Los autores desean agradecer a las siguientes fuentes de financiación: Canadiense Institutos de Investigación en Salud (CIHR), las Ciencias Naturales e Ingeniería de Investigación (NSERC).

1. Desarrollo del programa de LabVIEW <ol><li> Un controlador de flujo másico (MKS M100B misa-Flo Controlador) está unido a la línea de gas de helio para garantizar una velocidad de flujo de gas precisa. Esta unidad es controlada por una tensión de entrada, que oscila entre 0 y 5 V. Un bucle de control en el programa LabView determina el voltaje requerido en cualquier momento dado. Interfaz entre el ordenador y el controlador de flujo de masa se lleva a cabo por un dispositivo de adquisición de datos (NI USB-6009), y una fuente de alimentación de 12 V suministra potencia al controlador de flujo másico. </li><li> Dos diapositivas lineal de posicionamiento se utilizan para controlar el movimiento de la placa de 6 pocillos, una para cada dirección. Cada conjunto se compone de una serie MA15-Velmex Asamblea Unislide junto con un motor paso a paso, y ambos conjuntos están controlados por un único Velmex VXM Stepping Motor Controller. El controlador permite para hacer footing manual de cada motor o acepta una cadena de comandos en serie externos, la combinación de los cuales permitir el movimiento específico patterns. Varios patrones se pueden programar en el programa LabView, que requiere que el usuario proporcione sólo la velocidad de la antorcha deseado, así como las dimensiones de ruta. </li></ol> 2. Preparación de Equipo <ol><li> Abra tanto el cilindro de helio y el regulador. </li><li> Encienda el controlador del motor. </li><li> Abra el programa LabView y verificar todas las condiciones. </li><li> Asegúrese de que la plataforma esté centrada. Para comprobarlo, busque en cada etapa del motor y verificar que cada carro no está cerca de cualquier extremo escenario. Ya sea que el centro del programa de los carros o ajuste manualmente mediante los controles de correr en la parte frontal del controlador de motor. </li><li> Si esta es la primera carrera del día, se recomienda ejecutar el programa una vez y sin células, para asegurar la instalación funciona correctamente. </li></ol> 3. Preparación de la Altura Gas Jet boquilla capilar <ol><li> Quite la capilaridad del soporte y cero el dial de altura. </li><li> Coloque la placa de 6 pocillos on la plataforma. </li><li> Vuelva a colocar y bajar el capilar chorro de gas a la parte inferior del pozo hasta que llega a la hoja de la cubierta. Fije el capilar en el soporte. </li><li> Utilización del dial de altura, levante el capilar 3 mm. Marque esta altura en la base del capilar. </li><li> Levante el capilar a una altura segura y luego retire la placa de 6 pocillos. </li></ol> 4. Celular Protocolo Permeabilización <ol><li> Cultura línea celular adherente a la confluencia de la cubierta de cristal se desliza en una placa de 6 pocillos usando técnicas estándar de cultivo. Para las células HeLa, semillas placas de 6 pocillos con 2 x 10 5 células por pocillo y se incuban durante 48 horas antes del tratamiento. </li><li> Preparar volumen apropiado de solución que contiene el vector deseado. Para hrGFPII-1, una concentración de 50 ng / l en 1x PBS proporciona una señal fluorescente fuerte en células HeLa 24 horas después de la transfección. Para los estudios de dextrano, se recomienda 80 mg / ml de 10 kDa de dextrano fluorescente verde. De ahora en adelante, esta solución será referido a un&quot;La solución vector&quot; s. </li><li> Retire el medio de cultivo de células de bien y enjuáguese la boca tres veces con PBS 1x. </li><li> Pipetear 1.370 l de solución de vector preparado en el paso 4.2 en el pozo. Esto debería dar lugar a una profundidad de líquido de aproximadamente 1,3 mm. </li><li> Coloque el pocillo que contiene la solución del vector en el centro de la plataforma. Baje la boquilla de chorro de gas al nivel previamente marcado que indica una altura de boquilla de 3 mm por encima de la diapositiva. </li><li> Establecer velocidad de flujo de helio en el programa LabView y seleccionar el patrón de movimiento deseado para ser utilizado. Seleccione &quot;Ejecutar&quot; cuando esté listo para comenzar el protocolo de permeabilización. Habrá un período de retraso inicial en que el controlador de flujo de masa se está preparando para dar el caudal necesario. Una vez que se ha alcanzado la velocidad de flujo apropiada, el programa LabView activará los motores paso a paso para mover el bien en el patrón de permeabilización deseada. Una vez que la plataforma se ha detenido, espere aproximadamente 30 segundos y retirar la solución del vector.Nota: permeabilización óptimo se produce cerca de una presión dinámica de 100 hasta 200 Pa a la salida de la boquilla, en función del diámetro capilar. </li><li> Lavar tres veces con PBS 1x. </li><li> Llenar bien con medios de cultivo fresco. </li><li> Repita los pasos 4.3 a 4.6 para el número deseado de experimentos. Nota: Asegúrese de incluir muestras de control que consisten en pozos están llenos de la solución vector sin el chorro de gas que se ejecute sobre ellos. Agregar la solución en los pocillos de control durante aproximadamente 1 min continúe en los pasos 4.5 y 4.6. </li><li> Si la ejecución de un experimento de transfección hrGFP, devuelva la placa de 6 pocillos a la incubadora durante 24 horas para permitir que el material transfectadas para ser transcrito por las células. Si al ejecutar un experimento de permeabilización dextrano, volver placa de 6 pocillos a la incubadora durante 15 min. </li></ol> 5. Imágenes de células <ol><li> Si lo desea, inmediatamente antes de la imagen, counterstain con mancha en vivo / muerto apropiado para evaluar la muerte celular. </li><li> Celdas de imagen con appropmicroscopio riate para investigar la eficacia de transfección / permeabilización. </li></ol>

<ol>
	<li>Rosenberg, S. A., 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=Gene+transfer+into+humans--immunotherapy+of+patients+with+advanced+melanoma,+using+tumor-infiltrating+lymphocytes+modified+by+retroviral+gene+transduction.">Gene transfer into humans--immunotherapy of patients with advanced melanoma, using tumor-infiltrating lymphocytes modified by retroviral gene transduction.</a> The New England Journal of Medicine. 323, 570-578 (1990).</li><li>Yang, 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=Cellular+immunity+to+viral+antigens+limits+E1-deleted+adenoviruses+for+gene+therapy.">Cellular immunity to viral antigens limits E1-deleted adenoviruses for gene therapy.</a> Proceedings of the National Academy of Sciences of the United States of America. 91, 4407-4411 (1994).</li><li>Chen, C., Okayama, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-efficiency+transformation+of+mammalian+cells+by+plasmid+DNA.">High-efficiency transformation of mammalian cells by plasmid DNA.</a> Molecular and cellular biology. 7, 2745-2752 (1987).</li><li>Walev, I., 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=Delivery+of+proteins+into+living+cells+by+reversible+membrane+permeabilization+with+streptolysin-O.">Delivery of proteins into living cells by reversible membrane permeabilization with streptolysin-O.</a> Proceedings of the National Academy of Sciences of the United States of America. 98, 3185-3190 (2001).</li><li>Felgner, P. 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=Lipofection:+a+highly+efficient,+lipid-mediated+DNA-transfection+procedure.">Lipofection: a highly efficient, lipid-mediated DNA-transfection procedure.</a> Proceedings of the National Academy of Sciences of the United States of America. 84, 7413-7417 (1987).</li><li>Hamm, A., Krott, N., Breibach, I., Blindt, R., Bosserhoff, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+transfection+method+for+primary+cells.">Efficient transfection method for primary cells.</a> Tissue engineering. 8, 235-245 (2002).</li><li>Rauth, S., Kucherlapati, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+DNA+Transferred+into+Mammalian-Cells.">Expression of DNA Transferred into Mammalian-Cells.</a> J. Bioscience. 6, 543-567 (1984).</li><li>Spandidos, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electric+field-mediated+gene+transfer+(electroporation)+into+mouse+Friend+and+human+K562+erythroleukemic+cells.">Electric field-mediated gene transfer (electroporation) into mouse Friend and human K562 erythroleukemic cells.</a> Gene analysis techniques. 4, 50-56 (1987).</li><li>Chu, G., Hayakawa, H., Berg, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroporation+for+the+efficient+transfection+of+mammalian+cells+with+DNA.">Electroporation for the efficient transfection of mammalian cells with DNA.</a> Nucleic Acids Research. 15, 1311-1326 (1987).</li><li>Fechheimer, M., 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=Transfection+of+mammalian+cells+with+plasmid+DNA+by+scrape+loading+and+sonication+loading.">Transfection of mammalian cells with plasmid DNA by scrape loading and sonication loading.</a> Proceedings of the National Academy of Sciences of the United States of America. 84, 8463-8467 (1987).</li><li>Koch, S., Pohl, P., Cobet, U., Rainov, N. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasound+enhancement+of+liposome-mediated+cell+transfection+is+caused+by+cavitation+effects.">Ultrasound enhancement of liposome-mediated cell transfection is caused by cavitation effects.</a> Ultrasound in Medicine &amp; Biology. 26, 897-903 (2000).</li><li>Greenleaf, W. J., Bolander, M. E., Sarkar, G., Goldring, M. B., Greenleaf, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Artificial+cavitation+nuclei+significantly+enhance+acoustically+induced+cell+transfection.">Artificial cavitation nuclei significantly enhance acoustically induced cell transfection.</a> Ultrasound in Medicine &amp; Biology. 24, 587-595 (1998).</li><li>Yang, N. S., Burkholder, J., Roberts, B., Martinell, B., McCabe, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+and+in+vitro+gene+transfer+to+mammalian+somatic+cells+by+particle+bombardment.">In vivo and in vitro gene transfer to mammalian somatic cells by particle bombardment.</a> Proceedings of the National Academy of Sciences of the United States of America. 87, 9568-9572 (1990).</li><li>Hallow, D. M., 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=Shear-induced+intracellular+loading+of+cells+with+molecules+by+controlled+microfluidics.">Shear-induced intracellular loading of cells with molecules by controlled microfluidics.</a> Biotechnology and Bioengineering. 99, 846-854 (2008).</li><li>Chouinard-Pelletier, G. L., Guay, M., Coulombe, D., Leask, S., L, R., Jones, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+inert+gas+jets+to+measure+the+forces+required+for+mechanical+gene+transfection.">Use of inert gas jets to measure the forces required for mechanical gene transfection.</a> Biomedical Engineering Online. 11, (2012).</li><li>Leduc, M., Coulombe, S., Leask, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atmospheric+Pressure+Plasma+Jet+Deposition+of+Patterned+Polymer+Films+for+Cell+Culture+Applications.">Atmospheric Pressure Plasma Jet Deposition of Patterned Polymer Films for Cell Culture Applications.</a> Ieee T. Plasma Sci. 37, 927-933 (2009).</li><li>Lu, H., 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=Microfluidic+shear+devices+for+quantitative+analysis+of+cell+adhesion.">Microfluidic shear devices for quantitative analysis of cell adhesion.</a> Analytical Chemistry. 76, 5257-5264 (2004).</li><li>Sankin, G. N., Yuan, F., Zhong, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsating+tandem+microbubble+for+localized+and+directional+single-cell+membrane+poration.">Pulsating tandem microbubble for localized and directional single-cell membrane poration.</a> Physical Review Letters. 105, 078101 (2010).</li></ol>

Los autores declaran que no tienen intereses financieros en competencia.

Permeabilización chorro de gas inerte es una técnica útil para la transfección de células adherentes. Se proporciona la capacidad de transferir biomoléculas en células con el uso de fuerzas mecánicas, lo que elimina la necesidad de productos químicos potencialmente dañinos o vectores virales. La técnica podría potencialmente dar a los investigadores y los clínicos de una manera eficiente y relativamente sencillo para transfectar células con precisión. La selectividad de la permeabilización también es ú...

Con la evolución de la biomedicina y la comprensión de la mecánica de células, la entrega de las biomoléculas en células se ha convertido en vital para muchos campos de investigación y las terapias médicas. Diferentes técnicas han sido desarrollados para introducir moléculas extrañas a través de la membrana plasmática y en el citosol de la célula. Estos se pueden clasificar en general ya sea como: técnicas viral, químicos o mecánicos. Técnicas virales pueden transfectar material genético, tales como ARN y ADN utilizando vectores virales 1. Técnicas virales tienden a tener altos rendimientos en ciertas líneas celulares, sin embargo tienen la posibilidad de reacciones inmunes e inflamatorias 2. Métodos de transfección química comunes incluyen precipitación con fosfato de calcio 3, exotoxinas bacterianas 4 y 5 lipofección. Estas técnicas han demostrado ser eficaces, sin embargo, ciertos problemas surgen tales como toxicidad celular y no especificidad. Además, las técnicas tales como Phosphat de calcioe precipitación se han encontrado para tener eficiencias de transfección de hasta 70%, pero sólo en ciertas líneas celulares, rara vez en las células primarias 6. Esto es de nota como el aumento de los esfuerzos de investigación se están poniendo en células primarias, especialmente en el caso de diseñar diversos tratamientos para el uso clínico y el estudio de funcionamiento de ADN. La interrupción temporal de la membrana celular a través de estímulos mecánica es una alternativa para la introducción de moléculas extrañas en las células. Las técnicas incluyen: la microinyección de moléculas 7, electroporación usando un campo eléctrico para romper la membrana 8,9, sonoporación utilizando ondas de ultrasonido para romper la membrana celular 10-12, bombardeo de partículas como se demuestra por la &quot;pistola de genes&quot;, que dispara partículas unidas con genes en la célula 13, y, más recientemente, la aplicación de la tensión de cizallamiento de fluido que se ha demostrado para permeabilizar temporalmente las células de mamífero 14,15. Aunque mecánicométodos cols evitar algunos de los problemas antes mencionados, por lo general son acompañados por una menor eficiencia y configuraciones muy complejas y especializadas. Una antorcha de descarga luminiscente a presión atmosférica (APGD-t) fue desarrollado en McGill con el objetivo inicial de la funcionalización de superficies y separar las células adherentes in vitro 16. Casualmente, se descubrió que una mancha en vivo / muerto se está utilizando de alguna manera se está tomada en por las células sin que se añade un agente de permeabilización. Además, este parecía haber ocurrido sólo en áreas restringidas de los pozos que sucedieron para que coincida con la ruta de la antorcha. Investigación de las capacidades de permeabilización de la APGD-t continuó y en los estudios de control, se encontró que el chorro de gas inerte portador del plasma sin excitación también fue capaz de permeabilizar las células. Esto contradecía la hipótesis inicial de que las especies reactivas creadas por el chorro de plasma alterado de forma temporal la función de la membrana, y sugirió que simplemente los mecánicosfuerzas de cal fueron suficientes para causar la permeabilización celular. A partir de aquí, se continuaron los estudios en nuestro laboratorio para tratar de cuantificar y caracterizar la eficiencia de la permeabilización de un chorro de gas inerte, así como cuidar a sus capacidades de transfección 16. A través de estos estudios, se ha encontrado que los microporos se puede hacer en forma de hecho en la membrana plasmática, y estos poros tienden a cerrar de nuevo dentro de aproximadamente 5 seg 15. Hemos demostrado la utilidad de la técnica in vitro e in vivo en la membrana corioalantoidea de un embrión de pollo.

<table border="1">
	<tbody>
		<tr>
			<td>Vitality hrGFPII-1</td>
			<td>Agilent Technologies Canada</td>
			<td>240143-57</td>
			<td>Green fluorescent protein for transfection experiments on HeLa cells</td>
		</tr>
		<tr>
			<td>Dextran, AlexaFluor 488; 10,000 MW, Anionic, Fixable</td>
			<td>Life Technologies Inc.</td>
			<td>D22910</td>
			<td>dextran for permeabilization experiments</td>
		</tr>
		<tr>
			<td>LIVE/DEAD Viability/Cytotoxicity Kit</td>
			<td>Life Technologies Inc.</td>
			<td>L3224</td>
			<td>for counterstaining of mammalian cells</td>
		</tr>
		<tr>
			<td>Prolong Gold Antifade Reagent</td>
			<td>Invitrogen</td>
			<td>P36930</td>
			<td>for mounting slides when imaging</td>
		</tr>
		<tr>
			<td>Ultra High Purity Helium</td>
			<td>Praxair Canada Inc.</td>
			<td>HE 5.0UH-T</td>
			<td></td>
		</tr>
		<tr>
			<td>Hyclone DMEM/ High Glucose Media - 500 ml</td>
			<td>Thermo Scientific</td>
			<td>SH30022.01</td>
			<td>for HeLa cells</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Invitrogen</td>
			<td>26140079</td>
			<td>For DMEM media</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin, liquid</td>
			<td>Invitrogen</td>
			<td>15140-122</td>
			<td>For DMEM media</td>
		</tr>
		<tr>
			<td>Phosphate-Buffered Saline (PBS) 1x</td>
			<td></td>
			<td></td>
			<td>Produced in lab</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Table 1. List of required reagents</td>
		</tr>
		<tr>
			<td>6-Well Clear TC-Treated Microplates</td>
			<td>Corning</td>
			<td>3506</td>
			<td></td>
		</tr>
		<tr>
			<td>#1 22 x 22 Coverslips</td>
			<td>Fisher</td>
			<td>12-542B</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Capillaries</td>
			<td>World Precision Instruments</td>
			<td></td>
			<td>WPI Sizing Information</td>
		</tr>
		<tr>
			<td>ID (mm): 1, 0.86, 0.68, 0.5 Order #: 1B200, 1B150, 1B120, 1B100</td>
		</tr>
		<tr>
			<td>Mass-Flo Controller</td>
			<td>MKS</td>
			<td>M100B01314CS1BV</td>
			<td>Mass flow controller, Series M100B, requires an external 12 V power supply</td>
		</tr>
		<tr>
			<td>USB-6009 DAQ Device</td>
			<td>National Instruments</td>
			<td>779026-01</td>
			<td></td>
		</tr>
		<tr>
			<td>UniSlide Assembly with stepping motor and controller</td>
			<td>Velmex</td>
			<td></td>
			<td>Two series MA15 UniSlide Assemblies, fitted with Vexta 1.8&#176; stepping motors provided by Velmex, and controlled by a VXM Stepping Motor Controller</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Table 2. List of required equipment</td>
		</tr>
	</tbody>
</table>

permeabilization of adhered cells using an inert gas jet

Existen diversas técnicas de transfección de células y éstas se pueden dividir tres grandes categorías: viral, químicas y mecánicas. Este protocolo describe un método mecánico para permeabilizar temporalmente las células adherentes utilizando un chorro de gas inerte que puede facilitar la transferencia de macromoléculas normalmente no permeables a las células. Creemos que esta técnica funciona impartiendo fuerzas de cizallamiento en la membrana plasmática de las células adherentes, resultando en la formación temporal de microporos. Una vez que se crean estos poros, las células son entonces permeable al material genético y otras biomoléculas. Las fuerzas mecánicas que intervienen no corren el riesgo de dañar permanentemente las células o se separe de su sustrato. No es, por lo tanto, una estrecha gama de dinámica de gases inertes donde la técnica es eficaz. Un chorro de gas inerte se ha demostrado su eficacia en la permeabilización de diversas líneas de células adherentes, incluidos HeLa, HEK293 y células endoteliales de aorta abdominal humanos. Este protocolo es apropiado para el permeabilization de células adherentes, tanto in vitro y, como hemos demostrado, in vivo, demostrando que puede ser utilizado para la investigación y, potencialmente, en futuras aplicaciones clínicas. También tiene la ventaja de permeabilización de las células de una manera espacialmente restrictiva, lo que podría llegar a ser una valiosa herramienta de investigación.

La permeabilización de las células HeLa con 10 kDa de dextrano fluorescente verde usando un chorro de gas helio con un capilar de diámetro interior 0,86 mm se muestra en la Figura 1. Las células fueron counterstained inmediatamente después de la permeabilización con 2 l / ml EthD-1 solución (LIVE / DEAD viabilidad / citotoxicidad Kit) para visualizar la muerte celular. Inmediatamente después de la contratinción, cubreobjetos fueron montados y la imagen. Esta figura muestra los resultados de eje...

Watch this Scientific Journal Video about Permeabilization of Adhered Cells Using an Inert Gas Jet at JoVE.com

Permeabilization of Adhered Cells Using an Inert Gas Jet

Este protocolo describe un método para la permeabilización temporal de células adherentes utilizando un chorro de gas inerte. Esta técnica facilita la transferencia de material genético y biomoléculas en células de mamífero adherentes por la utilización de fuerzas mecánicas para romper la membrana de plasma.

Permeabilización de células adheridas Usando un gas inerte Jet

Various cell transfection techniques exist and these can be broken down to three broad categories: viral, chemical and mechanical. This protocol describes ...

permeabilization-of-adhered-cells-using-an-inert-gas-jet

Research

JoVE Journal

Bioengineering

9.6K vistas.  McGill University.  Este protocolo describe un método para la permeabilización temporal de células adherentes utilizando un chorro de gas inerte. Esta técnica facilita la transferencia de material genético y biomoléculas en células de mamífero adherentes por la utilización de fuerzas mecánicas para romper la membrana de plasma. 

Video: Permeabilization of Adhered Cells Using an Inert Gas Jet

An Experimental System to Study Mechanotransduction in Fetal Lung Cells

Mechanical forces generated in utero by repetitive breathing-like movements and by fluid distension are critical for normal lung development. A key component of lung development is the differentiation of alveolar type II epithelial cells, the major source of pulmonary surfactant. These cells also participate in fluid homeostasis in the alveolar lumen, host defense, and injury repair. In addition, distal lung parenchyma cells can be directly exposed to exaggerated stretch during mechanical ventilation after birth. However, the precise molecular and cellular mechanisms by which lung cells sense mechanical stimuli to influence lung development and to promote lung injury are not completely understood. Here, we provide a simple and high purity method to isolate type II cells and fibroblasts from rodent fetal lungs. Then, we describe an in vitro system, The Flexcell Strain Unit, to provide mechanical stimulation to fetal cells, simulating mechanical forces in fetal lung development or lung injury. This experimental system provides an excellent tool to investigate molecular and cellular mechanisms in fetal lung cells exposed to stretch. Using this approach, our laboratory has identified several receptors and signaling proteins that participate in mechanotransduction in fetal lung development and lung injury.

Mechanical forces play a key role in lung development and lung injury. Here, we describe a method to isolate rodent fetal lung type II epithelial cells and fibroblasts and to expose them to mechanical stimulation using an in vitro system.

Un sistema experimental para estudiar Mecanotransducción en células de pulmón fetal

Mechanical forces generated in utero by repetitive breathing-like movements and by fluid distension are critical for normal lung development. A key ...

Investigación

Bioingeniería

Transplantation of Induced Pluripotent Stem Cell-derived Mesoangioblast-like Myogenic Progenitors in Mouse Models of Muscle Regeneration

Patient-derived iPSCs could be an invaluable source of cells for future autologous cell therapy protocols. iPSC-derived myogenic stem/progenitor cells similar to pericyte-derived mesoangioblasts (iPSC-derived mesoangioblast-like stem/progenitor cells: IDEMs) can be established from iPSCs generated from patients affected by different forms of muscular dystrophy. Patient-specific IDEMs can be genetically corrected with different strategies (e.g. lentiviral vectors, human artificial chromosomes) and enhanced in their myogenic differentiation potential upon overexpression of the myogenesis regulator MyoD. This myogenic potential is then assessed in vitro with specific differentiation assays and analyzed by immunofluorescence. The regenerative potential of IDEMs is further evaluated in vivo, upon intramuscular and intra-arterial transplantation in two representative mouse models displaying acute and chronic muscle regeneration. The contribution of IDEMs to the host skeletal muscle is then confirmed by different functional tests in transplanted mice. In particular, the amelioration of the motor capacity of the animals is studied with treadmill tests. Cell engraftment and differentiation are then assessed by a number of histological and immunofluorescence assays on transplanted muscles. Overall, this paper describes the assays and tools currently utilized to evaluate the differentiation capacity of IDEMs, focusing on the transplantation methods and subsequent outcome measures to analyze the efficacy of cell transplantation.

Induced pluripotent stem cell (iPSC)-derived myogenic progenitors are promising candidates for cell therapy strategies to treat muscular dystrophies. This protocol describes transplantation and functional measurements required to evaluate the engraftment and differentiation of iPSC-derived mesoangioblasts (a type of muscle progenitors) in mouse models of acute and chronic muscle regeneration.

Trasplante De InducidaS Pluripotentes Derivadas De Células Madre Mesoangioblastos Como Progenitores Miógenos En Modelos De Ratón De La Regeneración Muscular

Patient-derived iPSCs could be an invaluable source of cells for future autologous cell therapy protocols. iPSC-derived myogenic stem/progenitor cells ...

Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

A two-dimensional gas chromatography-time-of-flight mass spectrometry method is described for characterization of the aqueous fraction of bio-crude produced from hydrothermal liquefaction of algae. This protocol can also be employed to analyze the aqueous fraction of liquid products from fast pyrolysis, catalytic fast pyrolysis, catalytic deoxygenation and hydro-treating.

Caracterización cualitativa de la fracción acuosa de hidrotérmico Licuefacción de algas mediante 2D cromatografía de gases con espectrometría de masas de tiempo de vuelo

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in ...

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

Accurately detecting and counting sparse bacterial samples has many applications in the food, beverage, and pharmaceutical processing industries, in medical diagnostics, and for life detection by robotic missions to other planets and moons of the solar system. Currently, sparse bacterial samples are counted by culture plating or epifluorescence microscopy. Culture plates require long incubation times (days to weeks), and epifluorescence microscopy requires extensive staining and concentration of the sample. Here, we demonstrate how to use off-axis digital holographic microscopy (DHM) to enumerate bacteria in very dilute cultures (100-104 cells/mL). First, the construction of the custom DHM is discussed, along with detailed instructions on building a low-cost instrument. The principles of holography are discussed, and a statistical model is used to estimate how long videos should be to detect cells, based on the optical performance characteristics of the instrument and the concentration of the bacterial solution (Table 2). Video detection of cells at 105, 104, 103, and 100 cells/mL is demonstrated in real time using un-reconstructed holograms. Reconstruction of amplitude and phase images is demonstrated using an open-source software package.

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy DHM

Digital holographic microscopy (DHM) is a volumetric technique that allows imaging samples 50-100X thicker than brightfield microscopy at comparable resolution, with focusing performed post-processing. Here DHM is used for identifying, counting, and tracking microorganisms at very low densities and compared with optical density measurements, plate count, and direct count.

Cuantificación de microorganismos a bajas concentraciones usando microscopia holográfica Digital (DHM)

Accurately detecting and counting sparse bacterial samples has many applications in the food, beverage, and pharmaceutical processing industries, in ...

High-resolution Patterning Using Two Modes of Electrohydrodynamic Jet: Drop on Demand and Near-field Electrospinning

Electrohydrodynamic (EHD) jet printing has drawn attention in various fields because it can be used as a high-resolution and low-cost direct patterning tool. EHD printing uses a fluidic supplier to maintain the extruded meniscus by pushing the ink out of the nozzle tip. The electric field is then used to pull the meniscus down to the substrate to produce high-resolution patterns. Two modes of EHD printing have been used for fine patterning: continuous near-field electrospinning (NFES) and dot-based drop-on-demand (DOD) EHD printing. According to the printing modes, the requirements for the printing equipment and ink viscosity will differ. Even though two different modes can be implemented with a single EHD printer, the realization methods significantly differ in terms of ink, fluidic system, and driving voltage. Consequently, without a proper understanding of the jetting requirements and limitations, it is difficult to obtain the desired results. The purpose of this paper is to present a guideline so that inexperienced researchers can reduce the trial and error efforts to use the EHD jet for their specific research and development purposes. To demonstrate the fine-patterning implementation, we use Ag nanoparticle ink for the conductive patterning in the protocol. In addition, we also present the generalized printing guidelines that can be used for other types of ink for various fine-patterning applications.

Here, we present a protocol to produce high-resolution conductive patterns using electrohydrodynamic (EHD) jet printing. The protocol includes two modes of EHD jet printing: the continuous near-field electrospinning (NFES) and the dot-based drop-on-demand (DOD) EHD printing.

Alta resolución patrones usando dos modos de electrohidrodinámicos Jet: caída en la demanda y Electrospinning de campo cercano

Electrohydrodynamic (EHD) jet printing has drawn attention in various fields because it can be used as a high-resolution and low-cost direct patterning ...

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver engineering, including in vivo organ decellularization followed by repopulation, has emerged as a promising approach over ex vivo liver engineering. However, postoperative survival was not achieved. The aim of this study is to develop a novel surgical technique of in vivo selective liver lobe perfusion in rats as a prerequisite for in vivo liver engineering. We generate a circuit bypass only through the left lateral lobe. Then, the left lateral lobe is perfused with heparinized saline. The experiment is performed with 4 groups (n = 3 rats per group) based on different perfusion times of 20 min, 2 h, 3 h, and 4 h. Survival, as well as the macroscopically visible change of color and the histologically determined absence of blood cells in the portal triad and the sinusoids, is taken as an indicator for a successful model establishment. After selective perfusion of the left lateral lobe, we observe that the left lateral lobe, indeed, turned from red to faint yellow. In a histological assessment, no blood cells are visible in the branch of the portal vein, the central vein, and the sinusoids. The left lateral lobe turns red after reopening the blocked vessels. 12/12 rats survived the procedure for more than one week. We are the first to report a surgical model for in vivo single liver lobe perfusion with a long survival period of more than one week. In contrast to the previously published report, the most important advantage of the technique presented here is that perfusion of 70% of the liver is maintained throughout the whole procedure. The establishment of this technique provides a foundation for in vivo partial liver engineering in rats, including decellularization and recellularization.

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

We establish a novel surgical technique for an in vivo single liver lobe perfusion model in rat as a prerequisite for further studying in vivo partial liver engineering in the future.

Una novedosa técnica quirúrgica como base para In Vivo parcial ingeniería hígado de rata

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver ...

Purification and Analytics of a Monoclonal Antibody from Chinese Hamster Ovary Cells Using an Automated Microbioreactor System

Monoclonal antibodies (mAbs) are one of the most popular and well-characterized biological products manufactured today. Most commonly produced using Chinese hamster ovary (CHO) cells, culture and process conditions must be optimized to maximize antibody titers and achieve target quality profiles. Typically, this optimization uses automated microscale bioreactors (15 mL) to screen multiple process conditions in parallel. Optimization criteria include culture performance and the critical quality attributes (CQAs) of the monoclonal antibody (mAb) product, which may impact its efficacy and safety. Culture performance metrics include cell growth and nutrient consumption, while the CQAs include the mAb's N-glycosylation and aggregation profiles, charge variants, and molecular weight. This detailed protocol describes how to purify and subsequently analyze HCCF samples produced by an automated microbioreactor system to gain valuable performance metrics and outputs. First, an automated protein A fast protein liquid chromatography (FPLC) method is used to purify the mAb from harvested cell culture samples. Once concentrated, the glycan profiles are analyzed by mass spectrometry using a specific platform (refer to the Table of Materials). Antibody molecular weights and aggregation profiles are determined using size exclusion chromatography-multiple angle light scattering (SEC-MALS), while charge variants are analyzed using microchip capillary zone electrophoresis (mCZE). In addition to the culture performance metrics captured during the bioreactor process (i.e., culture viability, cell counts, and common metabolites including glutamine, glucose, lactate, and ammonia), spent media is analyzed to identify limiting nutrients to improve the feeding strategies and overall process design. Therefore, a detailed protocol for the absolute quantification of amino acids by liquid chromatography-mass spectrometry (LC-MS) of spent media is also described. The methods used in this protocol take advantage of high-throughput platforms that are compatible for large numbers of small-volume samples.

A detailed protocol for the purification and subsequent analysis of a monoclonal antibody from harvested cell culture fluid (HCCF) of automated microbioreactors has been described. Use of analytics to determine critical quality attributes (CQAs) and maximizing limited sample volume to extract vital information is also presented.

Purificación y análisis de un anticuerpo monoclonal de células de ovario de hámster chino utilizando un sistema automatizado de microbiorreactores

Monoclonal antibodies (mAbs) are one of the most popular and well-characterized biological products manufactured today. Most commonly produced using ...

Screening and Identification of Small Peptides Targeting Fibroblast Growth Factor Receptor2 using a Phage Display Peptide Library

The human Fibroblast Growth Factor Receptor (FGFR) family comprises four members, namely, FGFR1, FGFR2, FGFR3, and FGFR4, that are involved in various biological activities including cell proliferation, survival, migration and differentiation. Several aberrations in the FGFR signaling pathway, owing to mutations or gene amplification events, have been identified in various types of cancers. Hence, recent research has focused on developing strategies involving therapeutic targeting of FGFRs. Current FGFR inhibitors at various stages of pre-clinical and clinical development include either small molecule inhibitors of tyrosine kinases or monoclonal antibodies, with only a few peptide- based inhibitors in the pipeline. Here, we provide a protocol using phage display technology to screen small peptides as antagonists of FGFR2. Briefly, a library of phage-displayed peptides was incubated in a plate coated with FGFR2. Subsequently, unbound phage was washed off by TBST (TBS + 0.1% [v/v] Tween-20), and bound phage was eluted with 0.2 M glycine-HCl buffer (pH 2.2). The eluted phage was further amplified and used as input for the next round of biopanning. Following three rounds of biopanning, the peptide sequences of individual phage clones were identified by DNA sequencing. Finally, the screened peptides were synthesized and analyzed for affinity and biological activity.

Herein, we present a detailed protocol for screening small peptides that bind to FGFR2 using a phage display peptide library. We further analyze the affinity of the selected peptides toward FGFR2 in vitro and its ability to suppress cell proliferation.

Detección e identificación de pequeños péptidos dirigidos al receptor de factor de crecimiento de fibroblastos2 utilizando una biblioteca de péptidos de pantalla de fago

The human Fibroblast Growth Factor Receptor (FGFR) family comprises four members, namely, FGFR1, FGFR2, FGFR3, and FGFR4, that are involved in various ...

The Fabrication and Operation of a Continuous Flow, Micro-Electroporation System with Permeabilization Detection

Current therapeutic innovations, such as CAR-T cell therapy, are heavily reliant on viral-mediated gene delivery. Although efficient, this technique is accompanied by high manufacturing costs, which has brought about an interest in using alternative methods for gene delivery. Electroporation is an electro-physical, non-viral approach for the intracellular delivery of genes and other exogenous materials. Upon the application of an electric field, the cell membrane temporarily allows molecular delivery into the cell. Typically, electroporation is performed on the macroscale to process large numbers of cells. However, this approach requires extensive empirical protocol development, which is costly when working with primary and difficult-to-transfect cell types. Lengthy protocol development, coupled with the requirement of large voltages to achieve sufficient electric-field strengths to permeabilize the cells, has led to the development of micro-scale electroporation devices. These micro-electroporation devices are manufactured using common microfabrication techniques and allow for greater experimental control with the potential to maintain high throughput capabilities. This work builds off a microfluidic-electroporation technology capable of detecting the level of cell membrane permeabilization at a single-cell level under continuous flow. However, this technology was limited to 4 cells processed per second, and thus a new approach for increasing the system throughput is proposed and presented here. This new technique, denoted as cell-population-based feedback control, considers the cell permeabilization response to a variety of electroporation pulsing conditions and determines the best-suited electroporation pulse conditions for the cell type under test. A higher-throughput mode is then used, where this 'optimal' pulse is applied to the cell suspension in transit. The steps for fabricating the device, setting up and running the microfluidic experiments, and analyzing the results are presented in detail. Finally, this micro-electroporation technology is demonstrated by delivering a DNA plasmid encoding for green fluorescent protein (GFP) into HEK293 cells.

This protocol describes the microfabrication techniques required to build a lab-on-a-chip, microfluidic electroporation device. The experimental setup performs controlled, single-cell-level transfections in a continuous flow and can be extended to higher throughputs with population-based control. An analysis is provided showcasing the ability to electrically monitor the degree of cell membrane permeabilization in real-time.

La fabricación y operación de un sistema de microelectroporación de flujo continuo con detección de permeabilización

Current therapeutic innovations, such as CAR-T cell therapy, are heavily reliant on viral-mediated gene delivery. Although efficient, this technique is ...

Formulating and Characterizing an Exosome-based Dopamine Carrier System

Exosomes between 40 and 200 nm in size constitute the smallest subgroup of extracellular vesicles. These bioactive vesicles secreted by cells play an active role in intercellular cargo and communication. Exosomes are mostly found in body fluids such as plasma, cerebrospinal fluid, urine, saliva, amniotic fluid, colostrum, breast milk, joint fluid, semen, and pleural acid. Considering the size of exosomes, it is thought that they may play an important role in central nervous system diseases because they can pass through the blood-brain barrier (BBB). Hence, this study aimed to develop an exosome-based nanocarrier system by encapsulating dopamine into exosomes isolated from Wharton's jelly mesenchymal stem cells (WJ-MSCs). Exosomes that passed the characterization process were incubated with dopamine. The dopamine-loaded exosomes were recharacterized at the end of incubation. Dopamine-loaded exosomes were investigated in drug release and cytotoxicity assays. The results showed that dopamine could be successfully encapsulated within the exosomes and that the dopamine-loaded exosomes did not affect fibroblast viability.

Here, we aimed to obtain a formulation by dopamine loading of the isolated exosomes of stem cells from Wharton's jelly mesenchymal stem cells. Exosome isolation and characterization, drug loading into the resulting exosomes, and the cytotoxic activity of the developed formulation are described in this protocol.

Formulación y caracterización de un sistema portador de dopamina basado en exosomas

Exosomes between 40 and 200 nm in size constitute the smallest subgroup of extracellular vesicles. These bioactive vesicles secreted by cells play an ...