Questo lavoro è stato sostenuto da Western Kentucky University Ogden College of Science and Engineering, incluso il supporto interno del Dipartimento di Chimica e dall&#39;Ufficio di Ricerca (PACR 13-8032). L&#39;assistenza del dottor John Andersland presso l&#39;impianto di WKU Microscopia (immagini SEM) e Professore Associato Yan Cao dell&#39;Istituto WKU per Combustion Scienza e Ingegneria (analisi BET) è stata fondamentale per lo svolgimento di questo lavoro.

1. Preparazione di emulsioni <ol><li> Contenuti emulsione <ol><li> Messa una quantità appropriata di sale per la produzione di 10 ml di soluzione 0,03-M. Per platino (IV) misura cloruro 0,101 g, per lo zinco (II) cloruro (ZnCl 2) misura 0,032 g, e cloruro di sodio (NaCl) misura 0,018 g. </li><li> In provette singoli, dissolvere ogni sale in 10 ml di acqua deionizzata. Mettere da parte per un uso successivo. </li><li> Utilizzare a 20 ml, flaconcino di vetro richiudibile per i contenuti durante tutta la procedura. Tarare un equilibrio per la fiala di vetro. </li><li> Pesare polidimetilsilossano vinil-denuncia da parte lentamente versando sopra un bastoncino per mescolare e nel flacone di vetro appoggiata sulla scala azzerato. Pesare 1,02 g (equivalente a 1.080 ml). NOTA: L&#39;alta viscosità di questo polimero rende impraticabile pipettamento. </li><li> Pipettare 1,02 ml di n-eptano flaconcino. Aggiungere 2 gocce di tensioattivo non ionico (sorbitan monooleato) alla fiala. Pipettare 0,3 ml di soluzione salina e 0,45 ml di acqua demineralizzata al flacone. </li><li> Sigillare la fiala di vetro avvitando il coperchio ermeticamente. Agitare energicamente per 60 secondi per avviare l&#39;emulsione prima di iniziare ultrasuoni. </li></ol></li><li> Costruzione di Bagnomaria Sonicator Apparatus <ol><li> Riempire sonicatore con acqua fino alla linea di riempimento minimo. Aggiungere 250 ml di acqua di rubinetto in un bicchiere da 400 ml. Riempire il becher da 400 ml con ghiaccio così che il livello dell&#39;acqua è solo sul bordo. </li><li> Inserire questa coppa all&#39;interno del sonicatore bagnomaria. Controllare il fill-line sul sonicatore, regolando se necessario. Posizionare un anello supporto direttamente sul sonicatore bagnomaria. </li><li> Utilizzando due anello basamento morsetti, posizionarli in modo che un braccio viene estesa, perpendicolare alla gradinata e un altro è esteso verso il bagno di acqua in modo che sia rivolta verso il basso nel contenitore riempito con acqua ghiacciata. Fissare un&#39;altra fascetta all&#39;anello stand con un termometro nel becher da 400 ml in modo che la temperatura può essere monitorato durante sonicazione. </li></ol></li><li> Emulsificazione Procedura <ol><li> Posizionare la fiala-emulsione contenente in modo che sia completamente immerso nel becher da 400 ml, fissandolo nel morsetto sporgente verso il basso nel becher. </li><li> Assicurarsi che la fiala di vetro contenente la miscela PDMS non tocca le pareti del becher per eliminare il calore per attrito. </li><li> Accendere il sonicatore e impostare il tempo di ultrasuoni per 7 minuti. Poiché l&#39;emulsione è molto sensibile al calore, assicurare che la temperatura all&#39;interno del recipiente è compreso tra 0 e 5 ° C durante sonicazione. Avviare sonicazione quando la temperatura all&#39;interno del bicchiere è desiderabile. </li><li> Dopo 7 minuti di sonicazione, togliere la fiala e scuotere delicatamente / turbolenza per 1 min, tenendo la parte superiore del flaconcino per eliminare eventuali grumi che possono formarsi in emulsione. </li><li> Eliminare il contenuto del becher. Riempire con 250 ml di acqua e ghiaccio per aggiungere il riempimento da 1 cm nella parte superiore della coppa. </li><li> Posizionare la fiala nel morsetto. Immergere sotto l&#39;acqua ghiacciata per risommaree sonicazione per 7 minuti. </li><li> Ripetere i punti 1.3.3 a 1.3.6 per un totale di otto periodi sonicazione, 7 min, o fino a quando la sonicazione appare omogeneo e senza grumi sono presenti. Conservare a temperatura ambiente. NOTA: L&#39;emulsione deve essere stabile per diversi giorni, ma può essere recuperato mediante sonicazione come sopra in 7-min intervalli finché non appare omogeneo. Conservare a temperatura ambiente. </li></ol></li></ol> 2. La reticolazione <ol><li> Configurazione per l&#39;aggiunta di trietossisilano / Tensioattivo Soluzione <ol><li> Pipettare 5.4 ml trietossisilano in una provetta. Mettere in un rack provetta sotto il cofano per un uso successivo. </li><li> Riempire un bicchiere da 400 ml con acqua ghiacciata e posizionarlo sotto il cofano. Accanto al posto becher da 400 ml basamento un anello con un morsetto attaccato, estesa direttamente sull&#39;apertura del bicchiere. Questo sarà il bagno di ghiaccio per l&#39;aggiunta di trietossisilano. </li><li> Posizionare una piastra calda sull&#39;altro lato del supporto ad anello. Riempire un bicchiere di 800 ml con circa 700 ml diacqua di rubinetto. Mettere sul piatto caldo. </li><li> Accendere la piastra riscaldante e mantenere una temperatura di 75 a 85 ° C all&#39;interno del becher da 800 ml. Fissare un morsetto con un termometro per il supporto ad anello in modo che la temperatura dell&#39;acqua all&#39;interno del becher da 800 ml può essere monitorato. </li><li> Produrre la soluzione tensioattivo sciogliendo 0,5 g di sodio dodecilsolfato a 375 ml di acqua (4,62 mM). Aggiungere circa 10 ml di soluzione di tensioattivo a una provetta vuota pulita. </li><li> Fissare un&#39;altra fascetta all&#39;anello stare sotto il cofano con la provetta tensioattivo fissate in modo che il suo livello del liquido è al di sotto della superficie dell&#39;acqua all&#39;interno del becher da 800 ml. Lasciare 10 minuti per il raggiungimento dell&#39;equilibrio termico. </li><li> Bagnare un pezzo di carta da filtro e posizionarlo nella parte superiore di un piccolo imbuto. Posizionare il gambo dell&#39;imbuto all&#39;interno di una beuta da 250 ml e il recipiente sotto il cofano. </li></ol></li><li> Aggiunta di trietossisilano <ol><li> Posizionare il flaconcino dell&#39;emulsione nel morsetto sopra il becco acqua ghiacciataer all&#39;interno della cappa. Posizionare la miscela PDMS nel morsetto in modo che il contenuto della fiala sono sotto la superficie dell&#39;acqua. L&#39;aggiunta di triethoxysilane provoca una reazione esotermica, quindi l&#39;emulsione deve essere mantenuto freddo per mantenere la sua struttura. </li><li> Togliere il coperchio dalla fiala di vetro per evitare accumulo di gas. </li><li> Versare lentamente il triethoxysilane provetta contenente nella fiala di vetro in un flusso continuo per un periodo di circa 10 secondi (circa 0,5 ml / sec). ATTENZIONE: L&#39;aggiunta di triethoxysilane avvia una reazione esotermica e il rilascio di caustica acido cloridrico (HCl) gas. La fiala diventa estremamente caldo e un gas tossico evolverà dalla miscela. Non mescolare il contenuto, mentre l&#39;aggiunta del trietossisilano. </li><li> Dopo aver aggiunto completamente trietossisilano, mescolare delicatamente il contenuto con una bacchetta di vetro scalpore, mentre indossa un guanto protettivo termico. Attendere per 2 minuti o fino a quando si ferma di gas in continua evoluzione dal flaconcino. </li><li> Follcausa reticolazione, non vi è alcuna separazione di fase visibile nel campione. Se sono presenti grumi, sigillare la fiala e agitare rigorosamente per 20 secondi mentre si tiene la fiala dal coperchio. </li></ol></li><li> Produzione Bead <ol><li> Utilizzare un ambiente pulito, Pasteur pipetta di vetro per disegnare l&#39;emulsione reticolato dal flaconcino di vetro. Aggiungere l&#39;emulsione reticolato goccia a goccia alla soluzione di tensioattivo (che dovrebbe essere mantenuta tra 75 e 85 ° C) nella provetta prendendo il minor tempo possibile tra gocce. </li><li> 30 sec a 1 min dopo l&#39;aggiunta dell&#39;emulsione, la soluzione tensioattivo inizierà lentamente ad evolversi gas come solidi cominciano a formarsi all&#39;interno della provetta. </li><li> Mentre indossa guanti protettivi calore, prendere la provetta dalla pinza e versare l&#39;intero contenuto nel dispositivo di filtrazione sotto il cofano. Filtro per 5 min. Rimuovere la carta da filtro dal filtro. </li><li> Trasferire i solidi filtrati su un vetro da orologio e perline separate per O / N asciugatura sotto la hood. Pulizia delle perline può essere rinviata a tempo indeterminato. Conservare le sfere a RT essiccato in una fiala di vetro sigillato fino al momento, e pulire immediatamente prima dell&#39;uso. </li></ol></li><li> Bead Pulizia <ol><li> Creare un altro apparato di filtrazione sotto il cofano e posizionare i talloni secchi all&#39;interno dell&#39;imbuto sopra la carta da filtro. </li><li> Utilizzare una bottiglia di lavaggio di plastica riempita con acqua demineralizzata per lavare le perline delicatamente, li muoversi leggermente al fine di garantire tutte le perle vengono risciacquati. </li><li> Lasciate che le perline asciugare per 1 ora mettendoli su un vetro da orologio sotto il cofano. Utilizzare una bottiglia di lavaggio riempita con esani per sciacquare le perline con lo stesso metodo per il risciacquo con acqua. </li><li> Mettere le perline su un vetro da orologio. Posizionare il vetro d&#39;orologio e le perline sotto il cofano a secco. </li><li> Dopo le perle sono completamente asciutti, metterli in una piccola fiala di vetro sigillato e conservare a temperatura ambiente per un utilizzo futuro. </li></ol></li><li> Montaggio delle Perline per impostazioni di analisi SEM e SEM <ol><li> Posizionare una striscia di donastro conduttivo di carbonio uble lati sopra l&#39;stub su cui saranno montate le perline. Utilizzando le forbici, tagliare intorno lo stub per garantire che non si blocca a nastro sopra i bordi. </li><li> Posizionare un pezzo di carta da filtro sotto lo stub su una superficie piana. Rimuovere lo strato superiore dal nastro in modo che la parte inferiore adesiva è esposta. </li><li> Versare delicatamente le perle sulla stub. Alcune perle che si attacchi al nastro, ma la maggior parte si rimbalzano e atterrare sulla carta da filtro. Versare questi indietro nel flaconcino se sono rimasti sulla carta da filtro. Ripetere se necessario, lavare eventuali perline (secondo 2.4.2 a 2.4.5), che diventano contaminati. </li><li> Per garantire le perle sono sicuro sul stub, utilizzare una siringa a bulbo e leggermente soffiare molto da vicino alla superficie stub. Versare più perline sopra lo stub se solo pochi aderito al nastro. Assicurarsi che tutti i cordoni siano sicuri prima di mettere il mozzicone nella camera SEM ed evacuare esso. </li><li> Una volta che i campioni sono stati montati correttamente sono ora pronti a subire SEM analeYsis 15. Raccogliere le immagini in modalità LOW VAC a 15 keV per ottimizzare la risoluzione delle caratteristiche superficiali del tallone. </li></ol></li></ol>

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The authors have nothing to disclose.

Le perle prodotte usando questo protocollo (e regolando la concentrazione di elettroliti e l&#39;identità) sono fondamentalmente diversi da quelli prodotti con una emulsione di bassa forza ionica, come visto dal confronto della figura 1A alle altre immagini SEM di Figura 1. La relazione iniziale usati PtCl 4 con l&#39;intenzione di catalizzare ulteriormente la polimerizzazione reticolazione all&#39;interfaccia acquosa-alifatico 14.</sup...

Polydimethylsiloxane (PDMS) is one of the most widely used silicone compounds. Its biocompatibility has led to widespread use in implant and other biomedical engineering structures1,2. It is trivially cross-linked into elastic structures using an organosilyl compound (such as triethoxysilane), a simple and reliable procedure which has made it useful for cast polymer applications where some flexibility is required3. Once cross-linked, PDMS is largely inert, particularly in biological conditions, and is therefore useful for a variety of food and medical applications4,5. Ease of casting, chemical inertness, and hydrophobicity have made it a natural choice for microfluidic devices6,7. Its affinity for non-halogenated, non-polar organic compounds has made it a popular stationary phase in separations chemistry8-10. 
Recently, microbubble fabrications have been used to generate porous beads for use as catalyst structural substrates or in chemical separations11,12. In both applications, ideal materials will have a maximized surface-area-to-volume (SAV) ratio for best efficiency. In a microbubble fabrication process, microstructuring of materials is typically accomplished by isolating the polymer in aliphatic &#8220;microbubbles&#8221; by emulsification in an aqueous continuous phase. The initial report of microporous PDMS beads produced them by mechanical emulsification of two phases (aliphatic and aqueous)13. The stock PDMS liquid (and its cross-linking agent) is dissolved into the aliphatic phase, which is structured into microscopic beads by being forced to cavitate within the (continuous) aqueous phase. The emulsification is stabilized by the addition of a non-ionic surfactant. When the emulsion is added dropwise to a heated bath, solid beads form by agglomeration of the microbubbles into clusters of tiny spheres of cross-linked PDMS. Our goal in this protocol is to modify this procedure to develop beads with an inverted porosity to improve the SAV ratio of the material.
As reported previously, control of the beads can be directed to some extent by the aliphatic:aqueous ratios in the emulsion. However, we have reported recently that addition of platinum(IV) chloride (PtCl4) inverts the porosity: materials are formed in which the PDMS is riddled with concave pores14. This indicates that the aqueous layer cavitates inside the aliphatic one, despite having similar aliphatic:aqueous ratios to those published in the original work13. The primary advantage of our method is that this concave porosity should naturally result in an increased SAV ratio, and thus, improved efficiency for analytical chemistry applications. While we are continuing to explore the specific effects of the addition of the platinum compound, we show here that the same effect can be accomplished using any aqueously soluble ionic compound, though perhaps to a reduced extent. Because our techniques also differ in some key aspects from what has been previously reported, we present our protocols here as a video to encourage others to extend our methods. Most notably, we use a common bath sonicator of the type used to clean glassware or other equipment, rather than the (considerably more expensive) probe sonicator often used in microbubble fabrication. This adjusted approach to the microbubble fabrication procedure could potentially be extended for the production of large quantities of bulk materials as well, creating porous sheets or slabs which could have applications for biomedical devices, aerospace and automotive industry, or substrates for chemical catalysis. Users seeking to generate high-SAV-ratio, microstructured materials using other similar polymers for such analyses may find that our protocols can be extended to any polymer for which the microbubble emulsion technique can be applied.

<table border="0">
	<tbody>
		<tr>
			<td>Poly(dimethylsiloxane), vinyl terminated</td>
			<td>Sigma-Aldrich</td>
			<td>68083-19-2</td>
			<td></td>
		</tr>
		<tr>
			<td>n-Heptane</td>
			<td>Sigma-Aldrich</td>
			<td>142-82-5</td>
			<td>Flammable</td>
		</tr>
		<tr>
			<td>Triethoxysilane</td>
			<td>Sigma-Aldrich</td>
			<td>998-30-1</td>
			<td>Flammable, Accutely Toxic</td>
		</tr>
		<tr>
			<td>Sorbitan Monoleate (Span-80)</td>
			<td>Fluker</td>
			<td>1338-43-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Platinum (IV) Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>13454-96-1</td>
			<td>Accutely Toxic</td>
		</tr>
		<tr>
			<td>Zinc (II) Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>7646-85-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>7647-14-5</td>
			<td></td>
		</tr>
		<tr>
			<td>2.8L Water Bath Sonicator</td>
			<td>VWR</td>
			<td>97043-964</td>
			<td></td>
		</tr>
	</tbody>
</table>

microbubble fabrication of concave-porosity pdms beads

Microbubble fabrication (by use of a fine emulsion) provides a means of increasing the surface-area-to-volume (SAV) ratio of polymer materials, which is particularly useful for separations applications. Porous polydimethylsiloxane (PDMS) beads can be produced by heat-curing such an emulsion, allowing the interface between the aqueous and aliphatic phases to mold the morphology of the polymer. In the procedures described here, both polymer and crosslinker (triethoxysilane) are sonicated together in a cold-bath sonicator. Following a period of cross-linking, emulsions are added dropwise to a hot surfactant solution, allowing the aqueous phase of the emulsion to separate, and forming porous polymer beads. We demonstrate that this method can be tuned, and the SAV ratio optimized, by adjusting the electrolyte content of the aqueous phase in the emulsion. Beads produced in this way are imaged with scanning electron microscopy, and representative SAV ratios are determined using Brunauer&#8211;Emmett&#8211;Teller (BET) analysis. Considerable variability with the electrolyte identity is observed, but the general trend is consistent: there is a maximum in SAV obtained at a specific concentration, after which porosity decreases markedly.

Immagini rappresentative SEM di perline derivanti da emulsioni con condizioni elettroliti diverse sono mostrati in figura 1. La figura 1A mostra una perlina simili a quelli ottenuti da Dufaud, et al. 13, prodotta con le nostre procedure, senza l&#39;aggiunta di qualsiasi elettrolita. Perline mostrati nella Figura 1B-D, con conseguente diverse morfologie per ogni ione metallico. Per tutte le immagini mostrate, 300 ml di soluzioni elettrolitiche 0,03-M...

Watch this Scientific Journal Video about Microbubble Fabrication of Concave-porosity PDMS Beads at JoVE.com

Microbubble Fabrication of Concave-porosity PDMS Beads

Procedures used to generate microstructured concave-porosity polydimethylsiloxane beads are presented. Effects of electrolyte concentration and identity within the aqueous phase are particularly emphasized.

Fabbricazione microbolle di Perline PDMS Concavo-porosità

Microbubble fabrication (by use of a fine emulsion) provides a means of increasing the surface-area-to-volume (SAV) ratio of polymer materials, which is ...

microbubble-fabrication-of-concave-porosity-pdms-beads

Research

JoVE Journal

Chemistry

8.2K Views.  Western Kentucky University. Procedures used to generate microstructured concave-porosity polydimethylsiloxane beads are presented. Effects of electrolyte concentration and identity within the aqueous phase are particularly emphasized. 

Video: Microbubble Fabrication of Concave-porosity PDMS Beads

Fabrication of Large-area Free-standing Ultrathin Polymer Films

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films. Typically, ultrathin films are prepared using either sacrificial layers, which may damage the film or affect its mechanical properties, or they are made on freshly cleaved mica, a substrate that is difficult to scale. Further, the size of ultrathin film is typically limited to a few square millimeters. In this method, we modify a surface with a polyelectrolyte that alters the strength of adhesion between polymer and deposition substrate. The polyelectrolyte can be shown to remain on the wafer using spectroscopy, and a treated wafer can be used to produce multiple films, indicating that at best minimal amounts of the polyelectrolyte are added to the film. The process has thus far been shown to be limited in scalability only by the size of the coating equipment, and is expected to be readily scalable to industrial processes. In this study, the protocol for making the solutions, preparing the deposition surface, and producing the films is described.

We describe a method for the fabrication of large-area (up to 13 cm diameter) and ultrathin (as thin as 8 nm) polymer films. Instead of using a sacrificial interlayer to delaminate the film from its substrate, we use a self-limiting surface treatment suitable for arbitrarily large areas.

Fabbricazione di ampia superficie Free-standing ultrasottili film polimerici

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films.  Typically, ultrathin films are prepared ...

Ricerca

Chimica

Flow-pattern Guided Fabrication of High-density Barcode Antibody Microarray

Antibody microarray as a well-developed technology is currently challenged by a few other established or emerging high-throughput technologies. In this report, we renovate the antibody microarray technology by using a novel approach for manufacturing and by introducing new features. The fabrication of our high-density antibody microarray is accomplished through perpendicularly oriented flow-patterning of single stranded DNAs and subsequent conversion mediated by DNA-antibody conjugates. This protocol outlines the critical steps in flow-patterning DNA, producing and purifying DNA-antibody conjugates, and assessing the quality of the fabricated microarray. The uniformity and sensitivity are comparable with conventional microarrays, while our microarray fabrication does not require the assistance of an array printer and can be performed in most research laboratories. The other major advantage is that the size of our microarray units is 10 times smaller than that of printed arrays, offering the unique capability of analyzing functional proteins from single cells when interfacing with generic microchip designs. This barcode technology can be widely employed in biomarker detection, cell signaling studies, tissue engineering, and a variety of clinical applications.

This protocol outlines the fabrication of a large-scale, multiplexed two-dimensional DNA or antibody array, with potential applications in cell signaling studies and biomarker detection.

Flow-modello Fabrication guidata della alta densità di codici a barre anticorpo Microarray

Antibody microarray as a well-developed technology is currently challenged by a few other established or emerging high-throughput technologies. In this ...

Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability

We have recently developed a simple, reusable and coupled whole-cell biocatalytic system with the capability of cofactor regeneration and biocatalyst immobilization for improved production yield and sustained synthesis. Described herewith is the experimental procedure for the development of such a system consisting of two E. coli strains that express functionally complementary enzymes. Together, these two enzymes can function co-operatively to mediate the regeneration of expensive cofactors for improving the product yield of the bioreaction. In addition, the method of synthesizing an immobilized form of the coupled biocatalytic system by encapsulation of whole cells in calcium alginate beads is reported. As an example, we present the improved biosynthesis of L-xylulose from L-arabinitol by coupling E. coli cells expressing the enzymes L-arabinitol dehydrogenase or NADH oxidase. Under optimal conditions and using an initial concentration of 150 mM L-arabinitol, the maximal L-xylulose yield reached 96%, which is higher than those reported in the literature. The immobilized form of the coupled whole-cell biocatalysts demonstrated good operational stability, maintaining 65% of the yield obtained in the first cycle after 7 cycles of successive re-use, while the free cell system almost completely lost the catalytic activity. Therefore, the methods reported here provides two strategies that could help improve the industrial production of L-xylulose, as well as other value-added compounds requiring the use of cofactors in general.

Presented is the protocol for co-immobilizing whole-cell biocatalysts for cofactor regeneration and improved reusability, using the production of L-xylulose as an example. The cofactor regeneration is achieved by coupling two Escherichia coli strains expressing functionally complementary enzymes; the whole-cell biocatalyst immobilization is achieved by cell encapsulation in calcium alginate beads.

L&#39;immobilizzazione di Multi-biocatalizzatori in perline alginato per cofattore Rigenerazione e migliorata Riusabilità

We have recently developed a simple, reusable and coupled whole-cell biocatalytic system with the capability of cofactor regeneration and biocatalyst ...

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to achieve device efficiencies exceeding other thin film device technologies. Yet, large variations in device efficiency and basic physical properties are reported. This is due to unintentional variations during film processing, which have not been sufficiently investigated so far. We therefore conducted an extensive study of the morphology and electronic structure of a large number of CH3NH3PbI3 perovskite where we show how the preparation method as well as the mixing ratio of educts methylammonium iodide and lead(II) iodide impact properties like film formation, crystal structure, density of states, energy levels, and ultimately the solar cell performance.

We present an extensive study on the effects of different fabrication methods for organic/inorganic perovskite thin films by comparing crystal structures, density of states, energy levels, and ultimately the solar cell performance.

Influenza di ibridi metodi di fabbricazione perovskite sulla formazione cinematografica, struttura elettronica e le prestazioni delle celle solari

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to ...

Fabrication and Testing of Photonic Thermometers

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being leveraged for developing sophisticated photonic sensors. Silicon photonic sensors seek to exploit the strong confinement of light in nano-waveguides to transduce changes in physical state to changes in resonance frequency. In the case of thermometry, the thermo-optic coefficient, i.e., changes in refractive index due to temperature, causes the resonant frequency of the photonic device such as a Bragg grating to drift with temperature. We are developing a suite of photonic devices that leverage recent advances in telecom compatible light sources to fabricate cost-effective photonic temperature sensors, which can be deployed in a wide variety of settings ranging from controlled laboratory conditions, to the noisy environment of a factory floor or a residence. In this manuscript, we detail our protocol for the fabrication and testing of photonic thermometers.

We describe the process of fabrication and testing of photonic thermometers.

Fabbricazione e collaudo di termometri fotonici

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

Fabbricazione e collaudo di aerogel catalitico preparato tramite rapida estrazione supercritica

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Preparation of Poly(pentafluorophenyl acrylate) Functionalized SiO2 Beads for Protein Purification

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent immunoprecipitation (IP) application. The poly(PFPA) grafted surface is prepared via a simple two-step process. In the first step, 3-aminopropyltrimethoxysilane (APTMS) is deposited as a linker molecule onto the silica surface. In the second step, poly(PFPA) homopolymer, synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization, is grafted to the linker molecule through the exchange reaction between the pentafluorophenyl (PFP) units on the polymer and the amine groups on APTMS. The deposition of APTMS and poly(PFPA) on the silica particles are confirmed by X-ray photoelectron spectroscopy (XPS), as well as monitored by the particle size change measured via dynamic light scattering (DLS). To improve the surface hydrophilicity of the beads, partial substitution of poly(PFPA) with amine-functionalized poly(ethylene glycol) (amino-PEG) is also performed. The PEG-substituted poly(PFPA) grafted silica beads are then immobilized with antibodies for IP application. For demonstration, an antibody against protein kinase RNA-activated (PKR) is employed, and IP efficiency is determined by Western blotting. The analysis results show that the antibody immobilized beads can indeed be used to enrich PKR while non-specific protein interactions are minimal.

Preparation of Polypentafluorophenyl acrylate Functionalized SiO2 Beads for Protein Purification

A protocol for the preparation of poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads is presented. The poly(PFPA) functionalized surface is then immobilized with antibodies and used successfully for the protein separation through immunoprecipitation.

Preparazione di Poly(pentafluorophenyl acrylate) funzionalizzati SiO2 perline per la purificazione della proteina

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent ...

Fabrication of Thin Film Silver/Silver Chloride Electrodes with Finely Controlled Single Layer Silver Chloride

This paper aims to present a protocol to form smooth and well-controlled films of silver/silver chloride (Ag/AgCl) with designated coverage on top of thin film silver electrodes. Thin film silver electrodes sized 80 &#181;m x 80 &#181;m and 160 &#181;m x 160 &#181;m were sputtered on quartz wafers with a chromium/gold (Cr/Au) layer for adhesion. After passivation, polishing and cathodic cleaning processes, the electrodes underwent galvanostatic oxidation with consideration of Faraday&#39;s Law of Electrolysis to form smooth layers of AgCl with a designated degree of coverage on top of the silver electrode. This protocol is validated by inspection of scanning electron microscope (SEM) images of the surface of the fabricated Ag/AgCl thin film electrodes, which highlights the functionality and performance of the protocol. Sub-optimally fabricated electrodes are fabricated as well for comparison. This protocol can be widely used to fabricate Ag/AgCl electrodes with specific impedance requirements (e.g., probing electrodes for impedance sensing applications like impedance flow cytometry and interdigitated electrode arrays).

This paper aims to present a method to form smooth and well-controlled films of silver chloride (AgCl) with designated coverage on top of thin film silver electrodes.

Fabbricazione di elettrodi a pellicola d'argento/argento con cloruro d'argento a livello singolo finemente controllato

This paper aims to present a protocol to form smooth and well-controlled films of silver/silver chloride (Ag/AgCl) with designated coverage on top of thin ...

Perle modificate con porfirina in citometria a flusso

Porphyrin-Modified Beads for Use as Compensation Controls in Flow Cytometry

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or more fluorescent reagents, each functionalized with a different fluorescent molecule (fluorophore) that binds to cells selectively based on their phenotypic characteristics, such as cell surface antigen expression. The intensity of fluorescence from each reagent bound to cells can be measured on the flow cytometer using channels that detect a specified range of wavelengths. When multiple fluorophores are used, the light from individual fluorophores often spills over into undesired detection channels, which requires a correction to the fluorescence intensity data in a process called compensation. 
Compensation control particles, typically polymer beads bound to a single fluorophore, are needed for each fluorophore used in a cell labeling experiment. Data from compensation particles from the flow cytometer are used to apply a correction to the fluorescence intensity measurements. This protocol describes the preparation and purification of polystyrene compensation beads covalently functionalized with the fluorescent reagent meso-tetra(4-carboxyphenyl) porphine (TCPP) and their application in flow cytometry compensation. In this work, amine-functionalized polystyrene beads were treated with TCPP and the amide coupling reagent EDC (N-(3-dimethylaminopropyl)-N&#8242;-ethylcarbodiimide hydrochloride) at pH 6 and at room temperature for 16 h with agitation. The TCPP beads were isolated by centrifugation and resuspended in a pH 7 buffer for storage. TCPP-related particulates were observed as a byproduct. The number of these particulates could be reduced using an optional filtration protocol. The resultant TCPP beads were successfully used on a flow cytometer for compensation in experiments with human sputum cells labeled with multiple fluorophores. The TCPP beads proved stable following storage in a refrigerator for 300 days.

Autore in primo piano: Perle modificate con porfirina da utilizzare come controlli di compensazione nella citometria a flusso  

The protocol describes how porphyrin-based compensation beads for flow cytometry are prepared by the reaction of amine-functionalized polystyrene beads with the porphyrin TCPP and the amide coupling reagent EDC. A filtration procedure is used to reduce the particulate byproducts.

Perle modificate con porfirina da utilizzare come controllo di compensazione nella citometria a flusso

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or ...