Este trabajo ha sido apoyado por Ogden Facultad de Ciencias e Ingeniería, incluyendo soporte interno del Departamento de Química y de la Oficina de Investigación (RCCA 13-8032) de la Universidad de Western Kentucky. La asistencia del Dr. John Andersland en la Instalación WKU Microscopía (imágenes SEM) y Profesor Asociado Yan Cao del Instituto WKU para combustión Ciencia e Ingeniería (análisis BET) ha sido fundamental para la realización de este trabajo.

1. Preparación de la Emulsión <ol><li> Contenido de emulsión <ol><li> Masa una cantidad apropiada de sal para producir 10 ml de una solución de 0,03-M. Por platino (IV) medida cloruro de 0.101 g, para el zinc (II) (ZnCl2) medida 0.032 g, y cloruro de sodio (NaCl) medida 0.018 g. </li><li> En tubos de ensayo individuales, cada disolver la sal en 10 ml de agua DI. Ponga a un lado para su uso posterior. </li><li> Utilice a 20 ml, vial de vidrio se puede sellar de los contenidos a través de este procedimiento. Tare un equilibrio al vial de vidrio. </li><li> Pesar polidimetilsiloxano terminado en vinilo vertiendo lentamente sobre una barra de agitación y en el vial de vidrio descansando en la escala de cero. Pesar 1,02 g (equivalente a 1.080 ml). NOTA: La alta viscosidad de este polímero hace pipeteo poco práctico. </li><li> Pipetear 1,02 ml de n-heptano para el vial. Añadir 2 gotas de (monooleato de sorbitán) tensioactivo no iónico al vial. Pipetear 0,3 ml de solución salina y 0,45 ml de DI-agua al vial. </li><li> Sellar el vial de vidrio atornillando la tapa firmemente. Agitar vigorosamente durante 60 segundos para iniciar la emulsión antes de iniciar tratamiento con ultrasonidos. </li></ol></li><li> Construcción de agua-baño Sonicator Aparato <ol><li> Llena de ultrasonidos con agua hasta la línea de llenado mínimo. Añadir 250 ml de agua del grifo a un vaso de 400 ml. Llenar el vaso de precipitados de 400 ml con hielo de modo que el nivel de agua es sólo en el borde. </li><li> Coloque este vaso de precipitados en el interior del aparato de ultrasonidos baño de agua. Compruebe la línea de llenado en el aparato de ultrasonidos, ajustar si es necesario. Coloque un anillo de pie justo al lado del aparato de ultrasonidos baño de agua. </li><li> El uso de dos anillos de pie abrazaderas, colóquelos de manera que un brazo se extiende hacia fuera, perpendicular al anillo de pie y otro se extiende hacia el baño de agua de manera que quede apuntando hacia abajo en el vaso lleno de agua helada. Añada otra pinza para el anillo de soporte con un termómetro en el vaso de precipitados de 400 ml para que la temperatura se puede controlar a través de sonicación. </li></ol></li><li> EmulsifProcedimiento icación <ol><li> Colocar el vial que contiene la emulsión de manera que está completamente sumergido en el vaso de precipitados de 400 ml, asegurando que en la abrazadera que sobresale hacia abajo en el vaso de precipitados. </li><li> Asegúrese de que el vial de vidrio que contiene la mezcla de PDMS no está en contacto con los lados del vaso de precipitados para eliminar el calor causado por la fricción. </li><li> Encienda el aparato de ultrasonidos y establecer el tiempo de tratamiento con ultrasonidos durante 7 minutos. Debido a que la emulsión es muy sensible al calor, asegurar que la temperatura en el interior del vaso de precipitados está entre 0 y 5 ° C a lo largo de sonicación. Iniciar la sonicación una vez que la temperatura en el interior del vaso de precipitados es deseable. </li><li> Después de 7 minutos de sonicación, retire el vial y agítelo suavemente / remolino durante 1 minuto, sosteniendo la parte superior del vial para eliminar los grumos que podrían formar en la emulsión. </li><li> Deseche el contenido del vaso de precipitados. Vuelva a llenar con 250 ml de agua y añadir hielo para el relleno dentro de 1 cm de la parte superior del vaso de precipitados. </li><li> Coloque el vial hacia atrás en el gancho. Sumergirlo bajo el agua helada para Resume sonicación durante 7 min. </li><li> Repetir los pasos 1.3.3 a 1.3.6 para un total de períodos de sonicación ocho, 7-min, o hasta que la sonicación parece ser homogénea y sin grumos están presentes. Guarde a temperatura ambiente. NOTA: La emulsificación debe ser estable durante varios días, pero puede ser recuperado por sonicación como anteriormente en intervalos de 7 min hasta que aparece homogénea. Guarde a temperatura ambiente. </li></ol></li></ol> 2. La reticulación <ol><li> Configuración de adición de trietoxisilano Solución / surfactante <ol><li> Pipetear 5,4 ml trietoxisilano en un tubo de ensayo. Coloque en un bastidor de tubo de ensayo bajo el capó para su uso posterior. </li><li> Llene un vaso de 400 ml con agua helada y colocarlo bajo el capó. Junto al lugar vaso de 400 ml un anillo de pie con una pinza unida, extendido directamente sobre la apertura del vaso de precipitados. Este será el baño de hielo durante la adición de trietoxisilano. </li><li> Coloque un plato caliente en el otro lado de la base del anillo. Llenar un vaso de precipitados de 800 ml con aproximadamente 700 ml deagua del grifo. Colocar en el plato caliente. </li><li> Encienda la placa caliente y mantener una temperatura de 75 a 85 ° C en el interior del vaso de precipitados de 800 ml. Adjuntar una abrazadera con un termómetro para el soporte de anillo de modo que la temperatura del agua dentro del vaso de precipitados de 800 ml se puede controlar. </li><li> Producir la solución de tensioactivo disolviendo 0,5 g de dodecilsulfato de sodio a 375 ml de agua (4,62 mm). Añadir aproximadamente 10 ml de solución de tensioactivo a un tubo de ensayo limpio, vacío. </li><li> Añada otra pinza para el anillo de soporte bajo el capó con el tubo de ensayo tensioactivo fijado de manera que su nivel de líquido está por debajo de la superficie del agua dentro del vaso de precipitados de 800 ml. Permita 10 minutos para el equilibrio térmico. </li><li> Humedezca un pedazo de papel de filtro y colocarlo en la parte superior de un pequeño embudo. Coloque el vástago del embudo dentro de un matraz Erlenmeyer de 250 ml y se coloca el matraz bajo el capó. </li></ol></li><li> La adición de trietoxisilano <ol><li> Colocar el vial emulsión en la abrazadera sobre el pico de agua con hieloer interior de la campana. Coloque la mezcla de PDMS en la abrazadera de manera que el contenido del vial por debajo de la superficie del agua. La adición de trietoxisilano provoca una reacción exotérmica, por lo que la emulsión se debe mantener frío el fin de mantener su estructura. </li><li> Retire la tapa del frasco de vidrio para evitar la acumulación de gases. </li><li> Verter lentamente la trietoxisilano tubo de ensayo que contiene en el vial de vidrio en una corriente continua durante un periodo de aproximadamente 10 segundos (aproximadamente 0,5 ml / seg). PRECAUCIÓN: La adición de trietoxisilano inicia una reacción exotérmica y la liberación de cloruro de hidrógeno cáustica (HCl) de gas. El vial se convertirá en extremadamente caliente y un gas tóxico evolucionará de la mezcla. No revuelva el contenido al tiempo que añade el trietoxisilano. </li><li> Después de añadir trietoxisilano completamente, revuelva suavemente el contenido con una varilla agitadora de vidrio mientras lleva puesto un guante protector de calor. Espere 2 minutos o hasta que deje de gas evolución del vial. </li><li> Folldebido reticulación, no hay ninguna separación de fases visible en la muestra. Si están presentes grupos, sellar el vial y agitar durante 20 segundos rigurosamente mientras se mantiene el vial por la tapa. </li></ol></li><li> La producción del grano <ol><li> Utilice una pipeta Pasteur de vidrio limpio para sacar la emulsión reticulado del vial de vidrio. Añadir la emulsión reticulado gota a gota a la solución de tensioactivo (que debe mantenerse entre 75 y 85 ° C) en el tubo de ensayo teniendo tan poco tiempo como sea posible en entre gotas. </li><li> 30 seg a 1 min después de la adición de la emulsión, la solución de tensioactivo poco a poco empezar a desprender gas en forma de sólidos comienzan a formarse en el interior del tubo de ensayo. </li><li> Mientras que el uso de guantes protectores de calor, tome el tubo de ensayo de la abrazadera y vierta todo su contenido en el aparato de filtración bajo el capó. Filtro para 5 min. Retire el papel de filtro del filtro. </li><li> La transferencia de los sólidos filtrados en un vidrio de reloj y cuentas separadas para O / N secado bajo el hud. Limpieza de las perlas puede posponerse indefinidamente. Tienda secó perlas a temperatura ambiente en un vial de vidrio sellado hasta que se necesite, y limpia inmediatamente antes de su uso. </li></ol></li><li> Servicio de limpieza del grano <ol><li> Cree otro aparato de filtración bajo el capó y colocar las perlas secas en el interior del embudo en la parte superior del papel de filtro. </li><li> Utilice una botella de lavado de plástico llena de DI-agua para enjuagar los granos suavemente, moverlos ligeramente para asegurar que todas las perlas se enjuagan. </li><li> Deje que los granos se secan durante 1 hora colocándolos en un vidrio de reloj bajo el capó. Utilice una botella de lavado llena con hexanos para enjuagar las perlas usando el mismo método para enjuagar con agua. </li><li> Coloque las bolas en un vidrio de reloj. Coloque el vidrio de reloj y las cuentas bajo el capó se sequen. </li><li> Después de que los granos estén completamente secas, colocarlas en un pequeño frasco de vidrio se puede sellar y almacenar a temperatura ambiente para su uso futuro. </li></ol></li><li> Montaje de las Cuentas para Configuración de análisis SEM y SEM <ol><li> Coloque una tira de tareas pendientescarbono cinta conductora-uble cara en la parte superior del talón sobre el cual se montan las perlas. Con unas tijeras, corte alrededor del talón para asegurar que no se cuelga de la cinta en los bordes. </li><li> Coloque un pedazo de papel de filtro bajo el talón sobre una superficie plana. Quite la capa superior de la cinta para que la parte inferior adhesiva está expuesta. </li><li> Vierta suavemente los granos sobre el trozo. Algunas cuentas se adhieren a la cinta, pero la mayoría se recuperará despegar y aterrizar en el papel de filtro. Vierta éstos de nuevo en el vial si se quedaban en el papel de filtro. Repita si es necesario, lavar las cuentas (de acuerdo con 2.4.2 a 2.4.5) que se contaminan. </li><li> Para asegurar las cuentas son seguras en el talón, utilizar una pera de goma y ligeramente soplar muy de cerca a la superficie trozo. Verter más cuentas sobre el stub si sólo unos pocos adherida a la cinta. Asegúrese de que todos los granos son seguras antes de colocar el talón en la cámara de SEM y la evacuación de la misma. </li><li> Una vez que las muestras se han montado correctamente que ahora están dispuestos a someterse a SEM analanalysis 15. Recoge imágenes en el modo LOW VAC a 15 keV para optimizar la resolución de los rasgos de la superficie de la perla. </li></ol></li></ol>

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The authors have nothing to disclose.

Las perlas producidas usando este protocolo (y ajustando la concentración de electrolitos y la identidad) son fundamentalmente diferentes de los producidos con una emulsión de baja fuerza iónica, como se ve por la comparación de la figura 1A a las otras imágenes de SEM en la Figura 1. Nuestro informe inicial utilizados PtCl4 con la intención de catalizar la polimerización ulterior reticulación en la interfase acuosa alifático-14...

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.

Imágenes de SEM representativos de perlas que surgen a partir de emulsiones con diferentes condiciones de electrolitos se muestran en la Figura 1. La Figura 1A muestra un cordón similar a los obtenidos por Dufaud, et al. 13, producido usando nuestros procedimientos, sin la adición de cualquier electrolito. Beads muestran en la Figura 1B-D, lo que resulta en diferentes morfologías para cada ion metálico. Para todas las imágenes que se muestran, ...

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.

Fabricación de microburbujas de Cuentas PDMS Cóncavo porosidad

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

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Chemistry

8.2K vistas.  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.

La fabricación de superficies de gran autoportante ultrafinos Polymer Films

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

Investigación

Química

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-patrón Fabricación guiada de alta densidad de códigos de barras de anticuerpos microarrays

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.

La inmovilización de Multi-biocatalizadores en perlas de alginato de cofactor de Regeneración y Reutilización mejorada

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.

Influencia de los híbridos Métodos de Fabricación perovskita en la formación de película, Estructura electrónica y el rendimiento de la célula solar

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.

Fabricación y pruebas de termómetros fotónicos

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.

Fabricación y pruebas de Aerogels catalíticos preparados vía rápida extracción supercrítica

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.

Preparación de Poly(pentafluorophenyl acrylate) funcionalizados SiO2 cuentas para purificación de proteínas

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.

Fabricación de electrodos de cloruro de plata/plata de película delgada con cloruro de plata de una sola capa finamente controlado

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 ...

Perlas modificadas con porfirina en citometría de flujo

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.

Autor destacado: Perlas modificadas con porfirina para su uso como controles de compensación en citometría de flujo  

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.

Perlas modificadas con porfirina para uso como controles de compensación en citometría de flujo

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