Agradecemos a Deborah Studer para la ayuda con el bioprinter. El trabajo fue financiado por el Séptimo Programa Marco de la Unión Europea (FP7/2007-2013), bajo acuerdo de subvención n ° NMP4-SL-2009 hasta 229.292.

1. Preparación de la solución de 407 Poloxámero Si está disponible, lleve a cabo la preparación de la solución de poloxámero en una habitación fría (4 ° C). Si no está disponible, colocar una botella de vidrio en un vaso de precipitados lleno de agua enfriada con hielo. A temperaturas más altas el poloxámero estará por encima del punto de gel y no se disuelve apropiadamente. <ol><li> Añadir 60 ml de solución de PBS frío de hielo en una botella de vidrio y se agita vigorosamente con un agitador magnético. </li><li> Pesar 24,5 gramos de poloxámero y añadirlo en pequeñas cantidades a la PBS frío. Espere hasta que el poloxámero han disuelto antes de añadir más. </li><li> Se agita la solución hasta que se haya disuelto todo el poloxámero. </li><li> Añadir PBS frío hasta que se alcanza un volumen final de 100 ml. La concentración final será de 24,5% w / v </li><li> Deja de agitar la solución y se deja reposar a 4 ° C hasta que las burbujas y la espuma en la solución han desaparecido. Las burbujas que son atrapadas dentro del gel se transfirieron a la pcartucho IMPRESORA y dará lugar a defectos en los moldes de sacrificio impresos. </li><li> Filtro (filtro de 0,22 micras) la solución directamente en el cartucho de impresión para eliminar las partículas no deseadas que podrían obstruir la aguja. La etapa de filtración se debe realizar en una habitación fría (o si no está disponible con las puntas enfriados, filtro, etc) para evitar la gelificación de la poloxámero en el filtro. Mantenga el cartucho cargado a 4 ° C hasta 30 minutos antes del experimento. </li></ol> 2. Preparación de la impresora 3D La impresora 3D utilizado en este trabajo fue el &quot;Biofábrica&quot; ​​de regenHU. La parte del sistema de extrusión consta de varias partes. Un cartucho a presión en la parte superior está unida a un conector a través de un adaptador de cierre luer. El conector de puente entre los espacios entre la salida del cartucho y la entrada de una válvula de solenoide. A la salida de la válvula de solenoide, agujas de diferentes diámetros se pueden utilizar. El material se extruye sobre un subtrar que se mantiene a una etapa en movimiento por medio de vacío. Las partes principales del sistema se representan en la Figura 1. Otros sistemas basados ​​en extrusión se pueden utilizar para el proceso de impresión, y el proceso de optimización que hay que hacer para cada sistema. <ol><li> Coloque la válvula de solenoide (diámetro de la boquilla 0,3 mm) y la aguja (diámetro interior 0,15 mm) en tubos de ensayo separados 1,5 ml llenos con agua ultrapura y colocarlas en un baño de ultrasonidos para limpiar climatizada durante 30 min. Enjuague las válvulas limpias con etanol y secar con una pistola de nitrógeno. </li><li> Instalar la válvula y la aguja en la impresora, así como un, cartucho vacía y limpia. </li><li> Aplicar 3 bar de presión en el sistema y apagar todos los líquidos residuales de la válvula instalada y la aguja con aire a presión. Para los pequeños diámetros de aguja, se recomienda tener un filtro (filtro de jeringa común, 0,45 micras de tamaño de poro) instalado en la salida del aire comprimido para evitar la entrada de pequeñas partículas que podrían obstruir la aguja. </li&gt; <li> Gire a la presión e instalar el cartucho cargado con el poloxámero. El cartucho se debe tomar de la nevera aproximadamente 30 min antes de montar el cartucho de manera que el poloxámero puede alcanzar la temperatura ambiente y el gel. </li><li> Aplicar 3 bar de presión para el sistema y dispensar poloxámero hasta que llega a la punta de la aguja y se extruye en una hebra continua. </li></ol> 3. Optimización de los parámetros de impresión Para crear estructuras 3D precisos, el proceso de impresión tiene que ser optimizado para el material elegido y de la concentración. Dependiendo de la viscosidad y el sistema de impresión 3D cada material se dió un volumen de dispensación específica y grosor de la línea para un conjunto fijo de parámetros. <ol><li> Con un software CAD adecuado (capaz de crear archivos ISO de los dibujos), dibujar una sola línea acerca de la misma longitud que la estructura que se va a imprimir. </li><li> Coloque un microscopio portaobjetos 25 mm x 75 mm x 1mm o cualquier otro sustrato en la impresora y asegurar que girando en el vacío. </li><li> En el software de la impresora, coloque la válvula de solenoide de alta frecuencia de 50 Hz y establecer una alta presión de 3 bar. </li><li> Imprimir una capa de una sola línea con una velocidad de fase de 300 mm / min. </li><li> Reducir la presión hasta alcanzar el ancho de la línea deseada. También se puede controlar el volumen que se extruye a través del tiempo de apertura de la válvula. </li><li> Reducir la frecuencia de la válvula hasta que hay una línea continua se puede imprimir más. Elija una frecuencia por encima de este valor. </li></ol> Nota: Una vez que se alcanzan el grosor de línea deseado y líneas continuas, determinar la velocidad de fase óptima y espesor de la capa es decir, la elevación de la aguja después de una capa impresa. <ol start="7"><li> Imprima varias capas una encima de la otra y ver si la aguja está en la posición correcta sobre la capa anterior después de varias capas impresas. Ajustar el espesor de la capa (ascensor aguja) De modo que cada capa se imprime en la parte superior de la siguiente (Figura 3). </li><li> Reduzca la velocidad de fase de la etapa de 300 mm / min paso a paso de manera que las capas extruidas comienzan y terminan en las mismas posiciones que los anteriores (Figura 4). Velocidades demasiado altas escenario hacen que el escenario para estar en movimiento antes de que el material extruido ha tocado la capa anterior. </li><li> Para la impresión de las estructuras pilar siguen los pasos 3.1.-3.8., Pero en vez de dibujar una sola línea dibujan un solo punto. Los parámetros para centrarse en la hora de imprimir los pilares son la presión (regula espesor de la capa y el diámetro del pilar de poloxámero), el tiempo de apertura de la válvula (volumen extruido) y el tiempo de residencia de la cabeza de impresión en la posición donde el pilar debe ser depositado . </li><li> Cuando se optimizan los parámetros, la impresión de varias capas de una línea debe resultar en una pared sólida, o en el caso de los puntos, un pilar. Guardar los parámetros para su uso posterior. </li></ol> Utilice los parámetros encontrados durante el proceso de optimización a partir de ahora. <ol><li> Imprimir la estructura interna (en este caso se trata de una matriz pilar) sobre un portaobjetos de vidrio y deje que se seque durante la noche. Esto a) reduce el tamaño y el grosor de las estructuras y b) proporciona una mejor adhesión entre la estructura y el sustrato, por lo que el despegue durante el relleno puede ser evitado. </li><li> Con el software de CAD, dibuje una estructura que consiste en una pared exterior que rodea la estructura va a haber eluido lejos y lleno. Imprimir la estructura con poloxámero. La impresión de la pared tendrá 6 min. </li></ol> Atención: La pared tiene que ser impresa al menos 3,5 mm de la estructura interna, debido a las dimensiones de la aguja. De lo contrario la impresión de la pared exterior va a destruir la estructura interna <ol start="3"><li> Preparar la solución que desea rellenar el sacrmolde ificial con (aquí agarosa al 1% en agua desionizada). La solución de agarosa debe tener una temperatura entre 35 ° C y 45 ° C. Por debajo de esta temperatura, la agarosa se solidifica demasiado rápidamente; encima de esta temperatura, que podría destruir los pilares impresos debido a que la estructura de poloxámero se ablandará. </li><li> Llene lentamente el molde de sacrificio con la solución de relleno con una pipeta. Esto se debe hacer lentamente para evitar la destrucción de la estructura dentro de la pared. </li><li> Deje que el gel de solución rellenada o reticular que dependiendo del polímero utilizado. En el caso de la solidificación de agarosa se llevó a cabo a 4 º C durante 10 min. </li><li> Colocar el molde de sacrificio rellenada en un baño de hielo durante 10 min para eluir la estructura de poloxámero. </li><li> Seque la estructura rellenada con un pañuelo de papel y colocarlo en un nuevo portaobjetos de vidrio. Pulse la estructura cuidadosamente sobre el portaobjetos de microscopio de vidrio para evitar la fuga de la tercera hidrogel desde el vacío en el espacio entrela estructura rellenada y el portaobjetos de microscopio de vidrio. </li></ol> 5. El llenado de los huecos <ol><li> Para llenar los huecos dejados por el poloxámero eluido, llenar la solución de polímero deseado en una jeringa equipada con una aguja de 30 G. En este ejemplo, se utilizó un metacrilato de alginato al 1% en solución 0,15 M de NaCl con la adición de 0,05% w / v de litio fenil-2, 4,6-trimethylbenzoylphosphinate (LAP) y 2,5% v / v de Alexa-488 fibrinógeno conjugado . El Alexa-488 conjugado fibrinógeno fue agregada para fines de visualización. </li><li> Fotopolimerizar el polímero con una lámpara de UV de alta intensidad (100 vatios, 365 nm, distancia del substrato fue de 3,5 cm) durante 5 min y la imagen de la construcción usando un microscopio de epi-fluorescencia o confocal. </li></ol>

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Tissue. 6, 302-302 (2012).</li><li>Butterworth, A., Garcia, M. D. L., Beebe, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photopolymerized+poly(ethylene)+glycol+diacrylate+(PEGDA)+microfluidic+devices.">Photopolymerized poly(ethylene) glycol diacrylate (PEGDA) microfluidic devices.</a> Roy. Soc. Ch. , 4-6 (2005).</li><li>Shachar, M., Tsur-Gang, O., Dvir, T., Leor, J., Cohen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+immobilized+RGD+peptide+in+alginate+scaffolds+on+cardiac+tissue+engineering.">The effect of immobilized RGD peptide in alginate scaffolds on cardiac tissue engineering.</a> Acta biomaterialia. 7, 152-162 (2011).</li><li>Jeon, O., Bouhadir, K. H., Mansour, J. M., Alsberg, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photocrosslinked+alginate+hydrogels+with+tunable+biodegradation+rates+and+mechanical+properties.">Photocrosslinked alginate hydrogels with tunable biodegradation rates and mechanical properties.</a> Biomaterials. 30, 2724-2734 (2009).</li><li>Mauck, R. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+tissue+engineering+of+articular+cartilage+through+dynamic+loading+of+chondrocyte-seeded+agarose+gels.">Functional tissue engineering of articular cartilage through dynamic loading of chondrocyte-seeded agarose gels.</a> J. Biomech. Eng-T Asme. 122, 252-260 (2000).</li><li>D'Arrigo, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyaluronic+acid+methacrylate+derivatives+and+calcium+alginate+interpenetrated+hydrogel+networks+for+biomedical+applications:+physico-chemical+characterization+and+protein+release.">Hyaluronic acid methacrylate derivatives and calcium alginate interpenetrated hydrogel networks for biomedical applications: physico-chemical characterization and protein release.</a> Colloid Polym. Sci. 290, 1575-1582 (2012).</li><li>Pescosolido, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyaluronic+Acid+and+Dextran-Based+Semi-IPN+Hydrogels+as+Biomaterials+for+Bioprinting.">Hyaluronic Acid and Dextran-Based Semi-IPN Hydrogels as Biomaterials for Bioprinting.</a> Biomacromolecules. 12, 1831-1838 (2011).</li><li>Guo, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogels+of+collagen/chondroitin+sulfate/hyaluronan+interpenetrating+polymer+network+for+cartilage+tissue+engineering.">Hydrogels of collagen/chondroitin sulfate/hyaluronan interpenetrating polymer network for cartilage tissue engineering.</a> J. Mater. Sci-Mater. M. 23, 2267-2279 (2012).</li></ol>

Los autores no tienen nada que declarar.

Aquí se presenta, por primera vez, el uso de un polímero termosensible para un molde de sacrificio que se pueden eluyó rápidamente en agua fría debido a la transición de gel-sol de poloxámero de ~ 20 ° C. La velocidad de todo el proceso de poloxámero hace interesante para la rápida creación de estructuras de biopolímeros que no se puede imprimir con una resolución adecuada. La técnica descrita aquí puede ser utilizado para modelar un hidrogel dentro de otro hidrogel o para la creación de canales de micro...

Enfoques de ingeniería de tejidos han avanzado mucho en los últimos años con respecto a la regeneración de tejidos y órganos humanos 19,20. Sin embargo, hasta ahora, el enfoque de la ingeniería de tejidos ha sido a menudo limitado a los tejidos que tienen una estructura simple o de pequeñas dimensiones, tales como la vejiga o la piel 21,22 23-25. El cuerpo humano, sin embargo, contiene muchos tejidos tridimensionales complejas en las que las células y la matriz extracelular están dispuestos de una manera espacialmente definido. Para la fabricación de estos tejidos, se requiere una técnica que puede colocar las células y los andamios de matriz extracelular dentro de una construcción de tres dimensiones en las posiciones especificadas. Bioprinting tiene el potencial de ser una técnica tal donde la visión de la fabricación de tejidos tridimensionales complejas puede ser realizado 10,11,26-28. Bioprinting se define como &quot;el uso de los procesos de transferencia de material para modelar y montaje biológicamente relmateriales nentes - moléculas, células, tejidos y biomateriales biodegradables. - con una organización prescrita para llevar a cabo una o más funciones biológicas &quot;4 abarca varias técnicas diferentes que funcionan a diferentes resoluciones y escalas de longitud, que van desde la resolución sub-micras de dos polimerización de fotón 29 a una resolución de 150 micras a 420 micras para la impresión de extrusión 1,12,30. No es un único material o combinación de materiales va a satisfacer los requisitos de cada método 31. Para la impresión de extrusión, los parámetros clave son la viscosidad y el tiempo de gelificación 32, donde son deseables alta viscosidad y gelificación rápida. La impresión 3D es una técnica que permite la fácil creación de moldes de sacrificio para crear geometrías complejas 30,33,34. Este proceso se basa en la construcción de un molde usando una técnica de prototipado rápido tal como un bioprinter extrusión. Se utiliza el molde de sacrificio creadopara formar estructuras complejas a partir de materiales que son difíciles de imprimir, debido a su baja viscosidad y tiempo de gelificación lenta. El método que aquí se presenta implica la creación de un molde de sacrificio consiste en un material que se disuelve rápidamente a baja temperatura y puede ser extruido con precisión. El bloque de copolímero de poli (etileno glicol) 99-poli (propilenglicol) 67-poli (etilenglicol) 99 (también conocido como Pluronic F127 o poloxámero 407) cumple estos requisitos. Ya se ha utilizado en una versión modificada en la impresión de extrusión 1, pero, a nuestro conocimiento, nunca se ha utilizado para la impresión en su versión sin modificar debido a su inestabilidad en ambientes líquidos. Poloxámero 407 también muestra un comportamiento de respuesta térmica inversa 18 es decir, que cambia de un gel a un sol tras el enfriamiento. Lo más importante es que se puede imprimir en las estructuras arbitrariamente curvas complejas con muy alta fidelidad. Esto permite la creación de un hidrogel estructurado a partir de unmaterial de baja viscosidad, en este caso de gelificación lenta de agarosa, con la pipeta la solución en el molde de sacrificio impreso. La combinación de la impresión del molde de sacrificio con alta fidelidad, y su elución rápida del hidrogel estructurado fundido hace que sea un método rápido y flexible para crear moldes con diferentes geometrías sin el uso de una máscara o un sello, ya que se requiere a menudo en métodos litográficos. El hidrogel estructurado fundido puede llenarse aún más con otro material que no es adecuado para la impresión de extrusión debido a su baja viscosidad. Esto es, en nuestro caso una solución metacrilato alginato de baja viscosidad. Aquí presentamos el método de sacrificio termosensible moldes inversa para modelar hidrogel utilizando el ejemplo de una matriz de pilar.

<table border="1">
 <tbody>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>REAGENTS</td>
 </tr>
 <tr>
 <td>Poloxamer (Pluronic F127)</td>
 <td>Sigma</td>
 <td>P2443</td>
 <td ></td>
 </tr>
 <tr>
 <td>PBS</td>
 <td>Invitrogen</td>
 <td><a href="http://products.invitrogen.com/ivgn/en/US/adirect/invitrogen?cmd=catProductDetail&amp;productID=10010015" target="_blank">10010-015</a></td>
 <td ></td>
 </tr>
 <tr>
 <td>CAD software</td>
 <td>regenHU</td>
 <td>BioCAD</td>
 <td ></td>
 </tr>
 <tr>
 <td>Alginate methacrylate</td>
 <td>Innovent e.V Technologieentwicklung Jena</td>
 <td></td>
 <td >Synthesized by Innovent for the FP7 Project Nr NMP4-SL-2009-229292</td>
 </tr>
 <tr>
 <td>Fibrinogen From Human Plasma, Alexa Fluor 488 Conjugate</td>
 <td>Invitrogen</td>
 <td>F13191</td>
 <td ></td>
 </tr>
 <tr>
 <td>Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP)</td>
 <td>Innovent e.V Technologieentwicklung Jena</td>
 <td></td>
 <td >Synthesized by Innovent for the FP7 Project Nr NMP4-SL-2009-229292</td>
 </tr>
 <tr>
 <td>Agarose</td>
 <td>Lonza</td>
 <td>50004</td>
 <td ></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>EQUIPMENT</td>
 </tr>
 <tr>
 <td>Bioprinter</td>
 <td>regenHU</td>
 <td>Biofactory</td>
 <td ></td>
 </tr>
 <tr>
 <td>Valve</td>
 <td>regenHU</td>
 <td>300 &mu;m Nozzel Diameter</td>
 <td ></td>
 </tr>
 <tr>
 <td>Needle</td>
 <td>regenHU</td>
 <td>150 &mu;m Inner Diameter</td>
 <td ></td>
 </tr>
 <tr>
 <td>Zeiss Axioobserver with ApoTome</td>
 <td>Zeiss</td>
 <td></td>
 <td ></td>
 </tr>
 <tr>
 <td>UV Light Source</td>
 <td>UVP</td>
 <td>Blak-Ray B-100AP High Intensity UV Lamp</td>
 <td>100 W</td>
 </tr>
 </tbody>
</table>

printing thermoresponsive reverse molds for the creation of patterned two-component hydrogels for 3d cell culture

Bioprinting es una tecnología emergente que tiene su origen en la industria del prototipado rápido. Los procesos de impresión diferentes se pueden dividir en bioprinting contacto 1-4 (extrusión, pluma de la inmersión y la litografía blanda), 5-7 (transferencia de láser hacia adelante, la deposición de chorro de tinta) sin contacto bioprinting y técnicas basadas en láser, tales como dos fotones fotopolimerización 8. Se puede utilizar para muchas aplicaciones tales como la ingeniería de tejidos 9-13, 14-16 y microfabricación biosensor como una herramienta para responder a las preguntas biológicas básicas tales como las influencias de co-cultivo de diferentes tipos de células 17. A diferencia de métodos fotolitográficos o suave-litográfica comunes, bioprinting extrusión tiene la ventaja de que no requiere una máscara o sello separado. El uso de software CAD, el diseño de la estructura se puede cambiar rápidamente y ajusta de acuerdo con los requisitos del operador. Esto hace que bioprinting más flexible que la litografía basadaenfoques. Aquí se demuestra la impresión de un molde de sacrificio para crear una estructura de múltiples materiales 3D utilizando una matriz de pilares dentro de un hidrogel como un ejemplo. Estos pilares podrían representar estructuras huecas de una red vascular o los tubos dentro de un conducto de guía del nervio. El material escogido para el molde de sacrificio era poloxámero 407, un polímero termosensible con excelentes propiedades de impresión que es líquida a 4 ° C y un sólido por encima de su temperatura de gelificación ~ 20 ° C durante 24,5 soluciones w / v 18%. Esta propiedad permite que el molde de sacrificio poloxámero basado en que se eluyó en la demanda y tiene ventajas con respecto a la lenta disolución de un material sólido, especialmente para geometrías estrechas. Poloxámero se imprimió en portaobjetos de vidrio para microscopio para crear el molde de sacrificio. La agarosa se pipeteó en el molde y se enfría hasta la gelificación. Después de la elución de la poloxámero en agua fría de hielo, los huecos en el molde de agarosa se llenaron con alginato de metacrilato spIKED con fibrinógeno marcado con FITC. Los huecos llenos fueron entonces reticuladas con UV y el constructo fue fotografiada con un microscopio de epifluorescencia.

Los resultados representativos muestran que la técnica inversa del molde (representado en la Figura 2) va a crear un gel estructurada que puede ser llenado con un segundo material. Al comienzo de cada proceso de impresión los parámetros de impresión están optimizados primero. Ajustes paso a paso de los parámetros darán como resultado construcciones multicapa impresos representadas en la Figura 3 y la Figura 4 cuando se imprimen líneas individuales. Si el espesor...

Watch this Scientific Journal Video about Printing Thermoresponsive Reverse Molds for the Creation of Patterned Two-component Hydrogels for 3D Cell Culture at JoVE.com

Printing Thermoresponsive Reverse Molds for the Creation of Patterned Two-component Hydrogels for 3D Cell Culture

Un bioprinter se utilizó para crear hidrogeles modelado basado en un molde de sacrificio. El molde poloxámero se rellenó con un segundo hidrogel y luego se eluyó, dejando huecos que estaban llenos de una tercera hidrogel. Este método utiliza elución rápida y buena capacidad de impresión de poloxámero para generar arquitecturas complejas a partir de biopolímeros.

Impresión Moldes inversa termosensible para la Creación de modelado hidrogeles de dos componentes para el 3D de cultivo celular

Bioprinting is an emerging technology that has its origins in the rapid prototyping industry. The different printing processes can be divided into contact ...

printing-thermoresponsive-reverse-molds-for-creation-patterned-two

Research

JoVE Journal

Immunology and Infection

15.0K vistas.  Cartilage Engineering & Regeneration. Un bioprinter se utilizó para crear hidrogeles modelado basado en un molde de sacrificio. El molde poloxámero se rellenó con un segundo hidrogel y luego se eluyó, dejando huecos que estaban llenos de una tercera hidrogel. Este método utiliza elución rápida y buena capacidad de impresión de poloxámero para generar arquitecturas complejas a partir de biopolímeros.

Video: Printing Thermoresponsive Reverse Molds for the Creation of Patterned Two-component Hydrogels for 3D Cell Culture

Detection of Infectious Virus from Field-collected Mosquitoes by Vero Cell Culture Assay

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many of these viruses have intensified in their endemic ranges and expanded to new territories, necessitating effective surveillance and control programs to respond to these threats. One strategy to monitor virus activity involves collecting large numbers of mosquitoes from endemic sites and testing them for viral infection. In this article, we describe how to handle, process, and screen field-collected mosquitoes for infectious virus by Vero cell culture assay. Mosquitoes are sorted by trap location and species, and grouped into pools containing &le;50 individuals. Pooled specimens are homogenized in buffered saline using a mixer-mill and the aqueous phase is inoculated onto confluent Vero cell cultures (Clone E6). Cell cultures are monitored for cytopathic effect from days 3-7 post-inoculation and any viruses grown in cell culture are identified by the appropriate diagnostic assays. By utilizing this approach, we have isolated 9 different viruses from mosquitoes collected in Connecticut, USA, and among these, 5 are known to cause human disease. Three of these viruses (West Nile virus, Potosi virus, and La Crosse virus) represent new records for North America or the New England region since 1999. The ability to detect a wide diversity of viruses is critical to monitoring both established and newly emerging viruses in the mosquito population.

We describe a method to process and screen field-collected mosquitoes for a diversity of viruses by Vero cell culture assay. By employing this technique, we have detected 9 different viruses from 4 taxonomic families in mosquitoes collected in Connecticut.

Detección del virus infeccioso de campo recogidos por los mosquitos del ensayo cultivo celular Vero

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many ...

Investigación

Inmunología e Infección

A Primary Neuron Culture System for the Study of Herpes Simplex Virus Latency and Reactivation

Herpes simplex virus type-1 (HSV-1) establishes a life-long latent infection in peripheral neurons. This latent reservoir is the source of recurrent reactivation events that ensure transmission and contribute to clinical disease. Current antivirals do not impact the latent reservoir and there are no vaccines. While the molecular details of lytic replication are well-characterized, mechanisms controlling latency in neurons remain elusive. Our present understanding of latency is derived from in vivo studies using small animal models, which have been indispensable for defining viral gene requirements and the role of immune responses. However, it is impossible to distinguish specific effects on the virus-neuron relationship from more general consequences of infection mediated by immune or non-neuronal support cells in live animals. In addition, animal experimentation is costly, time-consuming, and limited in terms of available options for manipulating host processes. To overcome these limitations, a neuron-only system is desperately needed that reproduces the in vivo characteristics of latency and reactivation but offers the benefits of tissue culture in terms of homogeneity and accessibility.
Here we present an in vitro model utilizing cultured primary sympathetic neurons from rat superior cervical ganglia (SCG) (Figure 1) to study HSV-1 latency and reactivation that fits most if not all of the desired criteria. After eliminating non-neuronal cells, near-homogeneous TrkA+ neuron cultures are infected with HSV-1 in the presence of acyclovir (ACV) to suppress lytic replication. Following ACV removal, non-productive HSV-1 infections that faithfully exhibit accepted hallmarks of latency are efficiently established. Notably, lytic mRNAs, proteins, and infectious virus become undetectable, even in the absence of selection, but latency-associated transcript (LAT) expression persists in neuronal nuclei. Viral genomes are maintained at an average copy number of 25 per neuron and can be induced to productively replicate by interfering with PI3-Kinase / Akt signaling or the simple withdrawal of nerve growth factor1. A recombinant HSV-1 encoding EGFP fused to the viral lytic protein Us11 provides a functional, real-time marker for replication resulting from reactivation that is readily quantified. In addition to chemical treatments, genetic methodologies such as RNA-interference or gene delivery via lentiviral vectors can be successfully applied to the system permitting mechanistic studies that are very difficult, if not impossible, in animals. In summary, the SCG-based HSV-1 latency / reactivation system provides a powerful, necessary tool to unravel the molecular mechanisms controlling HSV1 latency and reactivation in neurons, a long standing puzzle in virology whose solution may offer fresh insights into developing new therapies that target the latent herpesvirus reservoir.

The protocol describes an efficient and reproducible model system to study herpes simplex virus type 1 (HSV-1) latency and reactivation. The assay employs homogenous sympathetic neuron cultures and allows for the molecular dissection of virus-neuron interactions using a variety of tools including RNA interference and expression of recombinant proteins.

Un sistema de neuronas cultivo primario para el estudio de la latencia del virus del herpes simple y Reactivación

Herpes simplex virus type-1 (HSV-1) establishes a life-long latent infection in peripheral neurons. This latent reservoir is the source of recurrent ...

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Continuous advancements in noninvasive imaging modalities such as magnetic resonance imaging (MRI) have greatly improved our ability to study physiological or pathological processes in living organisms. MRI is also proving to be a valuable tool for capturing transplanted cells in vivo. Initial cell labeling strategies for MRI made use of contrast agents that influence the MR relaxation times (T1, T2, T2*) and lead to an enhancement (T1) or depletion (T2*) of signal where labeled cells are present. T2* enhancement agents such as ultrasmall iron oxide agents (USPIO) have been employed to study cell migration and some have also been approved by the FDA for clinical application. A drawback of T2* agents is the difficulty to distinguish the signal extinction created by the labeled cells from other artifacts such as blood clots, micro bleeds or air bubbles. In this article, we describe an emerging technique for tracking cells in vivo that is based on labeling the cells with fluorine (19F)-rich particles. These particles are prepared by emulsifying perfluorocarbon (PFC) compounds and then used to label cells, which subsequently can be imaged by 19F MRI. Important advantages of PFCs for cell tracking in vivo include (i) the absence of carbon-bound 19F in vivo, which then yields background-free images and complete cell selectivityand(ii) the possibility to quantify the cell signal by 19F MR spectroscopy.

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Tracking of cells using MRI has gained remarkable attention in the past years. This protocol describes the labeling of dendritic cells with fluorine (19F)-rich particles, the in vivo application of these cells, and monitoring the extent of their migration to the draining lymph node with 19F/1H MRI and 19F MRS.

De las Migraciones células dendríticas mediante resonancia 19F / 1H Magnetic

Continuous  advancements in noninvasive imaging modalities such as magnetic resonance  imaging (MRI) have greatly improved our ability to study ...

Lymphocyte Isolation from Human Skin for Phenotypic Analysis and Ex Vivo Cell Culture

Human skin has an important barrier function and contains various immune cells that contribute to tissue homeostasis and protection from pathogens. As the skin is relatively easy to access, it provides an ideal platform to study peripheral immune regulatory mechanisms. Immune resident cells in healthy skin conduct immunosurveillance, but also play an important role in the development of inflammatory skin disorders, such as psoriasis. Despite emerging insights, our understanding of the biology underlying various inflammatory skin diseases is still limited. There is a need for good quality (single) cell populations isolated from biopsied skin samples. So far, isolation procedures have been seriously hampered by a lack of obtaining a sufficient number of viable cells. Isolation and subsequent analysis have also been affected by the loss of immune cell lineage markers, due to the mechanical and chemical stress caused by the current dissociation procedures to obtain single cell suspension. Here, we describe a modified method to isolate T cells from both healthy and involved psoriatic human skin by combining mechanical skin dissociation using an automated tissue dissociator and collagenase treatment. This methodology preserves expression of most immune lineage markers such as CD4, CD8, Foxp3 and CD11c upon the preparation of single cell suspensions. Examples of successful CD4+ T cell isolation and subsequent phenotypic and functional analysis are shown.

Lymphocyte Isolation from Human Skin for Phenotypic Analysis and Ex Vivo Cell Culture

We describe a protocol to efficiently isolate skin resident T cells from human skin biopsies. This protocol yields sufficient numbers of viable human skin resident lymphocytes for flow cytometric analysis and ex vivo culture.

El aislamiento de linfocitos de la piel humana para el Análisis y fenotípica<em&gt; Ex Vivo</em&gt; Cultivo Celular

Human skin has an important barrier function and contains various immune cells that contribute to tissue homeostasis and protection from pathogens. As the ...

Organoids as Model for Infectious Diseases: Culture of Human and Murine Stomach Organoids and Microinjection of Helicobacter Pylori

Recently infection biologists have employed stem cell derived cultures to answer the need for new and better models to study host-pathogen interactions. Three cellular sources have been used: Embryonic stem cells (ESC), induced pluripotent stem cells (iPSC) or adult stem cells. Here, culture of mouse and human gastric organoids derived from adult stem cells is described and used for infection with the gastric pathogen Helicobacter pylori. Human gastric glands are isolated from resection material, seeded in a basement matrix and embedded in medium containing growth factors epidermal growth factor (EGF), R-spondin, Noggin, Wnt, fibroblast growth factor (FGF) 10, gastrin and transforming growth factor (TGF) beta inhibitor. In these conditions, gastric glands grow into 3-dimensional organoids containing 4 lineages of the stomach. The organoids expand indefinitely and can be frozen and thawed similarly as cell lines. For infection studies, bacteria are microinjected into the lumen of the organoids. Infected organoids are processed for imaging. The described methods can be adapted to other organoids and infections with other bacteria, viruses or parasites. This allows the study of infection-induced changes in primary cells.

Stem cell derived cultures harbor tremendous potential to model infectious diseases. Here, the culture of mouse and human gastric organoids derived from adult stem cells is described. The organoids are microinjected with the gastric pathogen Helicobacter pylori.

Organoides como Modelo para Enfermedades Infecciosas: Cultura de Derechos Humanos y organoides estomacales murinos y microinyección de Helicobacter Pylori

Recently infection biologists have employed stem cell derived cultures to answer the need for new and better models to study host-pathogen interactions. ...

Flow Cytometry-based Assay for the Monitoring of NK Cell Functions

Natural killer (NK) cells are an important part of the human tumor immune surveillance system. NK cells are able to distinguish between healthy and virus-infected or malignantly transformed cells due to a set of germline encoded inhibitory and activating receptors. Upon virus or tumor cell recognition a variety of different NK cell functions are initiated including cytotoxicity against the target cell as well as cytokine and chemokine production leading to the activation of other immune cells. It has been demonstrated that accurate NK cell functions are crucial for the treatment outcome of different virus infections and malignant diseases. Here a simple and reliable method is described to analyze different NK cell functions using a flow cytometry-based assay. NK cell functions can be evaluated not only for the whole NK cell population, but also for different NK cell subsets. This technique enables scientists to easily study NK cell functions in healthy donors or patients in order to reveal their impact on different malignancies and to further discover new therapeutic strategies.

A simple and reliable method is described here to analyze a set of NK cell functions such as degranulation, cytokine and chemokine production within different NK cell subsets.

Ensayo de citometría de flujo de base para la supervisión de funciones de las células NK

Natural killer (NK) cells are an important part of the human tumor immune surveillance system. NK cells are able to distinguish between healthy and ...

Mouse- and Human-derived Primary Gastric Epithelial Monolayer Culture for the Study of Regeneration

In vitro studies of gastric wound repair typically involves the use of gastric cancer cell lines in a scratch-wound assay of cellular proliferation and migration. One critical limitation of such assays, however, is their homogenous assortment of cellular types. Repair is a complex process which demands the interaction of several cell types. Therefore, to study a culture devoid of cellular subtypes, is a concern that must be overcome if we are to understand the repair process. The gastric organoid model may alleviate this issue whereby the heterogeneous collection of cell types closely reflects that of the gastric epithelium or other native tissues in vivo. Demonstrated here is a novel, in vitro scratch-wound assay derived from human or mouse 3-dimensional organoids which can then be transferred to a gastric epithelial monolayer as either intact organoids or as a single cell suspension of dissociated organoids. The goal of the protocol is to establish organoid-derived gastric epithelial monolayers that can be used in a novel scratch-wound assay system to study gastric regeneration.

Here we describe a protocol for establishing and culturing human- and mouse-derived 3-dimensional (3D) gastric organoids, and the method for the transfer of 3D organoids to a 2-dimensional monolayer. The use of the gastric epithelial monolayer as a novel scratch-wound assay for regeneration studies is also described.

Cultura de monocapa epitelial gástrico primario derivadas de ratón y humanos para el estudio de la regeneración

In vitro studies of gastric wound repair typically involves the use of gastric cancer cell lines in a scratch-wound assay of cellular proliferation and ...

Bacterial Cell Culture at the Single-cell Level Inside Giant Vesicles

We developed a method for culturing bacterial cells at the single-cell level inside giant vesicles (GVs). Bacterial cell culture is important for understanding the function of bacterial cells in the natural environment. Because of technological advances, various bacterial cell functions can be revealed at the single-cell level inside a confined space. GVs are spherical micro-sized compartments composed of amphiphilic lipid molecules and can hold various materials, including cells. In this study, a single bacterial cell was encapsulated into 10&#8211;30 &#956;m GVs by the droplet transfer method and the GVs containing bacterial cells were immobilized on a supported membrane on a glass substrate. Our method is useful for observing the real-time growth of single bacteria inside GVs. We cultured Escherichia coli (E. coli) cells as a model inside GVs, but this method can be adapted to other cell types. Our method can be used in the science and industrial fields of microbiology, biology, biotechnology, and synthetic biology.

We demonstrate single-cell culture of bacteria inside giant vesicles (GVs). GVs containing bacterial cells were prepared by the droplet transfer method and were immobilized on a supported membrane on a glass substrate for direct observation of bacterial growth. This approach may also be adaptable to other cells.

Cultivo celular bacteriano en el nivel de una sola célula dentro de las vesículas gigantes

We developed a method for culturing bacterial cells at the single-cell level inside giant vesicles (GVs). Bacterial cell culture is important for ...

Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Assay for the Specific and Rapid Detection of Tilapia Lake Virus

Tilapia lake virus disease (TiLVD), an emerging viral disease in tilapia caused by the tilapia lake virus (TiLV), is a persistent challenge in the aquaculture industry that has resulted in the mass morbidity and mortality of tilapia in many parts of the world. An effective, rapid, and accurate diagnostic assay for TiLV infection is therefore necessary to detect the initial infection and to prevent the spread of the disease in aquaculture farming. In this study, a highly sensitive and practical reverse transcription loop-mediated isothermal amplification (RT-LAMP) method is presented to detect tilapia lake virus in fish tissue. A comparison of the RT-qPCR and RT-LAMP assays of infected samples revealed positive results in 63 (100%) and 51 (80.95%) samples, respectively. Moreover, an analysis of uninfected samples showed that all 63 uninfected tissues yielded negative results for both the RT-qPCR and RT-LAMP assays. The cross-reactivity with five pathogens in tilapia was evaluated using RT-LAMP, and all the tests showed negative results. Both the liver and mucus samples obtained from infected fish showed comparable results using the RT-LAMP method, suggesting that mucus can be used in RT-LAMP as a nonlethal assay to avoid killing fish. In conclusion, the results demonstrated that the presented RT-LAMP assay provides an effective method for TiLV detection in tilapia tissue within 1 h. The method is therefore recommended as a screening tool on farms for the rapid diagnosis of TiLV.

Reverse Transcription Loop-Mediated Isothermal Amplification RT-LAMP Assay for the Specific and Rapid Detection of Tilapia Lake Virus

We present an RT-LAMP assay for the detection of TiLV in tilapia fish using simple instruments over a relatively short period of time compared to conventional RT-PCR techniques. This protocol may help control the epidemic spread of TiLVD, especially in developing countries.

Ensayo de amplificación isotérmica mediada por bucle de transcripción inversa (RT-LAMP) para la detección específica y rápida del virus del lago Tilapia

Tilapia lake virus disease (TiLVD), an emerging viral disease in tilapia caused by the tilapia lake virus (TiLV), is a persistent challenge in the ...

P. aeruginosa Infected 3D Co-Culture of Bronchial Epithelial Cells and Macrophages at Air-Liquid Interface for Preclinical Evaluation of Anti-Infectives

fDrug research for the treatment of lung infections is progressing towards predictive in vitro models of high complexity. The multifaceted presence of bacteria in lung models can re-adapt epithelial arrangement, while immune cells coordinate an inflammatory response against the bacteria in the microenvironment. While in vivo models have been the choice for testing new anti-infectives in the context of cystic fibrosis, they still do not accurately mimic the in vivo conditions of such diseases in humans and the treatment outcomes. Complex in vitro models of the infected airways based on human cells (bronchial epithelial and macrophages) and relevant pathogens could bridge this gap and facilitate the translation of new anti-infectives into the clinic. For such purposes, a co-culture model of the human cystic fibrosis bronchial epithelial cell line CFBE41o- and THP-1 monocyte-derived macrophages has been established, mimicking an infection of the human bronchial mucosa by P. aeruginosa at air-liquid interface (ALI) conditions. This model is set up in seven days, and the following parameters are simultaneously assessed: epithelial barrier integrity, macrophage transmigration, bacterial survival, and inflammation. The present protocol describes a robust and reproducible system for evaluating drug efficacy and host responses that could be relevant for discovering new anti-infectives and optimizing their aerosol delivery to the lungs.

P. aeruginosa Infected 3D Co-Culture of Bronchial Epithelial Cells and Macrophages at Air-Liquid Interface for Preclinical Evaluation of Anti-Infectives

We describe a protocol for a three-dimensional co-culture model of infected airways, using CFBE41o- cells, THP-1 macrophages, and Pseudomonas aeruginosa, established at the air-liquid interface. This model provides a new platform to simultaneously test antibiotic efficacy, epithelial barrier function, and inflammatory markers.

P. aeruginosa Co-cultivo 3D infectado de células epiteliales bronquiales y macrófagos en la interfaz aire-líquido para la evaluación preclínica de los antiinfecciosos

fDrug research for the treatment of lung infections is progressing towards predictive in vitro models of high complexity. The multifaceted presence of ...