular matrices (ECM), micro-environments representative to those that cells are exposed to in situ can be created. 
The airway bronchiole wall, comprised of three main micro-environments, was selected as a model tissue. Using decellularized airway ECM as a guide, we electrospun the non-degradable polymer, polyethylene terephthalate (PET), by three different protocols to produce three individual electrospun scaffolds optimized for epithelial, fibroblast or smooth muscle cell-culture. Using a commercially available bioreactor system, we stably co-cultured the three cell-types to provide an in vitro model of the airway wall over an extended time period.
This model highlights the potential for such methods being employed in in vitro diagnostic studies investigating important inter-cellular cross-talk mechanisms or assessing novel pharmaceutical targets, by providing a relevant platform to allow the culture of fully differentiated adult cells within 3D, tissue-specific environments.

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Advancements in biomaterial technologies enable the development of three-dimensional multi-cell-type constructs. We have developed electrospinning protocols to produce three individual scaffolds to culture the main structural cells of the airway to provide a 3D in vitro model of the airway bronchiole wall.

Adapter le processus Électrofilage de fournir trois environnements uniques pour un Tri-couches<em&gt; In Vitro</em&gt; Modèle du mur Airway

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to ...

Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

A two-dimensional gas chromatography-time-of-flight mass spectrometry method is described for characterization of the aqueous fraction of bio-crude produced from hydrothermal liquefaction of algae. This protocol can also be employed to analyze the aqueous fraction of liquid products from fast pyrolysis, catalytic fast pyrolysis, catalytic deoxygenation and hydro-treating.

Caractérisation qualitative de la fraction aqueuse de hydrothermale Liquéfaction d&#39;algues Utilisation 2D chromatographie en phase gazeuse avec le temps de vol Spectrométrie de masse

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in ...

Automated Robotic Dispensing Technique for Surface Guidance and Bioprinting of Cells

This manuscript describes the introduction of cell guidance features followed by the direct delivery of cells to these features in a hydrogel bioink using an automated robotic dispensing system. The particular bioink was selected as it allows cells to sediment towards and sense the features. The dispensing system bioprints viable cells in hydrogel bioinks using a backpressure assisted print head. However, by replacing the print head with a sharpened stylus or scalpel, the dispensing system can also be employed to create topographical cues through surface etching. The stylus movement can be programmed in steps of 10 &#181;m in the X, Y and Z directions. The patterned grooves were able to orientate mesenchymal stem cells, influencing them to adopt an elongated morphology in alignment with the grooves&#39; direction. The patterning could be designed using plotting software in straight lines, concentric circles, and sinusoidal waves. In a subsequent procedure, fibroblasts and mesenchymal stem cells were suspended in a 2% gelatin bioink, for bioprinting in a backpressure driven extrusion printhead. The cell bearing bioink was then printed using the same programmed coordinates used for the etching. The bioprinted cells were able to sense and react to the etched features as demonstrated by their elongated orientation along the direction of the etched grooves.

This protocol describes a bioprinting methodology using an automated robotic depositing system that incorporates etched topographical guidance cues with the precision deposition of a cell bearing hydrogel bioink. The printed cells are directly delivered to the etched features and are able to sense and orientate with them.

Automated Robotic Dispensing Technique d&#39;orientation de surface et Bioprinting de cellules

This manuscript describes the introduction of cell guidance features followed by the direct delivery of cells to these features in a hydrogel bioink using ...

Synthesis of Hydrogels with Antifouling Properties As Membranes for Water Purification

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and thus achieving stable water permeability through membranes over time. Here, we report a facile method to prepare hydrogels based on zwitterions for membrane applications. Freestanding films can be prepared from sulfobetaine methacrylate (SBMA) with a crosslinker of poly(ethylene glycol) diacrylate (PEGDA) via photopolymerization. The hydrogels can also be prepared by impregnation into hydrophobic porous supports to enhance the mechanical strength. These films can be characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine the degree of conversion of the (meth)acrylate groups, using goniometers for hydrophilicity and differential scanning calorimetry (DSC) for polymer chain dynamics. We also report protocols to determine the water permeability in dead-end filtration systems and the effect of foulants (bovine serum albumin, BSA) on membrane performance.

This paper reports practical methods to prepare hydrogels in freestanding films and impregnated membranes and to characterize their physical properties, including water transport properties.

Synthèse des hydrogels avec des propriétés antisalissure Membranes pour la purification de l&#39;eau

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause inflammation, fever, hypo- or hypertension, and, in extreme cases, can lead to tissue and organ damage that may become fatal. The amounts of endotoxin in pharmaceutical products, therefore, are strictly regulated. Among the methods available for endotoxin detection and quantification, the Limulus Amoebocyte Lysate (LAL) assay is commonly used worldwide. While any pharmaceutical product can interfere with the LAL assay, nano-formulations represent a particular challenge due to their complexity. The purpose of this paper is to provide a practical guide to researchers inexperienced in estimating endotoxins in engineered nanomaterials and nanoparticle-formulated drugs. Herein, practical recommendations for performing three LAL formats including turbidity, chromogenic and gel-clot assays are discussed. These assays can be used to determine endotoxin contamination in nanotechnology-based drug products, vaccines, and adjuvants.

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

Detection of endotoxins in engineered nanomaterials represents one of the grand challenges in the field of nanomedicine. Here, we present a case study that describes the framework composed of three different LAL formats to estimate potential endotoxin contamination in nanoparticles.

Détection d’endotoxines dans les Nano-formulations utilisant la Limulus Amébocytes Lysate (LAL)

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

Assembly and Characterization of Biomolecular Memristors Consisting of Ion Channel-doped Lipid Membranes

The ability to recreate synaptic functionalities in synthetic circuit elements is essential for neuromorphic computing systems that seek to emulate the cognitive powers of the brain with comparable efficiency and density. To date, silicon-based three-terminal transistors and two-terminal memristors have been widely used in neuromorphic circuits, in large part due to their ability to co-locate information processing and memory. Yet these devices cannot achieve the interconnectivity and complexity of the brain because they are power-hungry, fail to mimic key synaptic functionalities, and suffer from high noise and high switching voltages. To overcome these limitations, we have developed and characterized a biomolecular memristor that mimics the composition, structure, and switching characteristics of biological synapses. Here, we describe the process of assembling and characterizing biomolecular memristors consisting of a 5 nm-thick lipid bilayer formed between lipid-functionalized water droplets in oil and doped with voltage-activated alamethicin peptides. While similar assembly protocols have been used to investigate biophysical properties of droplet-supported lipid membranes and membrane-bound ion channels, this article focuses on key modifications of the droplet interface bilayer method essential for achieving consistent memristor performance. Specifically, we describe the liposome preparation process and the incorporation of alamethicin peptides in lipid bilayer membranes, and the appropriate concentrations of each constituent as well as their impact on the overall response of the memristors. We also detail the characterization process of biomolecular memristors, including measurement and analysis of memristive current-voltage relationships obtained via cyclic voltammetry, as well as short-term plasticity and learning in response to step-wise voltage pulse trains.

Soft, low-power, biomolecular memristors leverage similar composition, structure, and switching mechanisms of bio-synapses. Presented here is a protocol to assemble and characterize biomolecular memristors obtained from insulating lipid bilayers formed between water droplets in oil. The incorporation of voltage-activated alamethicin peptides results in memristive ionic conductance across the membrane.

Assembly and Characterization of Biomolecular Memristors consistant en des Membranes lipidiques dopé au canal ionique

The ability to recreate synaptic functionalities in synthetic circuit elements is essential for neuromorphic computing systems that seek to emulate the ...

Growth of Human and Sheep Corneal Endothelial Cell Layers on Biomaterial Membranes

Corneal endothelial cell cultures have a tendency to undergo epithelial-to-mesenchymal transition (EMT) after loss of cell-to-cell contact. EMT is deleterious for the cells as it reduces their ability to form a mature and functional layer. Here, we present a method for establishing and subculturing human and sheep corneal endothelial cell cultures that minimizes the loss of cell-to-cell contact. Explants of corneal endothelium/Descemet&#39;s membrane are taken from donor corneas and placed into tissue culture under conditions that allow the cells to collectively migrate onto the culture surface. Once a culture has been established, the explants are transferred to fresh plates to initiate new cultures. Dispase II is used to gently lift clumps of cells off tissue culture plates for subculturing. Corneal endothelial cell cultures that have been established using this protocol are suitable for transferring to biomaterial membranes to produce tissue-engineered cell layers for transplantation in animal trials. A custom-made device for supporting biomaterial membranes during tissue culture is described and an example of a tissue-engineered graft composed of a layer of corneal endothelial cells and a layer of corneal stromal cells on either side of a collagen type I membrane is presented.

This protocol describes the critical steps required to establish and grow corneal endothelial cell cultures from explants of human or sheep tissue. A method for subculturing corneal endothelial cells on membranous biomaterials is also presented.