Nos gustaría dar las gracias a las granjas de Smithfield de la donación del tejido pulmonar porcino intacta. También nos gustaría agradecer al Dr. Hu Yang, el Dr. Christina Tang y el Departamento de Cirugía Plástica de VCU para permitirnos usar sus equipos. muestras de hidrogel y tejidos se prepararon para la SEM en el Departamento de Anatomía y de las instalaciones Neurobiología Microscopía VCU apoyado, en parte, por fondos del NIH NINDS Core Center de Grant 5 P30 NS047463 y, en parte, por la forma de financiación de los NIH-NCI Cancer Center Proyectos financiados P30 CA016059. SEM de imágenes de muestras en la Instalación Core Caracterización VCU Nanotecnología (NCC). Este trabajo fue financiado por la National Science Foundation, CMMI 1.351.162.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> Solución </td><td> filtro estéril </td><td> Direcciones </td></tr><tr><td> DiH 2 O </td><td> Sí </td><td> DiH 2 O; estéril filtrada </td></tr><tr><td> Solución Triton X-100 0,1% </td><td> Sí </td><td> Bajo campana de humos Añadir 100 ml de Triton X-100 a 100 ml Solución DiH 2 O y agitar hasta que se disuelva; filtro estéril. </td></tr><tr><td> 2% desoxicolato Solution </td><td> Sí </td><td> Bajo campana de humos agregar 2 g de solución de desoxicolato de sodio por 100 ml de DiH 2 O y agitar hasta que se disuelva; filtro estéril </td></tr><tr><td> 1 M NaCl </td><td> Sí </td><td> Añadir 58.44 g de NaCl a 1 L de DiH 2 O; agitar hasta que se disuelva; filtro estéril </td></tr><tr><td> solución de DNasa </td><td> Sí </td><td> Añadir 12.000unidades de DNasa a 1 L DiH 2 O; Añadir 0,156 g MgSO4 (Anhidro), y 0,222 g de CaCl 2; agitar hasta que se disuelva; filtro estéril </td></tr><tr><td> PBS </td><td> Sí </td><td> Combinar 27,2 g de Na 2 HPO 4 · 7H 2 O (dibásico heptahidratado), 80 g de NaCl, y 2 g de KCl con 10 L DiH 2 O; agitar hasta que se disuelva; ajustar el pH a 7,4; filtro estéril </td></tr></tbody></table> Tabla 1: Soluciones requeridos para la descelularización de tejidos. Hacer las soluciones anteriores para el proceso de descelularización. Almacenar a 4 ° C. Aproximadamente se necesitará 2,5 L de un pulmón porcino. 1. Formación de hidrogel <ol><li> Porcino de pulmón descelularización (adaptado de referencias 9,10) <ol><li> Obtener, un cuarto bloque de pulmón porcino normal de un matadero, con el corazón y Vasculature intacto. </li><li> Con unas tijeras de tejido o un bisturí para diseccionar el corazón, vasculatura lo más cerca posible al corazón de corte, vasculatura restante se utilizó en pasos posteriores para perfusión. </li><li> diseccionar cuidadosamente el tejido conectivo que rodea la tráquea, los bronquios, y la vasculatura utilizando un escalpelo o tijeras. NOTA: Determinar el mejor de pulmón a utilizar para el resto del procedimiento por la elección de un pulmón y sin grandes heridas o perforaciones a través de la pleura y grandes cantidades de atelectasia o la oclusión vascular que pueden impedir la eficacia del proceso de descelularización. </li><li> Cortar el pulmón subóptima deja la mayor parte del bronquio unidos a la tráquea como sea posible (corazón, tejido conectivo y los lóbulos del pulmón eliminado podrán ser eliminados). Debe haber un pulmón que permanezcan unidas a la tráquea y la vasculatura. NOTA: Conservar secciones para histología si se desea. 9 </li><li> Cierre bronquios desconectados con abrazaderas o sutura a prevenir el exceso de flujo de retorno. </li></ol><ol start="6"><li> Preparar las soluciones descelularización y refrigerar a 4 ° C hasta que se necesite (Tabla 1). </li><li> El uso de una bomba de mano canulado para ajustarse a la arteria pulmonar, la perfusión del tejido pulmonar 3 veces con agua DI a través tanto de la arteria pulmonar y la tráquea. Perfundir vasculatura primera cada vez. Comienza con alrededor de 1 L en la vasculatura y 1,5 L en la tráquea para cada perfusión, pero como se elimina los desechos celulares más líquido puede ser perfundido a través del sistema. </li><li> Perfundir tanto vasculatura y la tráquea con una solución de Triton X-100. </li><li> Sumergir el tejido pulmonar en una solución de Triton X-100 durante 24 horas a 4 ° C. </li><li> Perfuse vasculatura y tráquea 3 veces con agua DI para enjuagar. </li><li> Perfundir tanto vasculatura y la tráquea con una solución de desoxicolato. </li><li> Sumergir las secciones de tejido en desoxicolato durante 24 horas a 4 ° C. </li><li> Perfuse vasculatura y tráquea 3 veces con agua DI para enjuagar. </li><li>Perfundir tanto vasculatura y la tráquea con una solución de NaCl. </li><li> Sumergir el tejido en solución de NaCl se filtró durante 1 hora a 4 ° C. </li><li> Perfuse vasculatura y tráquea 3 veces con agua DI para enjuagar. </li><li> Perfundir tanto vasculatura y la tráquea con una solución de DNasa. </li><li> Sumergir el tejido en solución filtrada DNasa durante 1 hora a 4 ° C. </li><li> Perfundir tanto vasculatura y la tráquea 5 veces con PBS. </li><li> Diseccionar tejido cartilaginoso notable, tráquea y todo túbulos 2 mm o más de diámetro (que se encuentra principalmente en torno a la hilio y porciones mediales de los pulmones) de la realización de las vías respiratorias, dejando sólo las zonas respiratorias (principalmente las zonas periféricas). </li><li> Diseccionar el tejido en secciones de 1 pulgada o más pequeños. Orientación del tejido no importa para este paso. </li><li> Retirar el exceso de tejido líquido y colocar en tubos de 50 ml cónicos. Congelar el tejido a -80 ° C. NOTA: Conservar secciones de histología para asegurar la eliminación de las células y debri celulars, si se desea. Utilizamos H &amp; E, α-galactosidasa, PicoGreen, hidroxiprolina, ninhidrina, Alcian azul, SDS-PAGE y espectrometría de masas para caracterizar. 9 </li></ol></li><li> Procesamiento de pulmón <ol><li> Retire las tapas de los tubos congelados que contienen tejido pulmonar descelularizado. </li><li> Coloque papel de filtro sobre la abertura del tubo y asegurar con banda de goma. NOTA: El tubo y el contenido todavía se deben congelar cualquier otra manera ponga en -80 ° C hasta que se congele. </li><li> Liofilizar el tejido hasta que todo el exceso de líquido se ha ido, utilizando un secador de congelación de acuerdo con las instrucciones del fabricante. Almacenar a -80 ° C hasta el momento de molino. </li><li> Antes de comenzar añadir nitrógeno líquido para molino congelador para enfriar el aislamiento y los componentes internos de las condiciones de trabajo. </li><li> Retire la barra magnética molino de tubo de molino y agregar el tejido para cubrir el fondo. </li><li> Cambie la barra de molino y agregar el tejido sin apretar. La barra de molino todavía debe moverse libremente. </li><li> Cerrar el tubo molino y place en el molino congelador. </li><li> Llenar nitrógeno líquido para línea de llenado máximo. </li><li> Molino Congelador todo el tejido en polvo fino (aproximadamente 5 min, la tasa de impactación de ~ 600 min -1), en un cilindro de policarbonato con un impactador de acero inoxidable, así como tapones de extremo de acero inoxidable utilizando el molino congelador de acuerdo con las instrucciones del fabricante. Almacenar a -80 ° C hasta que esté listo para su uso. </li></ol></li><li> Micro-porosa formación de gel (8 mg / ml) (adaptado de referencias 9,11) <ol><li> Añadir 1% (w / v) del polvo descelularizado y 0,1% (w / v) de pepsina a M HCl 0,01, con agitación constante (debe ser capaz de ver el flujo en el nivel superior de líquido), a temperatura ambiente, durante 48 hr. NOTA: El polvo se carga estáticamente, por lo que añadir el HCl después el polvo produce la oportunidad para lavar el exceso de las paredes del tubo. </li><li> Después de la digestión durante 48 h, colocar la solución y los reactivos en hielo durante 5 min. </li><li> Usando refrigerado 10% (v / v) de NaOH 0,1 M, unad 11.11% (v / v) 10x PBS (para llevar la solución entera a 1x concentración), llevar la solución de proteína digerida a pH fisiológico de 7,4. NOTA: La solución ahora se puede almacenar a 4 ° C durante un máximo de una semana. Realizar una cinética de gelificación utilizando reometría 9 si se desea. </li></ol></li></ol> 2. El entrecruzamiento hidrogeles para mejorar la resistencia mecánica <ol><li> Las soluciones de 1%, 0,1% y 0,01% w / v solución genipina reticulación se prepararon disolviendo la cantidad necesaria de polvo de genipina en 10% de DMSO. </li><li> Vortex la solución cada 15 min durante 1 hora. </li><li> Añadir solución genipina para cubrir hidrogeles ECM (100 l por cada pocillo de una placa de 96 pocillos) que han sido previamente montados en parte 1.3.4. </li><li> Dejar a cada hidrogel ECM para reticular durante 24 horas a 37 ° C. </li><li> Enjuague el hidrogel ECM 3 veces con PBS hasta que la solución de lavado ya no es de color azul. Los hidrogeles reticulados serán entonces listo para su posterior caracterización y ceestudios de cultivo ll. </li></ol> 3. cultivo celular con microporosa Gel <ol><li> Recubrimiento de dos dimensiones <ol><li> Usando la solución de 1.3.3, añadir 20 l de solución de pregel a cada pocillo de una placa de cultivo tisular de 96 pocillos no tratados. </li><li> refrigere durante la noche a 4 ° C para permitir la adsorción de proteínas a la placa. </li><li> Aspirar solución pregel y enjuague con PBS. </li><li> Células pasantes 9. </li><li> Añadir 10.000 células / cm 2 a los pocillos. </li><li> Aumentar los medios de comunicación a 100 l por pocillo y se incuba a 37 ° C. </li></ol></li><li> Tres de cultivo celular dimensional 9 <ol><li> Utilizando la solución de 1.3.3, resuspender las células sedimentadas a una concentración de 1.000.000 células / ml de solución pregel. </li><li> dispensar rápidamente 16 l de suspensión de células pregel en cada pocillo de una placa de 96 pocillos, para formar un hidrogel de espesor ~ 500 micras para el cultivo celular en 3D. </li><li> Incubar a 37 ° C durante 30min para el gel a la forma. </li><li> Añadir 100 l de medios de comunicación a la parte superior de hidrogeles formados y se incuba a 37 ° C. </li></ol></li><li> Tres de cultivo celular dimensional en geles de rigidez variable <ol><li> Utilizando la solución de 1.3.3, pipeta 100 l de solución de pregel en cada pocillo de una placa de 96 pocillos. </li><li> Incubar a 37 ° C durante 30 minutos para gel a la forma. Nota: El entrecruzamiento pasos de la parte 2 se puede utilizar aquí. </li><li> Células pasantes 9. </li><li> Añadir 10.000 células / cm 2 a los pocillos. </li><li> Aumentar los medios de comunicación a 100 l por pocillo y se incuba a 37 ° C. </li></ol></li></ol>

<ol>
	<li>Lee, J., Cuddihy, M., Kotov, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Three-Dimensional Cell Culture Matrices: State of the Art. 14, (2008).</li><li>Haycock, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 3D Cell Culture. , (2011).</li><li>Walker, J. M., Ed, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Epithelial cell culture protocols. , (2012).</li><li>Badylak, S. F., Freytes, D. O., Gilbert, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+matrix+as+a+biological+scaffold+material:+Structure+and+function.">Extracellular matrix as a biological scaffold material: Structure and function.</a> Acta Biomater. 5 (1), 1-13 (2009).</li><li>Koo, H. -. J., Lim, K. -. H., Jung, H. -. J., Park, E. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anti-inflammatory+evaluation+of+gardenia+extract,+geniposide+and+genipin.">Anti-inflammatory evaluation of gardenia extract, geniposide and genipin.</a> J. Ethnopharmacol. 103 (3), 496-500 (2006).</li><li>Jeffords, M. E., Wu, J., Shah, M., Hong, Y., Zhang, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tailoring+Material+Properties+of+Cardiac+Matrix+Hydrogels+to+Induce+Endothelial+Differentiation+of+Human+Mesenchymal+Stem+Cells.">Tailoring Material Properties of Cardiac Matrix Hydrogels to Induce Endothelial Differentiation of Human Mesenchymal Stem Cells.</a> ACS Appl. Mater. Interfaces. 7 (20), 11053-11061 (2015).</li><li>Suckow, M. A., Voytik-Harbin, S. L., Terril, L. A., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+bone+regeneration+using+porcine+small+intestinal+submucosa.">Enhanced bone regeneration using porcine small intestinal submucosa.</a> J. Invest. Surg. 12 (5), 277-287 (1998).</li><li>Brown, B. N., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+matrix+as+an+inductive+scaffold+for+functional+tissue+reconstruction.">Extracellular matrix as an inductive scaffold for functional tissue reconstruction.</a> Transl. Res. J. Lab. Clin. Med. 163 (4), 268-285 (2014).</li><li>Pouliot, R. 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=Development+and+characterization+of+a+naturally+derived+lung+extracellular+matrix+hydrogel.">Development and characterization of a naturally derived lung extracellular matrix hydrogel.</a> J.Biomed.Mater.Res.A. , (2016).</li><li>Price, A. P., England, K. A., Matson, A. M., Blazar, B. R., Panoskaltsis-Mortari, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+decellularized+lung+bioreactor+system+for+bioengineering+the+lung:+the+matrix+reloaded.">Development of a decellularized lung bioreactor system for bioengineering the lung: the matrix reloaded.</a> Tissue Eng. Part A. 16 (8), 2581-2591 (2010).</li><li>Freytes, D. O., Martin, J., Velankar, S. S., Lee, A. S., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+rheological+characterization+of+a+gel+form+of+the+porcine+urinary+bladder+matrix.">Preparation and rheological characterization of a gel form of the porcine urinary bladder matrix.</a> Biomaterials. 29 (11), 1630-1637 (2008).</li><li>Tilghman, R. W., 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=Matrix+rigidity+regulates+cancer+cell+growth+and+cellular+phenotype.">Matrix rigidity regulates cancer cell growth and cellular phenotype.</a> PloS One. 5 (9), e12905 (2010).</li><li>Ratner, B. D., Bryant, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomaterials:+where+we+have+been+and+where+we+are+going.">Biomaterials: where we have been and where we are going.</a> Annu. Rev. Biomed. Eng. 6, 41-75 (2004).</li><li>Fridman, R., Benton, G., Aranoutova, I., Kleinman, H. K., Bonfil, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+initiation+and+growth+of+tumor+cell+lines,+cancer+stem+cells+and+biopsy+material+in+mice+using+basement+membrane+matrix+protein+(Cultrex+or+Matrigel)+co-injection.">Increased initiation and growth of tumor cell lines, cancer stem cells and biopsy material in mice using basement membrane matrix protein (Cultrex or Matrigel) co-injection.</a> Nat Protoc. 7 (6), 1138-1144 (2012).</li><li>Zhang, W. -. J., 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=The+reconstruction+of+lung+alveolus-like+structure+in+collagen-matrigel/microcapsules+scaffolds+in+vitro.">The reconstruction of lung alveolus-like structure in collagen-matrigel/microcapsules scaffolds in vitro.</a> J. Cell. Mol. Med. 15 (9), 1878-1886 (2011).</li><li>Booth, A. J., 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=Acellular+Normal+and+Fibrotic+Human+Lung+Matrices+as+a+Culture+System+for+In+Vitro+Investigation.">Acellular Normal and Fibrotic Human Lung Matrices as a Culture System for In Vitro Investigation.</a> Am. J. Respir. Crit. Care Med. 186 (9), 866-876 (2016).</li><li>Matsuda, 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=Evidence+for+human+lung+stem+cells.">Evidence for human lung stem cells.</a> N. Engl. J. Med. 364 (19), 1795-1806 (2011).</li><li>Zuo, W., 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=p63+Krt5++distal+airway+stem+cells+are+essential+for+lung+regeneration.">p63+Krt5+ distal airway stem cells are essential for lung regeneration.</a> Nature. 517 (7536), 616-620 (2015).</li><li>Keane, T. J., Londono, R., Turner, N. J., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Consequences+of+ineffective+decellularization+of+biologic+scaffolds+on+the+host+response.">Consequences of ineffective decellularization of biologic scaffolds on the host response.</a> Biomaterials. 33 (6), 1771-1781 (2012).</li><li>Neill, J. D., 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=Decellularization+of+human+and+porcine+lung+tissues+for+pulmonary+tissue+engineering.">Decellularization of human and porcine lung tissues for pulmonary tissue engineering.</a> Ann Thorac Surg. 96 (3), 1046-1055 (2013).</li></ol>

Los autores no tienen nada que revelar.

Uno de los aspectos integrales de la biología es la auto-organización de las moléculas en estructuras jerárquicas que realizan una tarea específica. 13 En el laboratorio, el autoensamblaje depende de numerosos factores tales como la concentración de sal, pH, y la duración de digestión. Como se muestra, se forma un hidrogel de auto-organización cuando las proteínas solubilizadas vuelve a la temperatura fisiológica. El hidrogel formado es capaz de promover la unión celular y la proliferación in...

Translating in vitro results to the clinic is one of the most challenging issues facing biomedical researchers. In vitro research on tissue culture plastic is easier, more convenient, and maintains high cell viability.1 This approach is a reasonable starting point, but the results have limited clinical translation. Increasingly, laboratories are incorporating three-dimensional constructs to replace the traditional two-dimensional methods. Reviews are available for many three-dimensional environments, from biological scaffolds to polymeric scaffolds.2,3
Biological frameworks can mimic characteristics of in vivo environments as they contain many of the protein and glycosaminoglycan components of the native matrix and provide familiar binding sites for cells to attach to and recognize. Extracellular matrix (ECM) derived materials have been shown to be capable scaffolds for cell attachment and proliferation.4 One challenge that limits the application of ECM hydrogel platforms stems from their inherently weak mechanical properties following gelation. Native tissue often has mechanical properties that are magnitudes higher than hydrogels. Non-toxic crosslinking agents can increase the mechanical properties of hydrogels to better mimic the native tissue environment. Genipin is a non-toxic, natural crosslinker derived from Gardenia plants with the ability to closely tailor mechanical properties of ECM with changes in genipin concentration5,6. 
Nearly all cells in the body exist in, and organize on, ECM that they either produce or maintain. New focus on the universal importance of ECM in the organization, condition, and function in every organ or system has sparked the production of matrix based platforms for in vitro investigation. Porcine small intestine submucosa is the most extensively studied naturally-derived scaffold, and it has been used to regenerate tendons, ligaments, skeletal muscle4, and even bone7. Matrices from other organs and donor species have also demonstrated good tissue regeneration potential. The use of foreign ECM components causes minimal issues with immunomodulation. After elimination of host cellular matter, the remaining ECM will be similar in amino acid content and organization to all other mammalian species8. There is a growing line of thinking that the best way to examine cell-ECM interactions in vitro is to utilize organ-specific ECM scaffolds. Each organ provides a unique composition of proteins and proteoglycans to create cellular niches. Niches provide structural, functional and even the enzymatic breakdown of the extracellular matrix contributing to biophysical signaling. To attain an in vitro microenvironment most similar to the in vivo microenvironment, use of tissue specific ECM would optimize the cellular niches for research. 
The goal of this protocol is to provide a method for establishing a hydrogel scaffold unique to the lung ECM. This method provides a platform for in vitro research on lung cell-ECM interactions.

<table><tbody><tr><td>Triton X-100&amp;nbsp;</td><td>Fisher Scientific</td><td>BP151-100</td><td>Use in fume hood with eye protection and gloves.</td></tr><tr><td>Sodium Deoxycholate</td><td>Sigma-Aldrich</td><td>D6750-100g</td><td>Use in hood with eye protection and gloves.</td></tr><tr><td>Magnesium Sulfate</td><td>Sigma-Aldrich</td><td>M7506-500g</td><td>None</td></tr><tr><td>Calcium Chloride</td><td>Sigma-Aldrich</td><td>C1016-500g</td><td>None</td></tr><tr><td>DNase</td><td>Sigma-Aldrich</td><td>D5025-150KU</td><td>None</td></tr><tr><td>HCl</td><td>Sigma-Aldrich</td><td>258148-500ML</td><td>Use with eye protection and gloves.</td></tr><tr><td>Pepsin</td><td>Sigma-Aldrich</td><td>P6887-5G</td><td>Use in fume hood with eye protection and gloves.</td></tr><tr><td>Sodium Hydroxide</td><td>Fisher Scientific</td><td>BP359-500</td><td>Use with eye protection and gloves.</td></tr><tr><td>Genipin</td><td>Wako Chemicals</td><td>078-03021</td><td>Use in fume hood with eye protection and gloves.</td></tr><tr><td>PBS 10x</td><td>Quality Biological</td><td>119-069-151</td><td>None</td></tr><tr><td>PBS</td><td>VWR</td><td>45000-448</td><td>None</td></tr><tr><td>Filter Paper</td><td>Whatman</td><td>8519</td><td>N/A</td></tr><tr><td>Hand pump</td><td>Fisher Scientific</td><td>10-239-1</td><td>N/A</td></tr><tr><td>Graduate Beaker</td><td>VitLab</td><td>445941</td><td>N/A</td></tr><tr><td>Cryomill</td><td>SPEX</td><td>6700</td><td>Use cryogloves and eye protection.</td></tr><tr><td>Lyophilizer</td><td>FTS FlexiDry</td><td></td><td>Use gloves.</td></tr><tr><td>Rheometer</td><td>Discovery</td><td>HR-2</td><td>Use gloves and eye protection.</td></tr></tbody></table>

tunable hydrogels from pulmonary extracellular matrix for 3d cell culture

Aquí presentamos un método para establecer múltiples hidrogeles de cultivo de células de componentes para el cultivo in vitro de células de pulmón en. Comenzando con sano en tejido bloque de pulmón de porcino, de rata, o un ratón, el tejido es perfundido y sumergido en detergentes químicos subsiguientes para eliminar los restos celulares. comparación histológica del tejido antes y después del procesamiento confirma la eliminación de más del 95% de la doble tinción de ADN y alfa galactosidasa hebra sugiere se elimina la mayoría de los restos celulares. Después de la descelularización, el tejido es liofilizada y después cryomilled en un polvo. El polvo de la matriz se digiere durante 48 horas en una solución de digestión con pepsina ácida y después se neutralizó para formar la solución pregel. La gelificación de la solución pregel puede ser inducida por la incubación a 37 ° C y puede ser utilizado inmediatamente después de la neutralización o se almacenaron a 4 ° C durante hasta dos semanas. Los recubrimientos se pueden formar usando la solución pregel en una placa no tratada para capego ell. Las células pueden ser suspendidas en el pregel antes de la auto-ensamblaje de lograr una cultura 3D, chapada en la superficie de un gel formado a partir de la cual las células pueden migrar a través del andamio, o chapada en los revestimientos. Las alteraciones en la estrategia presentada puede afectar la temperatura de gelificación, la fuerza o el tamaño de los fragmentos de proteínas. Más allá de la formación del hidrogel, la rigidez de hidrogel se puede incrementar utilizando genipina.

Usando este método, hemos producido hidrogeles de cerdo normal de rata, y los pulmones de ratón (Figura 1). pulmones procesados ​​proporcionan un estimado de 5 mg, 40 mg, y 10 g de polvo de ECM respectivamente. Una visión general del proceso se muestra en la Figura 2. visualizaciones clave durante el proceso incluyen: aspecto blanco de los pulmones después de aclarar desoxicolato; después de la formación pregel, la solución debe ser opaca y la...

Watch this Scientific Journal Video about Tunable Hydrogels from Pulmonary Extracellular Matrix for 3D Cell Culture at JoVE.com

Tunable Hydrogels from Pulmonary Extracellular Matrix for 3D Cell Culture

Este es un método para crear un andamio de cultivo celular de 3 dimensiones de la matriz extracelular pulmonar. pulmonar intacta se procesa en hidrogeles que pueden apoyar el crecimiento de células en tres dimensiones.

Los hidrogeles sintonizable de la matriz extracelular pulmonar por la 3D de Cultivos Celulares

Here we present a method for establishing multiple component cell culture hydrogels for in vitro lung cell culture. Beginning with healthy en bloc lung ...

tunable-hydrogels-from-pulmonary-extracellular-matrix-for-3d-cell

Universidad de Cartagena UDEC

Research

JoVE Journal

Bioengineering

11.6K vistas.  Virginia Commonwealth University.  Este es un método para crear un andamio de cultivo celular de 3 dimensiones de la matriz extracelular pulmonar. pulmonar intacta se procesa en hidrogeles que pueden apoyar el crecimiento de células en tres dimensiones. 

Video: Tunable Hydrogels from Pulmonary Extracellular Matrix for 3D Cell Culture

Fabrication of Micropatterned Hydrogels for Neural Culture Systems using Dynamic Mask Projection Photolithography

Increasingly, patterned cell culture environments are becoming a relevant technique to study cellular characteristics, and many researchers believe in the need for 3D environments to represent in vitro experiments which better mimic in vivo qualities 1-3. Studies in fields such as cancer research 4, neural engineering 5, cardiac physiology 6, and cell-matrix interaction7,8have shown cell behavior differs substantially between traditional monolayer cultures and 3D constructs.
Hydrogels are used as 3D environments because of their variety, versatility and ability to tailor molecular composition through functionalization 9-12. Numerous techniques exist for creation of constructs as cell-supportive matrices, including electrospinning13, elastomer stamps14, inkjet printing15, additive photopatterning16, static photomask projection-lithography17, and dynamic mask microstereolithography18. Unfortunately, these methods involve multiple production steps and/or equipment not readily adaptable to conventional cell and tissue culture methods. The technique employed in this protocol adapts the latter two methods, using a digital micromirror device (DMD) to create dynamic photomasks for crosslinking geometrically specific poly-(ethylene glycol) (PEG) hydrogels, induced through UV initiated free radical polymerization. The resulting "2.5D" structures provide a constrained 3D environment for neural growth. We employ a dual-hydrogel approach, where PEG serves as a cell-restrictive region supplying structure to an otherwise shapeless but cell-permissive self-assembling gel made from either Puramatrix or agarose. The process is a quick simple one step fabrication which is highly reproducible and easily adapted for use with conventional cell culture methods and substrates.
Whole tissue explants, such as embryonic dorsal root ganglia (DRG), can be incorporated into the dual hydrogel constructs for experimental assays such as neurite outgrowth. Additionally, dissociated cells can be encapsulated in the photocrosslinkable or self polymerizing hydrogel, or selectively adhered to the permeable support membrane using cell-restrictive photopatterning. Using the DMD, we created hydrogel constructs up to ~1mm thick, but thin film (&lt;200 &mu;m) PEG structures were limited by oxygen quenching of the free radical polymerization reaction. We subsequently developed a technique utilizing a layer of oil above the polymerization liquid which allowed thin PEG structure polymerization.
In this protocol, we describe the expeditious creation of 3D hydrogel systems for production of microfabricated neural cell and tissue cultures. The dual hydrogel constructs demonstrated herein represent versatile in vitro models that may prove useful for studies in neuroscience involving cell survival, migration, and/or neurite growth and guidance. Moreover, as the protocol can work for many types of hydrogels and cells, the potential applications are both varied and vast.

Simple techniques are described for the rapid production of microfabricated neural culture systems using a digital micromirror device for dynamic mask projection lithography on regular cell culture substrates. These culture systems may be more representative of natural biological architecture, and the techniques described could be adapted for numerous applications.

Fabricación de hidrogeles micropatterned para sistemas de cultivo neuronal usando fotolitografía dinámica de proyección Máscara

Increasingly, patterned cell culture environments are becoming a relevant technique to study cellular characteristics, and many researchers believe in the ...

Investigación

Bioingeniería

Easy Manipulation of Architectures in Protein-based Hydrogels for Cell Culture Applications

Hydrogels are recognized as promising materials for cell culture applications due to their ability to provide highly hydrated cell environments. The field of 3D templates is rising due to the potential resemblance of those materials to the natural extracellular matrix. Protein-based hydrogels are particularly promising because they can easily be functionalized and can achieve defined structures with adjustable physicochemical properties. However, the production of macroporous 3D templates for cell culture applications using natural materials is often limited by their weaker mechanical properties compared to those of synthetic materials. Here, different methods were evaluated to produce macroporous bovine serum albumin (BSA)-based hydrogel systems, with adjustable pore sizes in the range of 10 to 70 &#181;m in radius. Furthermore, a method to generate channels in this protein-based material that are several hundred microns long was established. The different methods to produce pores, as well as the influence of pore size on material properties such as swelling ratio, pH, temperature stability, and enzymatic degradation behavior, were analyzed. Pore sizes were investigated in the native, swollen state of the hydrogels using confocal laser scanning microscopy. The feasibility for cell culture applications was evaluated using a cell-adhesive RGD peptide modification of the protein system and two model cell lines: human breast cancer cells (A549) and adenocarcinomic human alveolar basal epithelial cells (MCF7).

Different methods to manipulate three-dimensional architecture in protein-based hydrogels are evaluated here with respect to material properties. The macroporous networks are functionalized with a cell-adhesive peptide, and their feasibility in cell culture is evaluated using two different model cell lines.

Fácil manipulación de arquitecturas en Hidrogeles basados en proteínas para aplicaciones de la cultura de célula

Hydrogels are recognized as promising materials for cell culture applications due to their ability to provide highly hydrated cell environments. The field ...

Bioquímica

Construction of Modular Hydrogel Sheets for Micropatterned Macro-scaled 3D Cellular Architecture

Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue geometry. The resulting 3D hydrogel-based cellular constructs have been introduced as an alternative to animal experiments for advanced biological studies, pharmacological assays and organ transplant applications. Although hydrogel-based particles and fibers can be easily fabricated, it is difficult to manipulate them for tissue reconstruction. In this video, we describe a fabrication method for micropatterned alginate hydrogel sheets, together with their assembly to form a macro-scale 3D cell culture system with a controlled cellular microenvironment. Using a mist form of the calcium gelling agent, thin hydrogel sheets are easily generated with a thickness in the range of 100 - 200 &#181;m, and with precise micropatterns. Cells can then be cultured with the geometric guidance of the hydrogel sheets in freestanding conditions. Furthermore, the hydrogel sheets can be readily manipulated using a micropipette with an end-cut tip, and can be assembled into multi-layered structures by stacking them using a patterned polydimethylsiloxane (PDMS) frame. These modular hydrogel sheets, which can be fabricated using a facile process, have potential applications of in vitro drug assays and biological studies, including functional studies of micro- and macrostructure and tissue reconstruction.

We describe the fabrication of micropatterned hydrogel sheets using a simple process, which can be assembled and manipulated in a freestanding form. Using these modular hydrogel sheets, a simple macro-scaled 3D cell culture system can be generated with a controlled cellular microenvironment.

Construcción de Hojas modular de hidrogel para la arquitectura celular 3D a escala macro micropatterned

Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue ...

Bioprinting Cellularized Constructs Using a Tissue-specific Hydrogel Bioink

Bioprinting has emerged as a versatile biofabrication approach for creating tissue engineered organ constructs. These constructs have potential use as organ replacements for implantation in patients, and also, when created on a smaller size scale as model "organoids" that can be used in in vitro systems for drug and toxicology screening.
Despite development of a wide variety of bioprinting devices, application of bioprinting technology can be limited by the availability of materials that both expedite bioprinting procedures and support cell viability and function by providing tissue-specific cues. Here we describe a versatile hyaluronic acid (HA) and gelatin-based hydrogel system comprised of a multi-crosslinker, 2-stage crosslinking protocol, which can provide tissue specific biochemical signals and mimic the mechanical properties of in vivo tissues. 
Biochemical factors are provided by incorporating tissue-derived extracellular matrix materials, which include potent growth factors. Tissue mechanical properties are controlled combinations of PEG-based crosslinkers with varying molecular weights, geometries (linear or multi-arm), and functional groups to yield extrudable bioinks and final construct shear stiffness values over a wide range (100 Pa to 20 kPa). Using these parameters, hydrogel bioinks were used to bioprint primary liver spheroids in a liver-specific bioink to create in vitro liver constructs with high cell viability and measurable functional albumin and urea output. This methodology provides a general framework that can be adapted for future customization of hydrogels for biofabrication of a wide range of tissue construct types.

We describe a set of protocols that together provide a tissue-mimicking hydrogel bioink with which functional and viable 3-D tissue constructs can be bioprinted for use in in vitro screening applications.

Bioprinting Cellularized Construye El uso de un Tejidos específicos de hidrogel Bioink

Bioprinting has emerged as a versatile biofabrication approach for creating tissue engineered organ constructs. These constructs have potential use as ...

3D Microtissues for Injectable Regenerative Therapy and High-throughput Drug Screening

To upgrade traditional 2D cell culture to 3D cell culture, we have integrated microfabrication with cryogelation technology to produce macroporous microscale cryogels (microcryogels), which can be loaded with a variety of cell types to form 3D microtissues. Herein, we present the protocol to fabricate versatile 3D microtissues and their applications in regenerative therapy and drug screening. Size and shape-controllable microcryogels can be fabricated on an array chip, which can be harvested off-chip as individual cell-loaded carriers for injectable regenerative therapy or be further assembled on-chip into 3D microtissue arrays for high-throughput drug screening. Due to the high elastic nature of these microscale cryogels, the 3D microtissues exhibit great injectability for minimally invasive cell therapy by protecting cells from mechanical shear force during injection. This ensures enhanced cell survival and therapeutic effect in the mouse limb ischemia model. Meanwhile, assembly of 3D microtissue arrays in a standard 384-multi-well format facilitates the use of common laboratory facilities and equipment, enabling high-throughput drug screening on this versatile 3D cell culture platform.

This protocol describes the fabrication of elastic 3D macroporous microcryogels by integrating microfabrication with cryogelation technology. Upon loading with cells, 3D microtissues are generated, which can be readily injected in vivo to facilitate regenerative therapy or assembled into arrays for in vitro high-throughput drug screening.

Microtissues 3D para la terapia regenerativa inyectable y drogas de alto rendimiento

To upgrade traditional 2D cell culture to 3D cell culture, we have integrated microfabrication with cryogelation technology to produce macroporous ...

Ultrathin Porated Elastic Hydrogels As a Biomimetic Basement Membrane for Dual Cell Culture

The basement membrane is a critical component of cellular bilayers that can vary in stiffness, composition, architecture, and porosity. In vitro studies of endothelial-epithelial bilayers have traditionally relied on permeable support models that enable bilayer culture, but permeable supports are limited in their ability to replicate the diversity of human basement membranes. In contrast, hydrogel models that require chemical synthesis are highly tunable and allow for modifications of both the material stiffness and the biochemical composition via incorporation of biomimetic peptides or proteins. However, traditional hydrogel models are limited in functionality because they lack pores for cell-cell contacts and functional in vitro migration studies. Additionally, due to the thickness of traditional hydrogels, incorporation of pores that span the entire thickness of hydrogels has been challenging. In the present study, we use poly-(ethylene-glycol) (PEG) hydrogels and a novel zinc oxide templating method to address the previous shortcomings of biomimetic hydrogels. As a result, we present an ultrathin, basement membrane-like hydrogel that permits the culture of confluent cellular bilayers on a customizable scaffold with variable pore architectures, mechanical properties, and biochemical composition.

Current bilayer culture models do not allow for functional in vitro studies that mimic in vivo microenvironments. Using polyethylene glycol and a zinc oxide templating method, this protocol describes the development of an ultrathin biomimetic basement membrane with tunable stiffness, porosity, and biochemical composition that closely mimics in vivo extracellular matrices.

Hidrogeles ultrafino Porated elástico como una membrana del sótano biomiméticos para doble cultura de la célula

The basement membrane is a critical component of cellular bilayers that can vary in stiffness, composition, architecture, and porosity. In vitro studies ...

Production of Elastin-like Protein Hydrogels for Encapsulation and Immunostaining of Cells in 3D

Two-dimensional (2D) tissue culture techniques have been essential for our understanding of fundamental cell biology. However, traditional 2D tissue culture systems lack a three-dimensional (3D) matrix, resulting in a significant disconnect between results collected in vitro and in vivo. To address this limitation, researchers have engineered 3D hydrogel tissue culture platforms that can mimic the biochemical and biophysical properties of the in vivo cell microenvironment. This research has motivated the need to develop material platforms that support 3D cell encapsulation and downstream biochemical assays. Recombinant protein engineering offers a unique toolset for 3D hydrogel material design and development by allowing for the specific control of protein sequence and therefore, by extension, the potential mechanical and biochemical properties of the resultant matrix. Here, we present a protocol for the expression of recombinantly-derived elastin-like protein (ELP), which can be used to form hydrogels with independently tunable mechanical properties and cell-adhesive ligand concentration. We further present a methodology for cell encapsulation within ELP hydrogels and subsequent immunofluorescent staining of embedded cells for downstream analysis and quantification.

Recombinant protein-engineered hydrogels are advantageous for 3D cell culture as they allow for complete tunability of the polymer backbone and therefore, the cell microenvironment. Here, we describe the process of recombinant elastin-like protein purification and its application in 3D hydrogel cell encapsulation.

Producción de la proteína elastina como hidrogeles para encapsulación y el Immunostaining de células en 3D

Two-dimensional (2D) tissue culture techniques have been essential for our understanding of fundamental cell biology. However, traditional 2D tissue ...

Controlled Strain of 3D Hydrogels under Live Microscopy Imaging

External forces are an important factor in tissue formation, development, and maintenance. The effects of these forces are often studied using specialized in vitro stretching methods. Various available systems use 2D substrate-based stretchers, while the accessibility of 3D techniques to strain soft hydrogels, is more restricted. Here, we describe a method that allows external stretching of soft hydrogels from their circumference, using an elastic silicone strip as the sample carrier. The stretching system utilized in this protocol is constructed from 3D-printed parts and low-cost electronics, making it simple and easy to replicate in other labs. The experimental process begins with polymerizing thick (&#62;100 &#956;m) soft fibrin hydrogels (Elastic Modulus of ~100 Pa) in a cut-out at the center of a silicone strip. Silicone-gel constructs are then attached to the printed-stretching device and placed on the confocal microscope stage. Under live microscopy the stretching device is activated, and the gels are imaged at various stretch magnitudes. Image processing is then used to quantify the resulting gel deformations, demonstrating relatively homogenous strains and fiber alignment throughout the gel&#8217;s 3D thickness (Z-axis). Advantages of this method include the ability to strain extremely soft hydrogels in 3D while executing in situ microscopy, and the freedom to manipulate the geometry and size of the sample according to the user&#8217;s needs. Additionally, with proper adaptation, this method can be used to stretch other types of hydrogels (e.g., collagen, polyacrylamide or polyethylene glycol) and can allow for analysis of cells and tissue response to external forces under more biomimetic 3D conditions.

The presented method involves uniaxial stretching of 3D soft hydrogels embedded in silicone rubber while allowing live confocal microscopy. Characterization of the external and internal hydrogel strains as well as fiber alignment are demonstrated. The device and protocol developed can assess the response of cells to various strain regimes.

Cepa controlada de hidrogeles 3D bajo imágenes de microscopía en vivo

External forces are an important factor in tissue formation, development, and maintenance. The effects of these forces are often studied using specialized ...

Hydrogel Arrays Enable Increased Throughput for Screening Effects of Matrix Components and Therapeutics in 3D Tumor Models

Cell-matrix interactions mediate complex physiological processes through biochemical, mechanical, and geometrical cues, influencing pathological changes and therapeutic responses. Accounting for matrix effects earlier in the drug development pipeline is expected to increase the likelihood of clinical success of novel therapeutics. Biomaterial-based strategies recapitulating specific tissue microenvironments in 3D cell culture exist but integrating these with the 2D culture methods primarily used for drug screening has been challenging. Thus, the protocol presented here details the development of methods for 3D culture within miniaturized biomaterial matrices in a multi-well plate format to facilitate integration with existing drug screening pipelines and conventional assays for cell viability. Since the matrix features critical for preserving clinically relevant phenotypes in cultured cells are expected to be highly tissue- and disease-specific, combinatorial screening of matrix parameters will be necessary to identify appropriate conditions for specific applications. The methods described here use a miniaturized culture format to assess cancer cell responses to orthogonal variation of matrix mechanics and ligand presentation. Specifically, this study demonstrates the use of this platform to investigate the effects of matrix parameters on the responses of patient-derived glioblastoma (GBM) cells to chemotherapy.

The present protocol describes an experimental platform to assess the effects of mechanical and biochemical cues on chemotherapeutic responses of patient-derived glioblastoma cells in 3D matrix-mimetic cultures using a custom-made UV illumination device facilitating high-throughput photocrosslinking of hydrogels with tunable mechanical features.

Las matrices de hidrogel permiten un mayor rendimiento para los efectos de detección de los componentes de la matriz y la terapéutica en modelos tumorales 3D

Cell-matrix interactions mediate complex physiological processes through biochemical, mechanical, and geometrical cues, influencing pathological changes ...

Hidrogeles bioimpresos fotoajustables para sondear las respuestas celulares al endurecimiento de la MEC

3D Bioprinting Phototunable Hydrogels to Study Fibroblast Activation

Phototunable hydrogels can transform spatially and temporally in response to light exposure. Incorporating these types of biomaterials in cell-culture platforms and dynamically triggering changes, such as increasing microenvironmental stiffness, enables researchers to model changes in the extracellular matrix (ECM) that occur during fibrotic disease progression. Herein, a method is presented for 3D bioprinting a phototunable hydrogel biomaterial capable of two sequential polymerization reactions within a gelatin support bath. The technique of Freeform Reversible Embedding of Suspended Hydrogels (FRESH) bioprinting was adapted by adjusting the pH of the support bath to facilitate a Michael addition reaction. First, the bioink containing poly(ethylene glycol)-alpha methacrylate (PEG&#945;MA) was reacted off-stoichiometry with a cell-degradable crosslinker to form soft hydrogels. These soft hydrogels were later exposed to photoinitator and light to induce the homopolymerization of unreacted groups and stiffen the hydrogel. This protocol covers hydrogel synthesis, 3D bioprinting, photostiffening, and endpoint characterizations to assess fibroblast activation within 3D structures. The method presented here enables researchers to 3D bioprint a variety of materials that undergo pH-catalyzed polymerization reactions and could be implemented to engineer various models of tissue homeostasis, disease, and repair.

Autor destacado: Comprensión de las enfermedades pulmonares crónicas mediante hidrogeles fotoajustables impresos en 3D 

This article describes how to 3D bioprint phototunable hydrogels to study extracellular matrix stiffening and fibroblast activation.

Bioimpresión 3D de hidrogeles fotoajustables para estudiar la activación de fibroblastos

Phototunable hydrogels can transform spatially and temporally in response to light exposure. Incorporating these types of biomaterials in cell-culture ...