Questo lavoro di ricerca è supportata come parte del Centro per livello atomico Catalyst Design, Frontier Centro di ricerca energetica finanziata dal Dipartimento dell&#39;Energia degli Stati Uniti, Office of Science, Ufficio di Scienze di base dell&#39;energia sotto Award Numero DE-SC0001058 e sostenuto anche dal Consiglio di Regents sotto sovvenzioni numero aggiudicazione LEQSF (2009-14)-EFRC-Match e LEDSF-EPS (2012)-OPT-IN-15. Operazioni MRCAT sono supportate dal Dipartimento dell&#39;Energia e delle istituzioni aderenti MRCAT. L&#39;uso del Advanced Photon Source di ANL è sostenuta dal Dipartimento dell&#39;Energia degli Stati Uniti, Office of Science, Ufficio di Scienze di base dell&#39;energia, nell&#39;ambito del contratto n ° DE-AC02-06CH11357. Il sostegno finanziario per JTM è stato fornito come parte dell&#39;Istituto per Atom-efficienti trasformazioni chimiche (IACT), un centro di ricerca energetica Frontier finanziato dal Dipartimento dell&#39;Energia degli Stati Uniti, Office of Science, Ufficio delle Scienze di base dell&#39;energia.

Millifluidics set-up: Acquistare un chip millifluidic (in poliestere polimero tereftalato) dal Microplumbers Microsciences LLC, che ha canali a serpentina con dimensioni di 2 mm (W) x 0,15 millimetri (H) x 220 mm (L). Utilizzare FEP Tubing con dimensioni 0,25 mm ID, 1/16 in OD, per collegare il chip alla pompa. Utilizzare due pompe diverse per i due diversi esperimenti. Con P-Pompa per il primo esperimento (nanoparticelle di rame) e il dispositivo millifluidic per il secondo esperimento (nanoparticelle di oro). Per ridurre al minimo il problema di bolle di gas all&#39;interno dei canali, preparata di fresco NaBH4 soluzione viene lasciata aperta riposare per ~ 10-15 minuti prima del pompaggio nel chip in modo che le bolle di gas sfuggono dalla soluzione. Questa fase è stata seguita per tutti i nostri esperimenti. 1. Sintesi di Ultra-piccole di rame Nano Clusters (UCNCs) <ol><li> Prodotti chimici richiesti: Ottenere rame (II) nitraTE idrato, boroidruro di sodio, idrossido di sodio e pellets O-[2 - (3-mercaptopropionylamino) etil]-O&#39;-methylpolyethylene glicole (MW = 5.000) [MPEG] e utilizzare tutti i prodotti chimici senza ulteriore purificazione. Utilizzare acqua Nanopure (18,2 mW cm) per l&#39;esperimento. </li><li> Con P-pompa regolata sotto pressione di azoto per l&#39;esperimento. Testare le pompe con l&#39;acqua come solvente a diverse pressioni prima dell&#39;esperimento di correlare con i flussi corrispondenti (ml / h). Sciacquare il reattore millifluidic e tubi con acqua deionizzata prima dell&#39;inizio dell&#39;esperimento. </li><li> Sciogliere 174 mg (0,95 mmol) di rame (II) nitrato e 610 mg (0,122 mmol) di O-[2 - (3-mercaptopropionylamino) etil]-O&#39;-methylpolyethylene glicole in 28 ml di acqua Nanopure e tenerli in un flaconcino essere collegato con un canale di ingresso </li><li> Mantenere un&#39;altra soluzione di 111 mg (2,93 mmol) di boroidruro di sodio e 102 mg (2,78 mmol) di idrossido di sodio in 28 ml (pH ~ 13) in una fiala diversa e collegarlo con l&#39;altro canale di ingresso. </li><li> Flusso entrambe le soluzioni contemporaneamente all&#39;interno del reattore millifluidic a diverse portate (riportate di seguito) e raccogliere le UCNCs risultanti in uscita in flaconcino di vetro. Spurgare la soluzione con azoto e conservarlo sotto azoto. </li><li> Azionare le pompe sotto diverse pressioni costanti di 50 mbar (6.81 ml / hr), 100 mbar (14.31 ml / hr), 200 mbar (32,7 ml / h) e 300 mbar (51,4 ml / hr) a temperatura ambiente per la sintesi di UCNCs a differenti portate. </li></ol> Mentre la procedura di sintesi è stata dimostrata usando l&#39;millifluidic set-up con P-pompa, può anche essere effettuata utilizzando il dispositivo millifluidic portatile da Millifluidica. 2. Tempo risolto in situ Studi cinetici su Gold nanoparticelle Formazione <ol><li> Prodotti chimici richiesti: Ottenere acido chloroauric (HAuCl4 3H 2 O). Meso-2 ,3-dimercaptosuccinico (DMSA) e sodio boroidruro &amp; #160, e utilizzare tutte le sostanze chimiche senza ulteriore purificazione. Utilizzare acqua Nanopure (18,2 mW cm) per l&#39;esperimento. </li><li> Utilizzare alta precisione, completamente automatizzate, pulsazioni gratuito pompe siringa a scorrere i liquidi all&#39;interno del chip. Testare le pompe con l&#39;acqua come solvente a diverse portate prima dell&#39;esperimento per ottimizzare la portata necessaria. </li><li> Preparare soluzioni standard di (i) HAuCl4. 3H 2 O (10 mmol, 118,2 mg/30 ml) e (ii) DMSA (20 mmol, 109,2 mg/30 ml) con 50 mg di idrossido di sodio (pH 12) in Nanopure acqua. </li><li> Alimentare i due soluzioni attraverso due siringhe diverse nel chip millifluidic costantemente ad una portata di 10 ml / h utilizzando la pompa automatizzato. </li><li> Coppia il chip millifluidic alla linea di fascio sincrotrone utilizzando una fase metallica che ha accesso al movimento in direzioni XYZ e raccogliere i dati XAS in diverse zone del chip come le soluzioni sono stati pompati attraverso il chip. </li></ol> Mentre il &lt;em&gt; analisi in situ procedimento è stata dimostrata usando l&#39;millifluidic set-up con P-pompa, può anche essere eseguita utilizzando un dispositivo millifluidic portatile. 3. Flusso continuo Oro Catalysis Questa procedura è stata dimostrata utilizzando un dispositivo millifluidic portatile. <ol><li> Chimica richieste: Ottenere acido chloroauric (HAuCl4 3H 2 O.), Meso-2 ,3-dimercaptosuccinico (DMSA), boroidruro di sodio, 4-nitrofenolo, 4 aminophenol e utilizzare tutte le sostanze chimiche senza ulteriore purificazione. Utilizzare acqua Nanopure (18,2 mW cm) per l&#39;esperimento. </li><li> Preparazione del catalizzatore:. Preparare le soluzioni standard di HAuCl4 3H 2 O (10 mmol, 118,2 mg/30 ml), DMSA (20 mmol, 109,2 mg/30 ml) e NaBH4 (10 mmol, 11,34 mg/30 ml) in Nanopure acqua. </li><li> Prendere 10 ml ciascuna di HAuCl4 e soluzioni DMSA in due flaconcini separati e il flusso them all&#39;interno del chip utilizzando il dispositivo millifluidic portatile con una portata uniforme di 12 ml / h per 45 min. </li><li> Di flusso 10 mmol NaBH4 all&#39;interno del chip a 12 ml / hr portata per 15 min per ridurre l&#39;Au (I) Au (0). </li><li> Infine, lavare il chip con acqua Nanopure per 30 minuti alla stessa portata prima di condurre gli esperimenti di catalisi. </li><li> Reazione Catalisi: Eseguire la reazione di conversione chimica (riduzione) del 4-nitrofenolo (4-NP) in 4 aminofenolo (4-AP) entro il catalizzatore oro (preparata in precedenza) rivestito canale millifluidic come indicato di seguito. </li><li> Mescolare 15 ml di soluzione di 9 x 10 -5 moli di 4-NP con 3.3 ml di 0,65 mol NaBH 4 soluzione per formare ioni 4 nitrophenolate (4-NPI). </li><li> Far passare la soluzione risultante sul catalizzatore oro depositato entro chip alla portata costante di 5 ml / hr per valutare l&#39;attività catalitica. Analizzare gli spettri UV-Vis dei prodotti raccolti nell&#39;intervallo di lunghezza d&#39;onda di 250-500 nm per confermare la conversione di 4-NP. </li><li> Valutare l&#39;attività catalitica della reazione ottenendo la curva di taratura di 4-NPI. Curva di calibrazione può essere acquisita riportando l&#39;intensità di assorbimento osservato sperimentalmente (I) di 4-NPI a differenti concentrazioni standard. Le altezze dei picchi (a 399 nm) per le curve di assorbimento UV-Vis rappresentano l&#39;intensità di assorbimento valori (I) e secondo la legge di Beer Lambert, qualsiasi variazione del valore di altezza di picco mostrerebbero corrispondente variazione nella sua concentrazione. Pertanto, valutare l&#39;attività catalitica trovando la differenza di concentrazioni iniziali e finali del reagente dalla curva di calibrazione. Ad esempio, se l&#39;altezza è di 1 unità (Figura 6) che corrisponde ad una conversione catalitica del 90% (in base al diagramma di taratura). </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>

Tutti gli autori ad eccezione CSSR Kumar dichiarano di non avere interessi finanziari in competizione. C. SSR Kumar è il fondatore della società Millifluidica LLC.

Le UCNCs sono formate dalla reazione di riduzione di nitrato di rame con boroidruro di sodio in presenza di agente polimerico tappatura O-[2 - (3-Mercaptopropionylamino) etil]-O&#39;-methylpolyethylene glicole (MW = 5.000) [MPEG]. La reazione è stata effettuata all&#39;interno del reattore di chip millifluidic a diverse portate come 6,8 ml / h, 14,3 ml / h, 32,7 ml / h, e 51,4 ml / h per studiare l&#39;effetto delle portate sui UCNCs formate. I rispettivi tempi di permanenza per i flussi di cui sopra sono 47.49, 24.44,...

Dispositivi Lab-on-a-chip (LOC) per sintesi chimica hanno dimostrato un significativo vantaggio in termini di aumento di massa e trasferimento di calore, controllo di reazione superiore, alta produttività e ambiente operativo più sicuro 1. Questi dispositivi possono essere classificati in fluidica di chip basati e dispositivi fluidici nonchip based. Tra i fluidica basati su chip, microfluidica è ben studiata e un argomento ben trattato nella letteratura 2-5. Sistemi basati LOC Nonchip utilizzano reattori tubolari 6. Convenzionalmente, sistemi microfluidici sono utilizzati per un controllo preciso e manipolazione di fluidi che sono geometricamente vincolati a scala submillimetrica. Abbiamo recentemente introdotto il concetto di millifluidics basati su chip, che possono essere utilizzati per la manipolazione di fluidi in canali in scala millimetrica (larghezza o profondità o entrambi i canali sono almeno un millimetro) 7-9. Inoltre, i chip millifluidic sono relativamente facili da fabbricare whiLe offrendo controllo analogo su portate e la manipolazione dei reagenti. Questi chip possono essere usati anche a portate più elevate, creando tempi di permanenza più piccole, così, che offre la possibilità di scale-up di sintesi controllata di nanoparticelle con distribuzione granulometrica ristretta. Come esempio, abbiamo recentemente dimostrato la sintesi di ultra-piccole nanocluster rame e caratterizzato mediante spettroscopia di assorbimento di raggi X situ e TEM. Possibilità di ottenere piccoli tempi di permanenza all&#39;interno dei canali millifluidic in combinazione con l&#39;uso di MPEG, che è molto efficiente bidentato PEGylated agente stabilizzante per la formazione di colloidi stabili di nanocluster rame 7. Oltre alla sintesi di prodotti chimici e nanomateriali, i millifluidics potrebbe offrire, grazie alla maggiore volume e la concentrazione nella zona di sonda, una piattaforma sintetico che è più generalizzato ed efficiente per studi cinetici risolta nel tempo e anche ragVES migliore rapporto segnale-rumore rispetto ai sistemi microfluidici 7,10. Mostriamo l&#39;uso di chip di millifluidic come esempio per tempo risolto analisi della crescita di nanostrutture oro da soluzione utilizzando in situ XAS con una risoluzione temporale di soli 5 ​​msec 11. Inoltre, la maggioranza dei micro reattori sviluppati fino ad oggi per applicazioni di catalisi si riferiscono al 12,13 silicio. Loro fabbricazione costosa oltre a piccoli volumi generati li rende inadatti per la produzione su larga scala. I due metodi generali per rivestire i canali con nanocatalysts - chimico-fisiche, spesso definito come le procedure di rivestimento di silicio, sono attualmente in voga 14,15. Oltre a costoso micro fabbricazione, intasamento dei canali rende micro reattore catalisi può essere adatta per la produzione su larga scala. Sebbene microreattori sono state utilizzate per la catalisi eterogenea in micro continuo flusso attraverso processi earlier 16-18, la capacità di controllare la dimensione e morfologia dei catalizzatori nanostrutturati oro incorporati nei canali di flusso continuo è stato mai esplorate prima. Abbiamo recentemente sviluppato una tecnologia per rivestire i canali millifluidic con Au catalizzatori, dopo aver controllato nano morfologia e dimensioni (Figura 5) 11, per la realizzazione di catalisi di reazioni chimiche industrialmente importanti. Come esempio abbiamo dimostrato conversione di 4-nitrofenolo in 4-amminofenolo catalizzata da oro nanostrutturato rivestite all&#39;interno dei canali millifluidic. Considerando che un singolo chip reattore millifluidic può produrre portate di 50-60 ml / hr, 7 ad alta produttività e sintesi controllata di sostanze chimiche è possibile sia attraverso il funzionamento di flusso continuo o elaborazione parallela. Al fine di sfruttare le possibilità dei millifluidics offrono, con alcuni esempi descritti come sopra, anche noi dimostriamo un user-friendlydispositivo millifluidic che è portatile e ha i tutti i componenti necessari quali chip millifluidic, collettori, regolatori di flusso, pompe e collegamenti elettrici integrati. Tale dispositivo millifluidic, come mostrato nella figura 7, è ora disponibile presso la società Millifluidica LLC ( <a href="http://www.millifluidica.com" target="_blank">www.millifluidica.com</a> ). Il manoscritto fornisce anche i protocolli usando il dispositivo millifluidic portatile, come descritto di seguito, per la sintesi controllata di nanomateriali, analisi risolta nel tempo dei meccanismi di reazione e catalisi flusso continuo.

<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

Procedure che utilizzano dispositivi millifluidic per la sintesi chimica e studi meccanicistici risolte nel tempo sono descritte prendendo tre esempi. Nel primo, la sintesi di ultra-piccole nanocluster rame è descritto. Il secondo esempio fornisce loro utilità per indagare risolte nel tempo cinetica delle reazioni chimiche analizzando formazione di nanoparticelle d&#39;oro utilizzando nella spettroscopia di assorbimento di raggi X situ. L&#39;ultimo esempio viene illustrato catalisi flusso continuo di reazioni all&#39;interno del canale millifluidic rivestiti con catalizzatore nanostrutturato.

Bene dispersi e nanocluster uniformi di rame dimensioni, con una distribuzione di dimensione ristretta sono stati ottenuti utilizzando la configurazione di chip millifluidic (Fig. 1a). Le diverse portate utilizzati per la sintesi non hanno un effetto significativo sulla dimensione dei cluster. Tuttavia, con aumento della portata, c&#39;è un miglioramento osservabile nel restringimento della distribuzione dimensionale. UCNCs con una migliore distribuzione della dimensione ristretta sono stati ottenuti a portata di 32,7 ...

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

Dispositivi Millifluidic sono utilizzati per la sintesi controllata dei nanomateriali, analisi risolta nel tempo dei meccanismi di reazione e catalisi flusso continuo.

Millifluidics per sintesi chimica e risolte nel tempo meccanicistici Studies

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

millifluidics-for-chemical-synthesis-time-resolved-mechanistic

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11.1K Views.  Louisiana State University.  Dispositivi Millifluidic sono utilizzati per la sintesi controllata dei nanomateriali, analisi risolta nel tempo dei meccanismi di reazione e catalisi flusso continuo. 

Video: 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.

Sintesi combinatoria di e High-throughput di rilascio di proteine ​​da film polimerico e Biblioteche nanoparticelle

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

Ricerca

Bioingegneria

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.

High-throughput sintesi dei carboidrati e funzionalizzazione di nanoparticelle polianidride

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 di Patterns Oro nanoporosi per Cell-materiali Interaction Studies

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.

Sintesi di una proteina artificiale mediata da inteina 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.

Sintesi di nanofibre cheratina-based per Ingegneria Biomedica

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 sintesi di RGD-funzionalizzati idrogeli come strumento per applicazioni terapeutiche

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.

Polidimetilsilossano-policarbonato dispositivi microfluidici per Cell Migration Studies Sotto perpendicolare chimica e gradienti di ossigeno

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.

Sintesi di idrogel con proprietà antivegetative come membrane per la purificazione dell&#39;acqua

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.

Sintesi dell'ammoniaca a bassa pressione

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.

Sintesi di particelle d'oro rivestite di polimeri 10-nm funzionalizzate per il Targeting di endotelio e Drug Delivery

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