This work was funded by a New Faculty Award II from the California Institute of Regenerative Medicine (CIRM; RN2-00921-1), NIH-funded National Research Award (F32-HL104924), and CIRM Training Grant (TG21163). Materials were provided by: Glycosan Biosystems Inc / BioTime and Dr. Stephen Badylak (University of Pittsburgh)

1. Creación de placas recubiertas con PNIPAAm <ol><li> Disolver el 2,6 g de PNIPAAm en 2 ml de una solución de hexano 60% de tolueno / 40%. </li><li> Se calienta la mezcla a 60 ° C durante 10 min con agitación, hasta que se disuelva el PNIPAAm. </li><li> Cortar el papel de filtro en un círculo de diámetro 60 mm y coloque el papel en el embudo Buchner. </li><li> Se filtra la solución a través de un embudo Buchner en el vaso de vidrio previamente pesado (no utilice plásticos, como el hexano se derretirá plásticos). </li><li> Colocar el vaso y su contenido en un vacío de campana (24 psi) O / N (16 horas). Nota: Hasta que el residuo se hace reaccionar con isopropílico se oxidará así que asegúrese de que no entre en contacto con el oxígeno. </li><li> Pesar el vaso de precipitados para establecer el peso de la PNIPAAm. </li><li> Añadir alcohol isopropílico a la PNIPAAm, la creación de un 50/50 w / w solución. </li><li> Coloque 2 ml de la solución en la superficie de la placa de cultivo de tejidos, y el abrigo durante 5 minutos bajo luz UV. </li><li> Lavar la placa con 2 ml de PBS caliente dos vecesantes de usar para el cultivo celular. </li></ol> 2. Creación de láminas de células Nota: láminas de células de células primarias para el órgano diana pueden ser creados usando un número de diferentes métodos, o mediante el recubrimiento de superficies de cultivo de tejidos con el polímero termosensible tal como se describe aquí. Placas termo-sensible Pre-recubiertos también son ofrecidos por varios proveedores. Nota: Este protocolo es para la cultura utilizando una placa de 35 mm. Brevemente, las células se incubaron primero a 37 ° C durante un mínimo de 24 horas a confluencia de establecer conexiones laterales entre las células adyacentes. Para separar las hojas de células, las placas se someten a temperaturas inferiores a 32 ° C. La lámina de células se transfiere a continuación a la fuerte matriz fibrosa de base que contiene un hidrogel permisiva neovascular con las células endoteliales vasculares. <ol><li> Aislar la población celular. Nota: Este método depende de los procedimientos de derivación individuales y el tipo de células. Rata mu lisa aórticacélulas SCLE (RASMC) se utilizan en este ejemplo. Estos son células musculares lisas primarias aisladas de la aorta abdominal de una rata. </li><li> Lavar las células con 2 ml de PBS caliente. </li><li> Añadir 3 ml de tripsina (u otra solución de escisión / disociar) a las células durante 5 min. </li><li> Inhibir la tripsina mediante la adición de 3 ml de los medios de cultivo, o una solución de tampón fosfato (PBS) que contenía 10% suero bovino fetal (FBS). </li><li> Recoger las células en un tubo cónico y contar una alícuota. </li><li> Girar las células a 1.000 rpm (228 xg) durante 5 min. </li><li> Aspirar el sobrenadante y resuspender las células en su medio de crecimiento (medio de cultivo SmGM2 más kit de bala se utiliza para RASMC). </li><li> Coloque el soporte que contiene las células en un termo-sensible placa de 35 mm - PNIPAAm placa recubierta con una concentración que permitirá alcanzar el 100% de confluencia. Nota: Para RASMCs ese número se determinó que era de 100.000 células / cm 2. Sin embargo, debido a la pérdida de células durante el paso, 120% de que va<html> se utiliza Lue. </li><li> Coloque en una incubadora a 37 ° CO / N. Nota: Es importante mantener las células a 37 ° C para mantener la adhesión de células a la placa. </li></ol> 3 Preparación de Matrix Foundational Nota: Varias matrices fibrosas 3D se pueden utilizar para la capa matriz fibrosa fuerte entre las láminas de células delicadas. Algunos ejemplos incluyen: espuma de gel, bioglass, materiales naturales acellularized 26 o nanospun materiales 27,28 La matriz de la vejiga urinaria porcino (UBM) utilizado en estos estudios fue proporcionado generosamente de nuestro colaborador, el Dr. Badylak 29. <ol><li> Antes de usar, determinar las características de la matriz, incluyendo la falta de contenido celular si se utiliza matriz descelulariza, 27,28 viabilidad de células específicas, y el espacio vacío. 22 </li><li> Cortar la matriz de pre-esterilizados en un tamaño y forma deseados. Nota: Aquí, una perforadora se utiliza para cortar un círculo de diámetro 4 mm. </li></ol>ve_title &quot;&gt; 4. células endoteliales Siembra en un neovascular permisivo hidrogel Nota: Las células endoteliales se pueden obtener de una variedad de fuentes, incluyendo la diferenciación de las células madre o progenitoras. En este caso, se utilizan las HUVEC. <ol><li> Utilice cualquier hidrogel permisiva (fibrina, geles de colágeno), siempre y cuando el tiempo de reticulación es suficientemente corto como para permitir que las células permanecen viables. Nota: En este caso, un gel de ácido hialurónico (HA), basado reticulado se utiliza con un puente disulfuro. </li><li> Preparar el hidrogel HA de acuerdo con el protocolo de empresa. </li><li> Recoger las células endoteliales y se dispersan en una solución de una sola célula utilizando tripsina 1x. Nota: Accutase o tampón de disociación celular también podrían utilizarse para la dispersión de células individuales. </li><li> Desactivar la enzima tripsina mediante el uso de una cantidad igual de inhibidor de tripsina de soja (si es importante que las células no entran en contacto con suero) o 10% de FBS en PBS, recogiendo la solución / células en un tubo cónico de 15 ml. </li><li> Cporte de las células, y calcular el volumen necesario para las dimensiones del parche (previamente cuantificados). Nota: Para obtener un parche de 4 mm, se utilizan aquí de 2 millones de células endoteliales. </li><li> Extraer 2 millones de células, y colocarlo en un nuevo tubo cónico de 15 ml. </li><li> Haga girar al (228 xg) durante 5 min. </li><li> Aspirar el sobrenadante, dejando las células como sedimento en un tubo cónico. </li><li> Mezclar los materiales líquidos de HA y gelatina en una ración de 1: 1. A continuación, añadir 80% del volumen total en el tubo cónico que contiene el sedimento. </li><li> Resuspender las células endoteliales en la 1: / mezcla de gelatina 1 HA </li><li> Colocar las células en suspensión en la mezcla de HA / gelatina en la base de matriz fibrosa de la Etapa 2. </li><li> Añadir un quinto (20 por ciento) del volumen total deseado de la reticulante </li><li> Incubar durante 1 hora a 37 ° C. </li></ol> 5. Aislamiento de láminas de células <ol><li> Retire las placas tratadas con PNIPAAm 35 mm que contienen las células de la incubadora y el lugar en una campana de cultivo celular aRT. </li><li> Aspirar rápidamente el medio de las células, y añadir 2 ml de 6% de gelatina normal que se ha calentado a 37 ° C. </li><li> Mientras que la gelatina está todavía caliente, coloque la retícula de metal en la gelatina, sumergiéndolo debajo de la superficie de la gelatina normal (Película 1). </li><li> Toda la placa sobre hielo durante 5 a 7 minutos, lo que permite que la gelatina se endurezca. </li><li> Después de 7 min, utilizar una espátula para separar cuidadosamente los bordes de gelatina desde el lado de la placa, y luego usar fórceps para levantar la retícula de metal de la placa Nota: La gelatina 6%, y la lámina de células debe levantar con la red. </li><li> Mueva la lámina de células a la placa y se coloca en la parte superior de la combinación de matriz de hidrogel de base fibroso, estableciendo cuidadosamente la red en la parte superior de la construcción. Nota: El lado apical de la lámina de células todavía estará en la posición superior. </li><li> Añadir 2 ml de medio caliente (37 ° C). </li><li> Incubar O / N permitiendo que la lámina de células para adherirse a la superficie del hidrogel. </li><li> Retire tretícula de metal después de que la solución se calienta (aproximadamente 1 hora), o al día siguiente. </li></ol>

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We have nothing to disclose.

Los pasos críticos en el protocolo incluyen: el revestimiento de las superficies de la placa con el polímero termosensible y la manipulación de las láminas de células después de enfriar las placas. Debido a que diferentes células exhiben diferentes propiedades físicas, como la adhesividad, el tiempo de elevación debe ser optimizada para cada tipo celular diferente. El segundo, y más desafiante significativamente componente de este protocolo, se centra en la manipulación de la capa celular, un aspecto crítico...

Injection of cells and/or single materials alone has shown variable success in other organ systems and limited success in cardiac regeneration.5,7-12 Currently, stem cell-derived cells are delivered to damaged tissue using a variety of delivery methods including: direct cell injection into tissue and perfusion into the blood supply.13-17 Others have implanted cells alone, materials alone and/or in combination with material carriers to help regenerate damaged organs.18-21 This design combines multiple strategies that provide material strength, patterning in multiple materials and multiple cell types. 
Specifically, the base acellularized fibrous matrix provides the foundational physical strength to the construct, making it suitable for suturing in into the patient, if necessary. The void spaces in the base matrix are filled with endothelial cells in a neovascular permissive hydrogel22 for rapidly establishing vascularization of the implanted construct. This composite is then integrated with pre-patterned cell sheets that allow enhanced cell-to-cell communication, more closely mimic the native tissue.1,23-25 The overall production process for the layered cellular patch is outlined by the flowchart in Figure 1.

<table border="0" cellpadding="0" cellspacing="0" width="695">
	<tbody>
		<tr height="22">
			<td height="22" style="height:22px;width:207px;">Table of Reagents:</td>
			<td style="width:128px;"></td>
			<td style="width:140px;"></td>
			<td style="width:221px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:207px;">Reagent</td>
			<td style="width:128px;">Company</td>
			<td style="width:140px;">Catalogue number</td>
			<td style="width:221px;">Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Calcein-AM</td>
			<td style="width:128px;">Invitrogen</td>
			<td style="width:140px;">C3099</td>
			<td style="width:221px;">Cell tracker / live dye</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Lysotracker Red</td>
			<td style="width:128px;">Invitrogen</td>
			<td style="width:140px;">L7528</td>
			<td style="width:221px;">Cell tracker</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Neutral Red</td>
			<td style="width:128px;">Sigma</td>
			<td style="width:140px;">N7005</td>
			<td style="width:221px;">Visible Cell dye</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:207px;">pNIPAAM</td>
			<td style="width:128px;">Sigma Aldrich</td>
			<td style="width:140px;">412780250</td>
			<td style="width:221px;">Poly(N-isopropylacrylamide)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Toluene</td>
			<td style="width:128px;">Sigma Aldrich</td>
			<td style="width:140px;">244511-1L</td>
			<td style="width:221px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">Hexane</td>
			<td style="width:128px;">Sigma Aldrich</td>
			<td style="width:140px;">296090-1L</td>
			<td style="width:221px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:207px;">RAOSMC</td>
			<td style="width:128px;">Lonza</td>
			<td style="width:140px;">R-ASM-580</td>
			<td style="width:221px;">Rat Aortic Smooth Muscle Cells</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:207px;">SmGM2</td>
			<td style="width:128px;">Lonza</td>
			<td style="width:140px;">CC-4149</td>
			<td style="width:221px;">Smooth Muscle Media</td>
		</tr>
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tissue engineering: construction of a multicellular 3d scaffold for the delivery of layered cell sheets

Muchos tejidos, tales como los corazones humanos adultos, no son capaces de regenerarse adecuadamente después de un daño. 2,3 Estrategias en la ingeniería de tejidos proponen innovaciones para ayudar al cuerpo en la recuperación y reparación. Por ejemplo, los enfoques de TE pueden ser capaces de atenuar la remodelación cardiaca después de infarto de miocardio (MI) y, posiblemente, aumentar la función total del corazón a un nivel casi normal pre-MI. 4 Como con cualquier tejido funcional, regeneración exitosa del tejido cardíaco implica la correcta entrega de los múltiples tipos de células con señales ambientales que favorecen la integración y la supervivencia del injerto de células / tejido implantado. Tejidos reconstituidos deben abordar varios parámetros, entre ellos: señales solubles, interacciones célula a célula, y materiales de matriz evaluados como vehículos de administración, sus efectos sobre la supervivencia celular, la resistencia del material, y la facilitación de la organización de la célula a los tejidos. Los estudios que emplean la inyección directa de células del injerto sólo ignorar estos elementos esenciales. 2,5,6Un diseño tejido combinando estos ingredientes todavía no se ha desarrollado. A continuación, presentamos un ejemplo de diseños integrados que utilizan capas de láminas de células estampadas con dos tipos distintos de materiales de origen biológico que contenga el tipo de células de órganos diana y las células endoteliales para la mejora de la formación de nuevos vasos en el &quot;tejido&quot;. Aunque estos estudios se centran en la generación de tejido de corazón-como, este diseño de tejido se puede aplicar a muchos otros órganos además de corazón con diseño y el material cambios mínimos, y está destinado a ser un producto fuera de la plataforma para las terapias regenerativas. El protocolo contiene cinco pasos detallados. Una temperatura de poli sensible (N -isopropylacrylamide) (PNIPAAm) se utiliza para platos de cultivo de tejidos abrigo. Luego, las células específicas de tejidos se cultivan en la superficie de las placas recubiertas / superficies micropatrón para formar láminas de células con fuertes adherencias laterales. En tercer lugar, se crea una matriz de base para el tejido mediante la combinación de matriz porosa con admisible que neovascularhe hidrogeles y células endoteliales. Finalmente, las láminas de células se levantan de los platos recubiertos PNIPAAm y se transfieren al elemento de base, por lo que la construcción completa.

El diagrama de flujo (Figura 1) muestra el método general de hacer que el parche de varias capas. Láminas de células se separan de la placa tratada PNIPAAm dejando caer la temperatura por debajo de 32 ° C. A continuación, la lámina de células se coloca en la parte superior del hidrogel reticulado que contiene las células endoteliales sembradas en la matriz fibrosa subyacente (Figura 1). Las placas termo-sensible pretratados también se pueden utilizar para crear las láminas de ...

Watch this Scientific Journal Video about Tissue Engineering: Construction of a Multicellular 3D Scaffold for the Delivery of Layered Cell Sheets at JoVE.com

Tissue Engineering: Construction of a Multicellular 3D Scaffold for the Delivery of Layered Cell Sheets

For creation of highly organized structures of complex tissue, one must assemble multiple material and cell types into an integrated composite. This combinatorial design incorporates organ-specific layered cell sheets with two distinct biologically-derived materials containing a strong fibrous matrix base, and endothelial cells for enhancing new vessels formation.

Ingeniería de tejidos: Construcción de un multicelular 3D Andamios para la entrega de láminas de células en capas

Many tissues, such as the adult human hearts, are unable to adequately regenerate after damage.2,3 Strategies in tissue engineering propose innovations to ...

tissue-engineering-construction-multicellular-3d-scaffold-for

Research

JoVE Journal

Bioengineering

14.4K vistas.  University of California, Merced. For creation of highly organized structures of complex tissue, one must assemble multiple material and cell types into an integrated composite. This combinatorial design incorporates organ-specific layered cell sheets with two distinct biologically-derived materials containing a strong fibrous matrix base, and endothelial cells for enhancing new vessels formation.

Video: Tissue Engineering: Construction of a Multicellular 3D Scaffold for the Delivery of Layered Cell Sheets

Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering

We designed a loading device that is capable of applying uniaxial or biaxial mechanical strain to a tissue engineered biocomposites fabricated for transplantation. While the device primarily functions as a bioreactor that mimics the native mechanical strains, it is also outfitted with a load cell for providing force feedback or mechanical testing of the constructs. The device subjects engineered cartilage constructs to biaxial mechanical loading with great precision of loading dose (amplitude and frequency) and is compact enough to fit inside a standard tissue culture incubator. It loads samples directly in a tissue culture plate, and multiple plate sizes are compatible with the system. The device has been designed using components manufactured for precision-guided laser applications. Bi-axial loading is accomplished by two orthogonal stages. The stages have a 50 mm travel range and are driven independently by stepper motor actuators, controlled by a closed-loop stepper motor driver that features micro-stepping capabilities, enabling step sizes of less than 50 nm. A polysulfone loading platen is coupled to the bi-axial moving platform. Movements of the stages are controlled by Thor-labs Advanced Positioning Technology (APT) software. The stepper motor driver is used with the software to adjust load parameters of frequency and amplitude of both shear and compression independently and simultaneously. Positional feedback is provided by linear optical encoders that have a bidirectional repeatability of 0.1 &mu;m and a resolution of 20 nm, translating to a positional accuracy of less than 3 &mu;m over the full 50 mm of travel. These encoders provide the necessary position feedback to the drive electronics to ensure true nanopositioning capabilities. In order to provide the force feedback to detect contact and evaluate loading responses, a precision miniature load cell is positioned between the loading platen and the moving platform. The load cell has high accuracies of 0.15% to 0.25% full scale.

We designed a novel mechanical loading bioreactor that can apply uniaxial or biaxial mechanical strain to a cartilage biocomposite prior to transplantation into an articular cartilage defect.

Diseño de un Carga mecánica Biaxial biorreactor para Ingeniería de Tejidos

We  designed a loading device that is capable of applying uniaxial or biaxial  mechanical strain to a tissue engineered biocomposites fabricated for  ...

Investigación

Bioingeniería

Tissue Engineering of a Human 3D in vitro Tumor Test System

Cancer is one of the leading causes of death worldwide. Current therapeutic strategies are predominantly developed in 2D culture systems, which inadequately reflect physiological conditions in vivo. Biological 3D matrices provide cells an environment in which cells can self-organize, allowing the study of tissue organization and cell differentiation. Such scaffolds can be seeded with a mixture of different cell types to study direct 3D cell-cell-interactions. To mimic the 3D complexity of cancer tumors, our group has developed a 3D in vitro tumor test system.	
	Our 3D tissue test system models the in vivo situation of malignant peripheral nerve sheath tumors (MPNSTs), which we established with our decellularized porcine jejunal segment derived biological vascularized scaffold (BioVaSc). In our model, we reseeded a modified BioVaSc matrix with primary fibroblasts, microvascular endothelial cells (mvECs) and the S462 tumor cell line. For static culture, the vascular structure of the BioVaSc is removed and the remaining scaffold is cut open on one side (Small Intestinal Submucosa SIS-Muc). The resulting matrix is then fixed between two metal rings (cell crowns).	
	Another option is to culture the cell-seeded SIS-Muc in a flow bioreactor system that exposes the cells to shear stress. Here, the bioreactor is connected to a peristaltic pump in a self-constructed incubator. A computer regulates the arterial oxygen and nutrient supply via parameters such as blood pressure, temperature, and flow rate. This setup allows for a dynamic culture with either pressure-regulated pulsatile or constant flow.	
	In this study, we could successfully establish both a static and dynamic 3D culture system for MPNSTs. The ability to model cancer tumors in a more natural 3D environment will enable the discovery, testing, and validation of future pharmaceuticals in a human-like model.

Tissue Engineering of a Human 3D in vitro Tumor Test System

Methods to create human 3D tumor tissues as test systems are described. These technologies are based on a decellularized Biological Vascularized Scaffold (BioVaSc), primary human cells and a tumor cell line, which can be cultured under static as well as under dynamic conditions in a flow bioreactor.

Ingeniería de tejidos de un humano 3D<em&gt; In vitro</em&gt; Sistema de Prueba de Tumores

Cancer is one of the leading causes of death worldwide.  Current therapeutic strategies are predominantly developed in 2D culture  systems, which ...

Self-reporting Scaffolds for 3-Dimensional Cell Culture

Culturing cells in 3D on appropriate scaffolds is thought to better mimic the in vivo microenvironment and increase cell-cell interactions. The resulting 3D cellular construct can often be more relevant to studying the molecular events and cell-cell interactions than similar experiments studied in 2D. To create effective 3D cultures with high cell viability throughout the scaffold the culture conditions such as oxygen and pH need to be carefully controlled as gradients in analyte concentration can exist throughout the 3D construct. Here we describe the methods of preparing biocompatible pH responsive sol-gel nanosensors and their incorporation into poly(lactic-co-glycolic acid) (PLGA) electrospun scaffolds along with their subsequent preparation for the culture of mammalian cells. The pH responsive scaffolds can be used as tools to determine microenvironmental pH within a 3D cellular construct. Furthermore, we detail the delivery of pH responsive nanosensors to the intracellular environment of mammalian cells whose growth was supported by electrospun PLGA scaffolds. The cytoplasmic location of the pH responsive nanosensors can be utilized to monitor intracellular pH (pHi) during ongoing experimentation.

Biocompatible pH responsive sol-gel nanosensors can be incorporated into poly(lactic-co-glycolic acid) (PLGA) electrospun scaffolds. The produced self-reporting scaffolds can be used for in&#160;situ monitoring of microenvironmental conditions whilst culturing cells upon the scaffold. This is beneficial as the 3D cellular construct can be monitored in real-time without disturbing the experiment.

Los andamios de autoinforme para el 3-Dimensional Cultivo Celular

Culturing cells in 3D on appropriate scaffolds is thought to better mimic the in vivo microenvironment and increase cell-cell interactions. The resulting ...

Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled.
The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The &#8220;static bioreactor&#8221; provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues.

In this work, we present a technique for the rapid fabrication of living vascular tissues by direct culturing of collagen, smooth muscle cells and endothelial cells. In addition, a new protocol for the mechanical characterization of engineered vascular tissues is described.

Ingeniería 3D Cellularized colágeno Geles para Vascular Regeneración Tisular

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. ...

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to intrinsic parameters within the process allow a high degree of control over scaffold characteristics including fiber diameter, alignment and porosity. By developing scaffolds with similar dimensions and topographies to organ- or tissue-specific extracellular matrices (ECM), micro-environments representative to those that cells are exposed to in situ can be created. 
The airway bronchiole wall, comprised of three main micro-environments, was selected as a model tissue. Using decellularized airway ECM as a guide, we electrospun the non-degradable polymer, polyethylene terephthalate (PET), by three different protocols to produce three individual electrospun scaffolds optimized for epithelial, fibroblast or smooth muscle cell-culture. Using a commercially available bioreactor system, we stably co-cultured the three cell-types to provide an in vitro model of the airway wall over an extended time period.
This model highlights the potential for such methods being employed in in vitro diagnostic studies investigating important inter-cellular cross-talk mechanisms or assessing novel pharmaceutical targets, by providing a relevant platform to allow the culture of fully differentiated adult cells within 3D, tissue-specific environments.

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Advancements in biomaterial technologies enable the development of three-dimensional multi-cell-type constructs. We have developed electrospinning protocols to produce three individual scaffolds to culture the main structural cells of the airway to provide a 3D in vitro model of the airway bronchiole wall.

Adaptación del Proceso Electrohilado para proporcionar tres ambientes únicos para un Tri-capa<em&gt; In Vitro</em&gt; Modelo de la pared de la vía aérea

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to ...

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 ...

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Historically, most cellular processes have been studied in only 2 dimensions. While these studies have been informative about general cell signaling mechanisms, they neglect important cellular cues received from the structural and mechanical properties of the local microenvironment and extracellular matrix (ECM). To understand how cells interact within a physiological ECM, it is important to study them in the context of 3 dimensional assays. Cell migration, cell differentiation, and cell proliferation are only a few processes that have been shown to be impacted by local changes in the mechanical properties of a 3-dimensional ECM. Collagen I, a core fibrillar component of the ECM, is more than a simple structural element of a tissue. Under normal conditions, mechanical cues from the collagen network direct morphogenesis and maintain cellular structures. In diseased microenvironments, such as the tumor microenvironment, the collagen network is often dramatically remodeled, demonstrating altered composition, enhanced deposition and altered fiber organization. In breast cancer, the degree of fiber alignment is important, as an increase in aligned fibers perpendicular to the tumor boundary has been correlated to poorer patient prognosis1. Aligned collagen matrices result in increased dissemination of tumor cells via persistent migration2,3. The following is a simple protocol for embedding cells within a 3-dimensional, fibrillar collagen hydrogel. This protocol is readily adaptable to many platforms, and can reproducibly generate both aligned and random collagen matrices for investigation of cell migration, cell division, and other cellular processes in a tunable, 3-dimensional, physiological microenvironment.

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Collagen is a core component of the ECM, and provides essential cues for several cellular processes ranging from migration to differentiation and proliferation. Provided here is a protocol for embedding cells within 3D collagen hydrogels, and a more advanced technique for generating randomized or aligned collagen matrices using PDMS microchannels.

Preparación de geles de colágeno en 3D y microcanales para el estudio de las interacciones 3D<em&gt; En Vivo</em

Historically, most cellular processes have been studied in only 2 dimensions.  While these studies have been informative about general cell signaling ...

Fabrication of Inverted Colloidal Crystal Poly(ethylene glycol) Scaffold: A Three-dimensional Cell Culture Platform for Liver Tissue Engineering

The ability to maintain hepatocyte function in vitro, for the purpose of testing xenobiotics&#39; cytotoxicity, studying virus infection and developing drugs targeted at the liver, requires a platform in which cells receive proper biochemical and mechanical cues. Recent liver tissue engineering systems have employed three-dimensional (3D) scaffolds composed of synthetic or natural hydrogels, given their high water retention and their ability to provide the mechanical stimuli needed by the cells. There has been growing interest in the inverted colloidal crystal (ICC) scaffold, a recent development, which allows high spatial organization, homotypic and heterotypic cell interaction, as well as cell-extracellular matrix (ECM) interaction. Herein, we describe a protocol to fabricate the ICC scaffold using poly (ethylene glycol) diacrylate (PEGDA) and the particle leaching method. Briefly, a lattice is made from microsphere particles, after which a pre-polymer solution is added, properly polymerized, and the particles are then removed, or leached, using an organic solvent (e.g., tetrahydrofuran). The dissolution of the lattice results in a highly porous scaffold with controlled pore sizes and interconnectivities that allow media to reach cells more easily. This unique structure allows high surface area for the cells to adhere to as well as easy communication between pores, and the ability to coat the PEGDA ICC scaffold with proteins also shows a marked effect on cell performance. We analyze the morphology of the scaffold as well as the hepatocarcinoma cell (Huh-7.5) behavior in terms of viability and function to explore the effect of ICC structure and ECM coatings. Overall, this paper provides a detailed protocol of an emerging scaffold that has wide applications in tissue engineering, especially liver tissue engineering.

Fabrication of Inverted Colloidal Crystal Polyethylene glycol Scaffold: A Three-dimensional Cell Culture Platform for Liver Tissue Engineering

This manuscript presents a detailed protocol for the fabrication of an emerging three-dimensional hepatocyte culture platform, the inverted colloidal crystal scaffold, and the concomitant techniques to assess hepatocyte behavior. The size-controllable pores, interconnectivity and ability to conjugate extracellular matrix proteins to the poly(ethylene glycol) (PEG) scaffold enhance Huh-7.5 cell performance.

La fabricación de cristal invertida coloidal poli (etilenglicol) Andamios: Una célula Plataforma de cultivo tridimensional para ingeniería de tejidos de hígado

The ability to maintain hepatocyte function in vitro, for the purpose of testing xenobiotics&#39; cytotoxicity, studying virus infection and developing ...

Fabrication of Extracellular Matrix-derived Foams and Microcarriers as Tissue-specific Cell Culture and Delivery Platforms

Cell function is mediated by interactions with the extracellular matrix (ECM), which has complex tissue-specific composition and architecture. The focus of this article is on the methods for fabricating ECM-derived porous foams and microcarriers for use as biologically-relevant substrates in advanced 3D in vitro cell culture models or as pro-regenerative scaffolds and cell delivery systems for tissue engineering and regenerative medicine. Using decellularized tissues or purified insoluble collagen as a starting material, the techniques can be applied to synthesize a broad array of tissue-specific bioscaffolds with customizable geometries. The approach involves mechanical processing and mild enzymatic digestion to yield an ECM suspension that is used to fabricate the three-dimensional foams or microcarriers through controlled freezing and lyophilization procedures. These pure ECM-derived scaffolds are highly porous, yet stable without the need for chemical crosslinking agents or other additives that may negatively impact cell function. The scaffold properties can be tuned to some extent by varying factors such as the ECM suspension concentration, mechanical processing methods, or synthesis conditions. In general, the scaffolds are robust and easy to handle, and can be processed as tissues for most standard biological assays, providing a versatile and user-friendly 3D cell culture platform that mimics the native ECM composition. Overall, these straightforward methods for fabricating customized ECM-derived foams and microcarriers may be of interest to both biologists and biomedical engineers as tissue-specific cell-instructive platforms for in vitro and in vivo applications.

The tissue-specific extracellular matrix (ECM) is a key mediator of cell function. This article describes methods for synthesizing pure ECM-derived foams and microcarriers that are stable in culture without the need for chemical crosslinking for applications in advanced 3D in vitro cell culture models or as pro-regenerative bioscaffolds.

La fabricación de espumas y microportadores derivados de la matriz extracelular como específica de tejido de cultivo celular y las plataformas de entrega

Cell function is mediated by interactions with the extracellular matrix (ECM), which has complex tissue-specific composition and architecture. The focus ...

Bioprinting of Cartilage and Skin Tissue Analogs Utilizing a Novel Passive Mixing Unit Technique for Bioink Precellularization

Bioprinting is a powerful technique for the rapid and reproducible fabrication of constructs for tissue engineering applications. In this study, both cartilage and skin analogs were fabricated after bioink pre-cellularization utilizing a novel passive mixing unit technique. This technique was developed with the aim to simplify the steps involved in the mixing of a cell suspension into a highly viscous bioink. The resolution of filaments deposited through bioprinting necessitates the assurance of uniformity in cell distribution prior to printing to avoid the deposition of regions without cells or retention of large cell clumps that can clog the needle. We demonstrate the ability to rapidly blend a cell suspension with a bioink prior to bioprinting of both cartilage and skin analogs. Both tissue analogs could be cultured for up to 4 weeks. Histological analysis demonstrated both cell viability and deposition of tissue specific extracellular matrix (ECM) markers such as glycosaminoglycans (GAGs) and collagen I respectively.

Cartilage and skin analogs were bioprinted using a nanocellulose-alginate based bioink. The bioinks were cellularized prior to printing via a single step passive mixing unit. The constructs were demonstrated to be uniformly cellularized, have high viability, and exhibit favorable markers of differentiation.

Bioprinting de cartílago y piel análogos de tejido utilizando un pasivo novela mezcla de unidad técnica de Bioink Precellularization

Bioprinting is a powerful technique for the rapid and reproducible fabrication of constructs for tissue engineering applications. In this study, both ...

Ingeniería de tejidos: Construcción de un multicelular 3D Andamios para la entrega de láminas de células en capas

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