Ce travail de recherche est soutenu dans le cadre du Centre pour le niveau atomique Catalyst conception, un centre de recherche Frontier énergie financé par le Département américain de l&#39;énergie, Bureau de la science, Bureau des sciences fondamentales de l&#39;énergie sous Award Nombre DE-SC0001058 et également soutenu par le Conseil de Regents les subventions du nombre attribution LEQSF (2009-14)-SRTF-MATCH et LEDSF-EPS (2012)-OPT-IN-15. Opérations MRCAT sont pris en charge par le ministère de l&#39;Énergie et des institutions membres de MRCAT. L&#39;utilisation de l&#39;Advanced Photon Source au ANL est soutenu par le Département américain de l&#39;énergie, Bureau de la science, Bureau des sciences fondamentales de l&#39;énergie, sous contrat DE-AC02-06CH11357. Le soutien financier pour JTM a été fourni dans le cadre de l&#39;Institut de Atom efficaces transformations chimiques (IACT), un centre de recherche sur l&#39;énergie Frontier financé par le Département américain de l&#39;énergie, Bureau de la science, Bureau des sciences fondamentales de l&#39;énergie.

Millifluidics SET-UP: Achetez une puce millifluidique (en polymère de téréphtalate de polyester) de Microplumbers microsciences LLC, qui présente des canaux sinueux avec des dimensions de 2 mm (W) x 0,15 mm (H) x 220 mm (L). Utilisation FEP tubes avec des dimensions de 0,25 mm de diamètre interne, de 1/16 à OD, pour la connexion de la puce à la pompe. Utilisez deux pompes différentes pour les deux expériences différentes. Utilisation de la pompe P-pour la première expérience (de nanoparticules de cuivre) et le dispositif millifluidique pour la deuxième expérience (de nanoparticules d&#39;or). Pour minimiser le problème des bulles de gaz dans les canaux, fraîchement préparée de NaBH4 solution a été laissée ouverte au repos pendant ~ 10 à 15 min avant le pompage dans la puce de telle sorte que les bulles de gaz s&#39;échappent de la solution. Cette étape a été suivie pour l&#39;ensemble de nos expériences. Une. Synthèse de l&#39;Ultra-petits clusters cuivre Nano (UCNCs) <ol><li> Produits chimiques nécessaires: Obtenir cuivre (II) Nitrate hydrate, le borohydrure de sodium, de pastilles d&#39;hydroxyde de sodium et d&#39;O-[2 - (3-mercaptopropionylamino)-éthyl]-O&#39;-méthylpolyéthylène glycol (PM = 5000) [MPEG] et utiliser tous les produits chimiques sans autre purification. Utiliser de l&#39;eau nanopure (18,2 MQ-cm) pour l&#39;expérience. </li><li> Utilisation de la pompe P-régulé sous pression d&#39;azote pour l&#39;expérience. Testez les pompes à eau comme solvant à différentes pressions avant l&#39;expérience en corrélation avec les débits correspondants (ml / h). Rincer le réacteur millifluidique et tubes avec de l&#39;eau déminéralisée avant le début de l&#39;expérience. </li><li> Dissoudre 174 mg (0,95 mmol) de cuivre (II) nitrate et 610 mg (0,122 mmol) de O-[2 - (3-mercaptopropionylamino) éthyl]-O&#39;-méthylpolyéthylèneglycol dans 28 ml d&#39;eau nanopure et les conserver dans un flacon pour être connecté avec un canal d&#39;entrée </li><li> Gardez une autre solution de 111 mg (2,93 mmol) de borohydrure de sodium et 102 mg (2,78 mmol) d&#39;hydroxyde de sodium dans 28 ml (pH ~ 13) dans un flacon différent et se connecter avec lal&#39;autre canal d&#39;entrée. </li><li> S&#39;écouler les deux solutions simultanément dans le réacteur millifluidique à différents débits (donnés ci-après) et de recueillir les UCNCs résultant à la sortie, en flacon de verre. Purger la solution avec de l&#39;azote et de le stocker sous azote. </li><li> Faire fonctionner les pompes sous différentes pressions constantes de 50 mbar (6,81 ml / h), 100 mbar (14,31 ml / h), 200 mbar (32,7 ml / h) et 300 mbar (51,4 ml / h) à température ambiante pour la synthèse d&#39; UCNCs à différents débits. </li></ol> Bien que le mode opératoire de synthèse a été démontrée à l&#39;aide du set-up millifluidique avec P-pompe, il peut également être effectuée en utilisant le dispositif tenu à la main millifluidique de Millifluidica. 2. Temps résolu Études cinétiques in situ sur la formation de nanoparticules d&#39;or <ol><li> Produits chimiques nécessaires: Obtenir acide chloroaurique (HAuCl4 3H 2 O). Méso-2 ,3-dimercaptosuccinique (ADMS) et le borohydrure de sodium et #160, et utiliser tous les produits chimiques sans autre purification. Utiliser de l&#39;eau nanopure (18,2 MQ-cm) pour l&#39;expérience. </li><li> Utilisez haute précision, entièrement automatisés, sans pulsation pompes à seringues à l&#39;écoulement des liquides dans la puce. Tester les pompes avec l&#39;eau comme solvant à différents débits avant l&#39;expérience pour optimiser le débit requis. </li><li> Préparer des solutions étalons de (i) HAuCl 4. 3H 2 O (10 mmol, 118,2 mg/30 ml) et (ii) le DMSA (20 mmol, 109,2 mg/30 ml) avec 50 mg d&#39;hydroxyde de sodium (pH 12) en nanopure eau. </li><li> Nourrir les deux solutions à travers deux seringues distinctes dans la puce millifluidique à un débit constant de 10 ml / h à l&#39;aide de la pompe automatique. </li><li> Couple millifluidique la puce à la ligne de faisceau synchrotron au moyen d&#39;un étage de métal qui a accès à un mouvement dans les directions XYZ et de recueillir les données XAS à différentes zones de la puce que les solutions ont été pompés à travers la puce. </li></ol> Alors que le &lt;em&gt; l&#39;analyse in situ a été démontrée en utilisant la procédure de mise en place avec millifluidique P-pompe, il peut également être effectuée en utilisant un dispositif tenu à la main millifluidique. 3. Flux continu d&#39;or Catalyse Cette procédure a été démontrée en utilisant un dispositif tenu à la main millifluidique. <ol><li> Produits chimiques nécessaires: obtenir de l&#39;acide chloroaurique (HAuCl4 3H 2 O de.), Méso-2 ,3-dimercaptosuccinique (ADMS), le borohydrure de sodium, 4-nitrophénol, 4-aminophénol et utilisent tous les produits chimiques sans autre purification. Utiliser de l&#39;eau nanopure (18,2 MQ-cm) pour l&#39;expérience. </li><li> La préparation du catalyseur:. Préparer des solutions standard de HAuCl4 3H 2 O (10 mmol, 118,2 mg/30 ml), ADMS (20 mmol, 109,2 mg/30 ml) et NaBH4 (10 mmol, 11,34 mg/30 ml) dans Nanopure eau. </li><li> Prendre 10 ml de chacune des solutions et HAuCl4 DMSA en deux flacons séparés et e débitlui dans la puce en utilisant le dispositif millifluidique main avec un débit uniforme de 12 ml / h pendant 45 minutes. </li><li> Débit 10 mmol de NaBH4 à l&#39;intérieur de la puce à 12 ml / h de débit pendant 15 min afin de réduire l&#39;Au (I) de Au (0). </li><li> Enfin, laver la puce avec de l&#39;eau nanopure pendant 30 min à la même débit avant d&#39;effectuer les expériences de catalyse. </li><li> réaction de catalyse: effectuer la réaction de conversion chimique (réduction) de 4-nitrophénol (4-NP) dans du 4-aminophénol (4-AP) à l&#39;intérieur du catalyseur d&#39;or (préparé ci-dessus) revêtue canal millifluidique comme donné ci-dessous. </li><li> Mélanger 15 ml de solution de 9 x 10 -5 mol de 4-NP avec 3,3 ml de 0,65 mole de NaBH4 solution pour former des ions nitrophénolate 4-(4-NPI). </li><li> Filtrer la solution résultante sur le catalyseur d&#39;or déposée à l&#39;intérieur de la puce à un débit constant de 5 ml / h pour évaluer l&#39;activité catalytique. Analyser les spectres UV-Vis des produits collectés dans la gamme de longueur d&#39;onde de 250-500 nm pour confirmer la conversion du 4-NP. </li><li> Estimer l&#39;activité catalytique de la réaction par l&#39;obtention de la courbe d&#39;étalonnage de la 4-IPN. Courbe d&#39;étalonnage peut être obtenue en traçant l&#39;intensité de l&#39;absorption observée expérimentalement (I) de 4-IPN à des concentrations standard différentes. Les hauteurs de pics (à 399 nm) pour les courbes Absorption UV-VIS représentent l&#39;intensité d&#39;absorption (I) des valeurs et selon la loi de Lambert Beer, toute variation de la valeur de la hauteur du pic montreraient changement correspondant dans sa concentration. Par conséquent, l&#39;estimation de l&#39;activité catalytique en trouvant la différence dans les concentrations initiale et finale du réactif à partir de la courbe d&#39;étalonnage. Par exemple, si la hauteur de pic est une unité (figure 6), elle correspond à une conversion catalytique de 90% (sur la base de la courbe d&#39;étalonnage). </li></ol>

<ol>
	<li>Song, Y., Hormes, J., Kumar, C. S. S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+Synthesis+of+Nanomaterials.">Microfluidic Synthesis of Nanomaterials.</a> Small. 4 (6), 698-711 (2008).</li><li>Huebner, A., Sharma, S., Srisa-Art, M., Hollfelder, F., Edel, J. B., DeMello, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microdroplets:+a+sea+of+applications.">Microdroplets: a sea of applications.</a> Lab Chip. 8, 1244-1254 (2008).</li><li>Helen, S., Delai, L. C., Rustem, F. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactions+in+Droplets+in+Microfluidic+Channels.">Reactions in Droplets in Microfluidic Channels.</a> Angew. Chem. Int. Ed. 45, 7336-7356 (2006).</li><li>Marre, S., Jensen, K. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+nanostructures+in+microfluidic+systems.">Synthesis of nanostructures in microfluidic systems.</a> Chem. Soc. Rev. 39, 1183-1202 (2010).</li><li>Theberge, A. B., Courtois, F., Schaerli, Y., Fischlechner, M., Abell, C., Hollfelder, F., Huck, W. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microdroplets+in+microfluidics:+an+evolving+platform+for+discoveries+in+chemistry+and+biology.">Microdroplets in microfluidics: an evolving platform for discoveries in chemistry and biology.</a> Angew. Chem. Int. Ed. 49 (34), 5846-5868 (2010).</li><li>Nicolas, L., Flavie, S., Pierre, G., Pascal, P., Annie, C., Bertrand, P., Cindy, H., Patrick, M., Samuel, M., Thomas, D., Cyril, A., Pascale, S., Laurent, P., Christopher, G., Emmanuel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Some+recent+advances+in+the+design+and+the+use+of+miniaturized+droplet-based+continuous+process:+Applications+in+chemistry+and+high-pressure+microflows.">Some recent advances in the design and the use of miniaturized droplet-based continuous process: Applications in chemistry and high-pressure microflows.</a> Lab Chip. 11, 779 (2011).</li><li>Biswas, S., Miller, J. T., Li, Y., Nandakumar, K., Kumar, C. S. S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developing+Millifluidic+Platform+for+Synthesis+of+Ultra-small+Nanoclusters+(UNCs):+Ultra-small+Copper+Nanoclusters+(UCNCs)+as+a+Case+Study.">Developing Millifluidic Platform for Synthesis of Ultra-small Nanoclusters (UNCs): Ultra-small Copper Nanoclusters (UCNCs) as a Case Study.</a> Small. 8 (5), 688-698 (2012).</li><li>Li, Y., Sanampudi, A., Reddy, V. R., Biswas, S., Nandakumar, K., Yamane, D. G., Goettert, J. S., Kumar, C. S. S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size+Evolution+of+Gold+Nanoparticles+in+a+Millifluidic+Reactor.">Size Evolution of Gold Nanoparticles in a Millifluidic Reactor.</a> Phys. Chem. Phys. 13 (1), 177-182 (2012).</li><li>Li, Y., Yamane, D. G., Li, S., Biswas, S., Reddy, R., Goettert, J. S., Nandakumar, K., Kumar, C. S. S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Geometric+Optimization+of+Liquid-Liquid+Slug+Flow+in+a+Flow-focusing+Millifluidic+Device+for+Synthesis+of+Nanomaterials.">Geometric Optimization of Liquid-Liquid Slug Flow in a Flow-focusing Millifluidic Device for Synthesis of Nanomaterials.</a> Chem. Eng. J. 217, 447-459 (2013).</li><li>Zinoveva, S., De Silva, R., Louis, R. D., Datta, P., Kumar, C. S. S. R., Goettert, J., Hormes, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+wet+chemical+synthesis+of+Co+nanoparticles+in+a+microreactor+system:+A+time-resolved+investigation+by+X-ray+absorption+spectroscopy.">The wet chemical synthesis of Co nanoparticles in a microreactor system: A time-resolved investigation by X-ray absorption spectroscopy.</a> Nucl. Instrum. Methods Phys. Res. A. 582, 239-241 (2007).</li><li>Krishna, K. S., Navin, C. V., Biswas, S., Singh, V., Ham, K., Bovenkamp, G. L., Theegala, C. S., Miller, J. T., Spivey, J., Kumar, C. S. S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Millifluidics+for+Time-resolved+Mapping+of+the+Growth+of+Gold+Nanostructures.">Millifluidics for Time-resolved Mapping of the Growth of Gold Nanostructures.</a> J. Am. Chem. Soc. 135 (14), 5450-5456 (2013).</li><li>Kumar, C. S. S. 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> Microfluidic Devices in nanotechnology-Fundamental Concepts. , (2010).</li><li>Kumar, C. S. S. 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> Microfluidic Devices in nanotechnology-Fundamental Concepts. , (2010).</li><li>Meille, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+on+Methods+to+Deposit+Catalysts+on+Structured+Surfaces.">Review on Methods to Deposit Catalysts on Structured Surfaces.</a> Appl. Catal. A Gen. 315, 1-17 (2006).</li><li>Shin, W. C., McDonald, J. A., Zhao, S., Besser, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Etching+Characteristics+of+a+Micromachined+Chemical+Reactor+Using+Inductively+Coupled+Plasma.">Etching Characteristics of a Micromachined Chemical Reactor Using Inductively Coupled Plasma.</a> , p357 (2002).</li><li>Abahmane, L., K&#246;hler, J. M., Gro&#223;, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gold-nanoparticle-catalyzed+synthesis+of+propargylamines:+the+traditional+A3-multicomponent+reaction+performed+as+a+two-step+flow+process.">Gold-nanoparticle-catalyzed synthesis of propargylamines: the traditional A3-multicomponent reaction performed as a two-step flow process.</a> Chem. Eur. J. 17, 3005-3010 (2011).</li><li>Abahmane, L., Knauer, A., Ritter, U., K&#246;hler, J. M., Gro&#223;, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneous+Catalyzed+Pyridine+Synthesis+using+Montmorillionite+and+Nanoparticle-Impregnated+Alumina+in+a+Continuous+Micro+Flow+System.">Heterogeneous Catalyzed Pyridine Synthesis using Montmorillionite and Nanoparticle-Impregnated Alumina in a Continuous Micro Flow System.</a> Chem. Eng. Technol. 32, 1799-1805 (2009).</li><li>Abahmane, L., Knauer, A., K&#246;hler, J. M., Gro&#223;, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+polypyridine+derivatives+using+alumina+supported+gold+nanoparticles+under+micro+continuous+flow+conditions.">Synthesis of polypyridine derivatives using alumina supported gold nanoparticles under micro continuous flow conditions.</a> Chem. Eng. J. 167, 519-526 (2011).</li><li>Negishi, Y., Tsukuda, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-Pot+Preparation+of+Subnanometer-Sized+Gold+Clusters+via+Reduction+and+Stabilization+by+meso-2,3-Dimercaptosuccinic+Acid.">One-Pot Preparation of Subnanometer-Sized Gold Clusters via Reduction and Stabilization by meso-2,3-Dimercaptosuccinic Acid.</a> J. Am. Chem. Soc. 125, 4046-4047 (2003).</li><li>Abou-Hassan, A., Sandre, O., Cabuil, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidics+in+Inorganic+Chemistry.">Microfluidics in Inorganic Chemistry.</a> Angew. Chem. Int. Ed. 49, 6268-6286 (2010).</li><li>Jiang, D., Walter, M., Dai, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gold+Sulfide+Nanoclusters:+A+Unique+Core-In-Cage+Structure.">Gold Sulfide Nanoclusters: A Unique Core-In-Cage Structure.</a> Chem. Eur. J. 16, 4999-5003 (2010).</li><li>Kuroda, K., Ishida, T., Haruta, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+of+4-nitrophenol+to+4-aminophenol+over+Au+nanoparticles+deposited+on+PMMA.">Reduction of 4-nitrophenol to 4-aminophenol over Au nanoparticles deposited on PMMA.</a> J. Mol. Catal. A Chem. 298, 7-11 (2009).</li><li>Navin, C. V., Krishna, K. S., Theegala, C. S., Kumar, C. S. S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lab-on-a-chip+devices+for+gold+nanoparticle+synthesis+and+their+role+as+a+catalyst+support+for+continuous+flow+catalysis.">Lab-on-a-chip devices for gold nanoparticle synthesis and their role as a catalyst support for continuous flow catalysis.</a> Nanotech. Rev. , (2013).</li><li>Shahbazali, E., Hessel, V., No&#235;l, T., Wang, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metallic+nanoparticles+made+in+flow+and+their+catalytic+applications+in+organic+synthesis.">Metallic nanoparticles made in flow and their catalytic applications in organic synthesis.</a> Nanotech. Rev. , (2013).</li></ol>

Tous les auteurs, à l&#39;exception CSSR Kumar déclarer qu&#39;ils n&#39;ont pas d&#39;intérêts financiers concurrents. C. SSR Kumar est le fondateur de la société Millifluidica LLC.

Les UCNCs ont été formés par la réaction de réduction du nitrate de cuivre avec du borohydrure de sodium en présence du polymère de coiffage agent de O-[2 - (3-Mercaptopropionylamino)-éthyl]-O&#39;-méthylpolyéthylène glycol (PM = 5000) [MPEG]. La réaction a été effectuée dans le réacteur de puce millifluidique à différents débits tels que 6,8 ml / h, 14,3 ml / h, 32,7 ml / h, et 51,4 ml / h pour étudier l&#39;effet des débits sur les UCNCs formés. Les temps de séjour respectifs pour les débits ci...

Lab-on-a-chip (LOC) des dispositifs pour la synthèse chimique ont démontré un avantage significatif en termes d&#39;augmentation de la masse et le transfert de chaleur, contrôle de réaction supérieure, un débit élevé et plus sûr l&#39;environnement de fonctionnement 1. Ces dispositifs peuvent être classés en copeaux à base fluidique et dispositifs fluidiques de nonchip base. Parmi les fluidique à puce, la microfluidique est bien étudié et un sujet bien couvert dans la littérature 2-5. Systèmes LOC base Nonchip utilisent des réacteurs tubulaires 6. Classiquement, les systèmes microfluidiques sont utilisés pour le contrôle et la manipulation des fluides qui sont géométriquement contraints à l&#39;échelle submillimétrique précis. Nous avons récemment introduit le concept de millifluidics à puce, qui peuvent être utilisés pour la manipulation des fluides dans les canaux à l&#39;échelle millimétrique (soit la largeur ou la profondeur ou les deux canaux sont au moins un millimètre) 7-9. En outre, les puces millifluidique sont relativement faciles à fabriquer WHIle offrant un contrôle similaire sur les débits et la manipulation de réactifs. Ces puces peuvent aussi être utilisés à des débits plus élevés, créant de plus petites durées de séjour, ce qui, en offrant la possibilité de mise à l&#39;échelle de la synthèse contrôlée des nanoparticules avec une distribution étroite de la taille. A titre d&#39;exemple, nous avons récemment démontré la synthèse de l&#39;ultra-petites nanoparticules de cuivre et leur caractérisé par spectroscopie d&#39;absorption des rayons X in situ ainsi que TEM. Aptitude à obtenir des petits temps de séjour à l&#39;intérieur de canaux millifluidique en combinaison avec l&#39;utilisation du MPEG, ce qui est très efficace bidentate pégylé agent stabilisant pour la formation de colloïdes stables de nanoparticules de cuivre 7. En plus de la synthèse de produits chimiques et des nanomatériaux, les millifluidics pourraient offrir, en raison du volume plus élevé et la concentration à la surface de la sonde, une plate-forme de synthèse qui est plus générale et efficace pour des études cinétiques résolues en temps et également AchieVes meilleur rapport signal bruit de systèmes microfluidiques 7,10. Nous montrons l&#39;utilisation de la puce millifluidique comme un exemple pour les temps résolu analyse de la croissance de nanostructures d&#39;or de la solution à l&#39;aide in situ XAS avec une résolution aussi faible que 5 ms 11 de temps. En outre, la majorité des micro réacteurs développés à ce jour pour les applications de catalyse sont basées sur 12,13 de silicium. Leur fabrication cher en plus petits volumes générés les rend impropres à la fabrication à grande échelle. Les deux méthodes générales pour revêtir les canaux avec nanocatalyseurs - chimiques et physiques, souvent appelés procédés de revêtement de silicium, sont actuellement en vogue 14,15. En plus de micro fabrication coûteuse, l&#39;obstruction des canaux rend micro réacteur catalyse peut être impropre à la fabrication à grande échelle. Bien que microréacteurs ont été utilisés pour la catalyse hétérogène dans les micro continues accréditives processus EARLIer 16 à 18, la possibilité de contrôler la dimension et la morphologie des catalyseurs nanostructurés d&#39;or incorporés à l&#39;intérieur des canaux d&#39;écoulement continu n&#39;a jamais été explorées avant. Nous avons récemment développé une technologie pour le revêtement des canaux millifluidique avec Au-catalyseurs, après avoir contrôlé nano morphologie et les dimensions (Figure 5) 11, pour la réalisation de la catalyse de réactions chimiques importants industriellement. A titre d&#39;exemple, nous avons démontré la conversion de 4-nitrophénol dans le 4-aminophénol catalysée par l&#39;or nanostructuré revêtu dans les canaux millifluidique. Considérant que d&#39;une seule puce de réacteur millifluidique peut produire des débits de 50-60 ml / h, 7 à haut débit et la synthèse contrôlée de produits chimiques est possible soit par le fonctionnement en flux continu ou traitement parallèle. Afin de capitaliser sur les possibilités les millifluidics offrent, avec quelques exemples décrits ci-dessus, nous démontrons également une interface convivialedispositif millifluidique qui est portable et a les tous les composants nécessaires tels que les puces millifluidique, collecteurs, régulateurs de débit, les pompes et les connexions électriques intégrés. Un tel dispositif millifluidique, comme le montre la figure 7, est désormais disponible auprès de la société Millifluidica LLC ( <a href="http://www.millifluidica.com" target="_blank">www.millifluidica.com</a> ). Le manuscrit fournit également des protocoles utilisant le dispositif millifluidique à main, tel que décrit ci-dessous, pour la synthèse contrôlée des nanomatériaux, l&#39;analyse en temps résolu de mécanismes de réaction et la catalyse en flux continu.

<table border="1">
	<tbody>
		<tr>
			<td>Copper (II) nitrate hydrate</td>
			<td>Sigma-Aldrich</td>
			<td>13778-31-9</td>
			<td>99.999% pure</td>
		</tr>
		<tr>
			<td>O-[2-(3-mercaptopropionylamino)ethyl]-O&#8242;-methylpolyethylene glycol</td>
			<td>Sigma-Aldrich</td>
			<td>401916-61-8&#160;</td>
			<td>MW=5,000</td>
		</tr>
		<tr>
			<td>HAuCl4.3H2O (Chloroauric acid)</td>
			<td>Sigma-Aldrich</td>
			<td>27988-77-8&#160;</td>
			<td>99.999% pure</td>
		</tr>
		<tr>
			<td>meso-2,3-dimercaptosuccinic acid (DMSA)</td>
			<td>Sigma-Aldrich</td>
			<td>304-55-2</td>
			<td>~98% pure</td>
		</tr>
		<tr>
			<td>4-Nitrophenol</td>
			<td>Sigma-Aldrich</td>
			<td>100-02-7&#160;</td>
			<td>spectrophotometric grade</td>
		</tr>
		<tr>
			<td>4-Aminophenol</td>
			<td>Sigma-Aldrich</td>
			<td>123-30-8&#160;</td>
			<td>&#62;99% pure (HPLC grade)</td>
		</tr>
		<tr>
			<td>Sodium borohydride</td>
			<td>Sigma-Aldrich</td>
			<td>16940-66-2&#160;</td>
			<td>98% pure</td>
		</tr>
		<tr>
			<td>Sodium hydroxide pellets</td>
			<td>Sigma-Aldrich</td>
			<td>1310-73-2&#160;</td>
			<td>99.99% pure</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>[header]</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>EQUIPMENT</td>
		</tr>
		<tr>
			<td>Millifluidic Chips</td>
			<td>Microplumbers Microsciences LLC</td>
			<td>SDC-01</td>
			<td>Made from polyester terephthalate polymer</td>
		</tr>
		<tr>
			<td>Pressure Pump</td>
			<td>Mitos P-Pump, Dolomite</td>
			<td>3200016</td>
			<td></td>
		</tr>
		<tr>
			<td>Automated Syringe Pump</td>
			<td>Cetoni Automation and Microsystems, GmbH</td>
			<td></td>
			<td>Syringe pump neMESYS</td>
		</tr>
		<tr>
			<td>UV-3600 UV-VIS-NIR Spectrophotometer</td>
			<td>Shimadzu</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hand-held Millifluidic Device</td>
			<td>Millifluidica</td>
			<td>SCMD-1008</td>
			<td>Figure 7</td>
		</tr>
	</tbody>
</table>

millifluidics for chemical synthesis and time-resolved mechanistic studies

Procédures utilisant des dispositifs millifluidique pour la synthèse chimique et études mécanistiques résolue en temps sont décrits en prenant trois exemples. Dans le premier, la synthèse de l&#39;ultra-petites nanoparticules de cuivre est décrite. Le deuxième exemple fournit leur utilité pour l&#39;étude en temps résolu cinétique des réactions chimiques en analysant la formation des nanoparticules d&#39;or en utilisant la spectroscopie d&#39;absorption des rayons X in situ. Le dernier exemple démontre la catalyse de flux continu de réactions à l&#39;intérieur canal millifluidique revêtus de catalyseur nanostructuré.

Bien dispersés et nanoclusters de cuivre de taille uniforme avec une distribution de tailles étroite ont été obtenus en utilisant la configuration de la puce millifluidique (Fig. 1a). Les différents débits utilisés pour la synthèse n&#39;ont pas eu d&#39;effet significatif sur la taille des clusters. Cependant, avec l&#39;augmentation de la vitesse d&#39;écoulement, on observe une amélioration observable dans le rétrécissement de la distribution de la taille. UCNCs avec une meilleure distribution de tailles ...

Watch this Scientific Journal Video about Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies at JoVE.com

Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies

Dispositifs millifluidique sont utilisés pour la synthèse contrôlée des nanomatériaux, l&#39;analyse en temps résolu de mécanismes de réaction et la catalyse en flux continu.

Millifluidics de synthèse chimique et résolue en temps des études mécanistes

Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the ...

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11.1K vues.  Louisiana State University.  Dispositifs millifluidique sont utilisés pour la synthèse contrôlée des nanomatériaux, l'analyse en temps résolu de mécanismes de réaction et la catalyse en flux continu. 

Vidéo: Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies

Combinatorial Synthesis of and High-throughput Protein Release from Polymer Film and Nanoparticle Libraries

Polyanhydrides are a class of biomaterials with excellent biocompatibility and drug delivery capabilities. While they have been studied extensively with conventional one-sample-at-a-time synthesis techniques, a more recent high-throughput approach has been developed enabling the synthesis and testing of large libraries of polyanhydrides1. This will facilitate more efficient optimization and design process of these biomaterials for drug and vaccine delivery applications. The method in this work describes the combinatorial synthesis of biodegradable polyanhydride film and nanoparticle libraries and the high-throughput detection of protein release from these libraries. In this robotically operated method (Figure 1), linear actuators and syringe pumps are controlled by LabVIEW, which enables a hands-free automated protocol, eliminating user error. Furthermore, this method enables the rapid fabrication of micro-scale polymer libraries, reducing the batch size while resulting in the creation of multivariant polymer systems. This combinatorial approach to polymer synthesis facilitates the synthesis of up to 15 different polymers in an equivalent amount of time it would take to synthesize one polymer conventionally. In addition, the combinatorial polymer library can be fabricated into blank or protein-loaded geometries including films or nanoparticles upon dissolution of the polymer library in a solvent and precipitation into a non-solvent (for nanoparticles) or by vacuum drying (for films). Upon loading a fluorochrome-conjugated protein into the polymer libraries, protein release kinetics can be assessed at high-throughput using a fluorescence-based detection method (Figures 2 and 3) as described previously1. This combinatorial platform has been validated with conventional methods2 and the polyanhydride film and nanoparticle libraries have been characterized with 1H NMR and FTIR. The libraries have been screened for protein release kinetics, stability and antigenicity; in vitro cellular toxicity, cytokine production, surface marker expression, adhesion, proliferation and differentiation; and in vivo biodistribution and mucoadhesion1-11. The combinatorial method developed herein enables high-throughput polymer synthesis and fabrication of protein-loaded nanoparticle and film libraries, which can, in turn, be screened in vitro and in vivo for optimization of biomaterial performance.

This method describes the combinatorial synthesis of biodegradable polyanhydride film and nanoparticle libraries and the high-throughput detection of protein release from these libraries.

Synthèse combinatoire des protéines et de décharge à haut débit à partir du film polymère et bibliothèques nanoparticules

Polyanhydrides are a class of biomaterials with excellent biocompatibility and drug delivery capabilities. While they have been studied extensively with ...

Recherche

Bio-ingénierie

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

À haut débit la synthèse des glucides et fonctionnalisation de nanoparticules polyanhydride

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

Microfabrication of Nanoporous Gold Patterns for Cell-material Interaction Studies

Nanostructured materials with feature sizes in tens of nanometers have enhanced the performance of several technologies, including fuel cells, biosensors, biomedical device coatings, and drug delivery tools. Nanoporous gold (np-Au), produced by a nano-scale self-assembly process, is a relatively new material that exhibits large effective surface area, high electrical conductivity, and catalytic activity. These properties have made np-Au an attractive material to scientific community. Most studies on np-Au employ macro-scale specimens and focus on fundamental science of the material and its catalytic and sensor applications. The macro-scale specimens limit np-Au's potential in miniaturized systems, including biomedical devices. In order to address these issues, we initially describe two different methods to micropattern np-Au thin films on rigid substrates. The first method employs manually-produced stencil masks for creating millimeter-scale np-Au patterns, while the second method uses lift-off photolithography to pattern sub-millimeter-scale patterns. As the np-Au thin films are obtained by sputter-deposition process, they are compatible with conventional microfabrication techniques, thereby amenable to facile integration into microsystems. These systems include electrically-addressable biosensor platforms that benefit from high effective surface area, electrical conductivity, and gold-thiol-based surface bioconjugation. We describe cell culture, immunostaining, and image processing techniques to quantify np-Au's interaction with mammalian cells, which is an important performance parameter for some biosensors. We expect that the techniques illustrated here will assist the integration of np-Au in platforms at various length-scales and in numerous applications, including biosensors, energy storage systems, and catalysts.

We report on techniques to micropattern nanoporous gold thin films via stencil printing and photolithography, as well as methods to culture cells on the microfabricated patterns. In addition, we describe image analysis methods to characterize morphology of the material and the cultured cells using scanning electron and fluorescence microscopy techniques.

Microfabrication de Patterns d&#39;or nanoporeux d&#39;études sur l&#39;interaction cellule-matériau

Nanostructured materials with feature sizes in tens of nanometers have enhanced the performance of several technologies, including fuel cells, biosensors, ...

Synthesis of an Intein-mediated Artificial Protein Hydrogel

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of this hydrogel are two protein block-copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. A highly hydrophilic random coil is inserted into one of the block-copolymers for water retention. Mixing of the two protein block copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit with crosslinkers at either end that rapidly self-assembles into a hydrogel. This hydrogel is very stable under both acidic and basic conditions, at temperatures up to 50 &#176;C, and in organic solvents. The hydrogel rapidly reforms after shear-induced rupture. Incorporation of a &#34;docking station peptide&#34; into the hydrogel building block enables convenient incorporation of &#34;docking protein&#34;-tagged target proteins. The hydrogel is compatible with tissue culture growth media, supports the diffusion of 20 kDa molecules, and enables the immobilization of bioactive globular proteins. The application of the intein-mediated protein hydrogel as an organic-solvent-compatible biocatalyst was demonstrated by encapsulating the horseradish peroxidase enzyme and corroborating its activity.

We present the synthesis of a split-intein-mediated protein hydrogel. The building blocks of this hydrogel are two protein copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. Mixing of the two protein copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit that self-assembles into a hydrogel. This hydrogel is highly pH- and temperature-stable, compatible with organic solvents, and easily incorporates functional globular proteins.

Synthèse d&#39;une protéine artificielle induite par une intéine Hydrogel

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of ...

Synthesis of Keratin-based Nanofiber for Biomedical Engineering

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of these porous nanofibers is of great interest due to their unique physiochemical properties. Here we elaborate on the fabrication of keratin containing poly (&#949;-caprolactone) (PCL) nanofibers (i.e., PCL/keratin composite fiber). Water soluble keratin was first extracted from human hair and mixed with PCL in different ratios. The blended solution of PCL/keratin was transformed into nanofibrous membranes using a laboratory designed electrospinning set up. Fiber morphology and mechanical properties of the obtained nanofiber were observed and measured using scanning electron microscopy and tensile tester. Furthermore, degradability and chemical properties of the nanofiber were studied by FTIR. SEM images showed uniform surface morphology for PCL/keratin fibers of different compositions. These PCL/keratin fibers also showed excellent mechanical properties such as Young&#39;s modulus and failure point. Fibroblast cells were able to attach and proliferate thus proving good cell viability. Based on the characteristics discussed above, we can strongly argue that the blended nanofibers of natural and synthetic polymers can represent an excellent development of composite materials that can be used for different biomedical applications.

Electrospun nanofibers have a high surface area to weight ratio, excellent mechanical integrity, and support cell growth and proliferation. These nanofibers have a wide range of biomedical applications. Here we fabricate keratin/ PCL nanofibers, using the electrospinning technique, and characterize the fibers for possible applications in tissue engineering.

Synthèse de nanofibres à base de kératine de génie biomédical

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of ...

The Synthesis of RGD-functionalized Hydrogels as a Tool for Therapeutic Applications

The use of polymers as biomaterials has provided significant advantages in therapeutic applications. In particular, the possibility to modify and functionalize polymer chains with compounds that are able to improve biocompatibility, mechanical properties, or cell viability allows the design of novel materials to meet new challenges in the biomedical field. With the polymer functionalization strategies, click chemistry is a powerful tool to improve cell-compatibility and drug delivery properties of polymeric devices. Similarly, the fundamental need of biomedicine to use sterile tools to avoid potential adverse-side effects, such as toxicity or contamination of the biological environment, gives rise to increasing interest in the microwave-assisted strategy.
The combination of click chemistry and the microwave-assisted method is suitable to produce biocompatible hydrogels with desired functionalities and improved performances in biomedical applications. This work aims to synthesize RGD-functionalized hydrogels. RGD (arginylglycylaspartic acid) is a tripeptide that can mimic cell adhesion proteins and bind to cell-surface receptors, creating a hospitable microenvironment for cells within the 3D polymeric network of the hydrogels. RGD functionalization occurs through Huisgen 1,3-dipolar cycloaddition. Some PAA carboxyl groups are modified with an alkyne moiety, whereas RGD is functionalized with azido acid as the terminal residue of the peptide sequence. Finally, both products are used in a copper catalyzed click reaction to permanently link the peptide to PAA. This modified polymer is used with carbomer, agarose and polyethylene glycol (PEG) to synthesize a hydrogel matrix. The 3D structure is formed due to an esterification reaction involving carboxyl groups from PAA and carbomer and hydroxyl groups from agarose and PEG through microwave-assisted polycondensation. The efficiency of the gelation mechanism ensures a high degree of RGD functionalization. In addition, the procedure to load therapeutic compounds or biological tools within this functionalized network is very simple and reproducible.

We present a protocol for the synthesis of RGD-functionalized hydrogels as devices for cell and drug delivery. The procedure involves copper catalyzed alkyne-azide cycloaddition (CuAAC) between alkyne-modified polyacrylic acid (PAA) and a RGD-azide derivative. The hydrogels are formed using microwave-assisted polycondensation and their physicochemical properties are investigated.

La Synthèse des RGD-fonctionnalisé hydrogels comme un outil pour les applications thérapeutiques

The use of polymers as biomaterials has provided significant advantages in therapeutic applications. In particular, the possibility to modify and ...

Polydimethylsiloxane-polycarbonate Microfluidic Devices for Cell Migration Studies Under Perpendicular Chemical and Oxygen Gradients

This paper reports a microfluidic device made of polydimethylsiloxane (PDMS) with an embedded polycarbonate (PC) thin film to study cell migration under combinations of chemical and oxygen gradients. Both chemical and oxygen gradients can greatly affect cell migration in vivo; however, due to technical limitations, very little research has been performed to investigate their effects in vitro. The device developed in this research takes advantage of a series of serpentine-shaped channels to generate the desired chemical gradients and exploits a spatially confined chemical reaction method for oxygen gradient generation. The directions of the chemical and oxygen gradients are perpendicular to each other to enable straightforward migration result interpretation. In order to efficiently generate the oxygen gradients with minimal chemical consumption, the embedded PC thin film is utilized as a gas diffusion barrier. The developed microfluidic device can be actuated by syringe pumps and placed into a conventional cell incubator during cell migration experiments to allow for setup simplification and optimized cell culture conditions. In cell experiments, we used the device to study migrations of adenocarcinomic human alveolar basal epithelial cells, A549, under combinations of chemokine (stromal cell-derived factor, SDF-1&#945;) and oxygen gradients. The experimental results show that the device can stably generate perpendicular chemokine and oxygen gradients and is compatible with cells. The migration study results indicate that oxygen gradients may play an essential role in guiding cell migration, and cellular behavior under combinations of gradients cannot be predicted from those under single gradients. The device provides a powerful and practical tool for researchers to study interactions between chemical and oxygen gradients in cell culture, which can promote better cell migration studies in more in vivo-like microenvironments.

The control of chemical and oxygen gradients is essential for cell cultures. This paper reports a polydimethylsiloxane-polycarbonate (PDMS-PC) microfluidic device capable of reliably generating combinations of chemical and oxygen gradients for cell migration studies, which can be practically utilized in biological labs without sophisticated instrumentation.

Polydiméthylsiloxane-polycarbonate dispositifs microfluidiques pour cellulaire Migration Studies Sous Perpendiculaire chimique et Dégradés d&#39;oxygène

This paper reports a microfluidic device made of polydimethylsiloxane (PDMS) with an embedded polycarbonate (PC) thin film to study cell migration under ...

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 ...

Ammonia Synthesis at Low Pressure

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called &#34;stranded,&#34; because it is only available far from population centers where it can be directly used.
In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 &#176;C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia can be synthesized at low pressure by using a conventional catalyst and an ammonia selective absorbent.

Synthèse de l’ammoniac à basse pression

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in ...

Synthesis of Functionalized 10-nm Polymer-coated Gold Particles for Endothelium Targeting and Drug Delivery

Gold nanoparticles (AuNPs) have been used extensively in medical research due to their size, biocompatibility, and modifiable surface. Specific targeting and drug delivery are some of the applications of these AuNPs, but endothelial extracellular matrices&#39; defensive properties hamper particle uptake. To address this issue, we describe a synthesis method for ultrasmall gold nanoparticles to improve vascular delivery, with customizable functional groups and polymer lengths for further adjustments. The protocol yields 2.5 nm AuNPs that are capped with tetrakis(hydroxymethyl)phosphonium chloride (THPC). The replacement of THPC with hetero-functional polyethylene glycol (PEG) on the surface of the AuNP increases the hydrodynamic radius to 10.5 nm while providing various functional groups on the surface. The last part of the protocol includes an optional addition of a fluorophore to allow the AuNPs to be visualized under fluorescence to track nanoparticle uptake. Dialysis and lyophilization were used to purify and isolate the AuNPs. These fluorescent nanoparticles can be visualized in both in vitro and in vivo experiments due to the biocompatible PEG coating and fluorescent probes. Additionally, the size range of these nanoparticles render them an ideal candidate for probing the glycocalyx without disrupting normal vasculature function, which may lead to improved delivery and therapeutics.

We describe a method of synthesizing biocompatible 10-nm gold nanoparticles, functionalized by coating poly-ethylene glycol onto the surface. These particles can be used in vitro and in vivo for delivering therapeutics to nanoscale cellular and extracellular spaces that are difficult to access with conventional nanoparticle sizes.

Synthèse des fonctionnalisées 10 nm revêtement polymère des particules d’or pour le ciblage de l’endothélium et MEDICAMENTS

Gold nanoparticles (AuNPs) have been used extensively in medical research due to their size, biocompatibility, and modifiable surface. Specific targeting ...