This research was supported by the Technology Innovation Program (Contract grant No. 0037915, WPM Biomedical Materials-Implant Materials) and Industrial Strategic Technology Development Program (Contract grant No. 10045329, Development of customized implant with porous structure for bone replacement), funded by the Ministry of Trade, industry &#38; Energy (MI, Korea), and BK21 PLUS SNU Materials Division for Educating Creative Global Leaders (Contract grant No. 21A20131912052).

1. La fabricación de andamios porosos de metal <ol><li> Preparar suspensiones Ti-canfeno mezclando disponible comercialmente polvo de Ti, canfeno, y KD-4 después de pesar las cantidades apropiadas de materiales como se describe en la Tabla 1 para andamios porosos Ti con cuatro porosidades iniciales (40, 50, 60, y 70). Verter las suspensiones en 500 ml de polietileno (PE) y girar las botellas botellas a 55 ° C durante 30 min en un horno de molino de bolas a 30 rpm. </li><li> Verter las suspensiones de las botellas de PE en cilíndrico de aluminio (Al) moldes con un diámetro de 60 mm y una altura de 60 mm. Cerrar cada molde de Al con el correspondiente hoja de cubierta Al y girar los moldes en un horno de molino de bolas a una velocidad de 30 rpm a 55 ° C durante 10 min. <ol><li> Posteriormente, disminuir la temperatura del horno molino de bolas a 44 ° C, y continuamente girar los moldes a una velocidad de 30 rpm a la temperatura constante de 44 ° C durante 12 hr. </li></ol></li><li> Saque el molde de la bola-molino de horno después adicionalmente la rotación de los moldes a temperatura ambiente durante 1 hr para el proceso de enfriamiento. Retire el titanio / canfeno cuerpo verde solidificada del molde Al usar un Al émbolo. </li><li> Coloque el titanio / canfeno cuerpo verde solidificado en una bolsa de goma a mano y sellar completamente la bolsa de caucho mediante la vinculación de la boca de la bolsa con una cadena. Colocar la bolsa de goma en el tanque de agua de una presión (CIP) de la máquina isostático en frío y aplicar una presión isostática de 200 MPa durante 10 min. Retire el cuerpo verde comprimido de la bolsa de goma. </li><li> Transferir el cuerpo verde Ti-canfeno a un crisol de alúmina a mano y colocar el crisol en la máquina liofilizador. Liofilizar el cuerpo verde para sublimar la fase canfeno en el cuerpo verde en - 40 ° C durante 24 hr. </li><li> Posteriormente, cierre el crisol con una hoja de cubierta de aluminio y colocar el crisol cerrado en un horno de vacío (por debajo de 10 -6 Torr) a TA. A continuación, aumentar la temperatura del horno a 1300 ° C a una calefacción rcomió de 5 ° C / min y mantenga la temperatura a 1300 ° C durante 2 horas. </li><li> Después del tratamiento térmico, mantener el sinterizado poroso Ti en el horno 6-7 por hr hasta que el horno está totalmente enfrió a TA. Nota: Durante 6 hr del proceso de enfriamiento, la velocidad media de enfriamiento del horno por encima de 400 ° C es de ~ 15 ° C / min y la velocidad media de enfriamiento del horno por debajo de 400 ° C es de ~ 2 ° C / min. </li><li> Si es necesario, cortar el bloque de sinterizado poroso Ti en muestras en forma de disco con un diámetro de 16 mm a través de mecanizado por descarga eléctrica (EDM). 27 Nota: Dependiendo del tamaño de los moldes Al, el tamaño de la sinterizado poroso Ti necesita ser modificado a través del proceso de mecanizado (Figura 2A). </li><li> Coloque un vaso de precipitados de vidrio con las muestras porosas Ti en un autoclave y esterilizar las muestras a 121 ° C durante 15 min. Retirar las muestras del autoclave. Lavar las muestras porosas Ti con agua destilada dos veces y luego con etanol al 70% dos veces.Por último, dejar la porosa Ti en una placa de Petri y aire seco de las muestras a temperatura ambiente en un banco limpio bajo la luz ultravioleta. </li></ol> 2. Dip Coating de andamios con agentes bioactivos <ol><li> Diluir el comercial Fluorescencia verde Protein (GFP) a partir de 1 mg / ml a 100 mg / ml en un banco limpio mediante la mezcla de 1 ml de GFP con 9 ml de tampón fosfato salino (DPBS, pH 7,4) solución de Dulbecco en un 10 esterilizan-ml poliestireno (PS) de tubo como se indica en la Tabla 1. </li><li> Sumergir el esterilizada densa o porosa Ti en 10 ml de solución de GFP diluido (100 g / ml) mediante la colocación de las muestras de Ti en el tubo de PS con la solución de GFP a TA y colocación en un banco limpio. </li><li> Colocar el tubo de PS en un desecador de vacío y evacuar el desecador durante 10 min para asegurar la solución GFP penetra en los poros de la porosa Ti con mayor eficacia. </li><li> Retire el titanio poroso del tubo de PS con unas pinzas. Coloque la GFP recubierto poroso Ti en un diámetro de 10 cm Peplato tri y aire seco O / N a temperatura ambiente en un banco limpio. </li><li> Enjuague la porosa Ti dos veces con 10 ml de Dulbecco tampón fosfato salino (DPBS) en un vaso de vidrio, y mover el porosa Ti en una placa de Petri de diámetro 10 cm con unas pinzas y aire seco a temperatura ambiente en un banco limpio. </li></ol> 3. La densificación de andamios porosos <ol><li> Colocar las muestras porosas GFP Ti recubierto con varias alturas en un troquel de acero cilíndrica, e insertar un conjunto de golpes en los orificios superior e inferior de la matriz de acero (Figura 3A). </li><li> Comprimir el porosa Ti dentro del conjunto de troquel de acero a TA en la dirección z de la muestra (Figura 3A) utilizando una máquina de prensa en velocidades de deformación intermedios de 0,05 ~ 0,1 seg -1 contra las cepas aplicadas predeterminados mostrados en la Tabla 2. Mantenga la presión durante 1 minuto antes de la descarga. </li><li> Retire las muestras Ti densificadas de la matriz de acero. Lavar las muestras densificadas dos veces con 10 ml de DPBSen un vaso de precipitados y O-secar al aire / N a temperatura ambiente en un banco limpio. </li></ol> 4. Prueba de Liberación de andamios GFP-revestido <ol><li> Sumergir tres tipos de especímenes (GFP-revestido densa Ti (después de las etapas 2), recubierto GFP-porosa Ti (después de los pasos 1 y 2) y GFP-revestido porosa densificada Ti (después de los pasos 1-3)) en 5 ml DPBS (pH 7.4) solución contenida en un tubo esterilizado PS 10 ml a 37 ° C en un banco limpio. </li><li> Succión toda la solución de DPBS de cada tubo PS con la muestra de GFP-revestido y reponer con una solución de nuevos 5 ml de DPBS (pH 7,4) usando una pipeta de acuerdo con los tiempos predeterminados de 1, 2, 3, 5, 8, 12, 15, 22 y 29 días después de la inmersión. </li><li> Tome las imágenes de fluorescencia de las muestras recubiertas de GFP antes de la inmersión (día 0) y después de 22 días de inmersión usando espectroscopia láser confocal de barrido (CLSM). </li><li> Medir la intensidad de la señal de fluorescencia de la GFP lanzado en 1 ml de solución de un total de 5 ml de solución DPBS extraída de cada tubo de PS en la sección 4.2 utilizandoEspectroscopía UV a una longitud de onda de 215 nm. Convertir el valor de intensidad en la concentración de la solución de GFP usando la curva estándar. Nota: Antes de la medición, dibujar la curva estándar de la solución de GFP mediante la medición de la intensidad de la señal de fluorescencia de la solución de GFP en el intervalo de concentraciones de 0 ng / ml - 10 mg / ml. </li></ol> 5. Fabricación de Graded porosos Ti Andamios <ol><li> Producir un bloque del sinterizado poroso Ti repitiendo el paso 1.1 al paso 1.7. </li><li> El bloque de Ti sinterizado poroso de acuerdo con los diseños de estructura predeterminada (por ejemplo, la Figura 5A y 5D) por EDM Machine. </li><li> Colocar las muestras mecanizadas Ti con distribución de la altura en un troquel de acero, donde el diámetro de Ti porosa es de ~ 0,1 mm menor que el diámetro de la matriz e insertar un conjunto de golpes en los orificios superior e inferior de la matriz de acero. </li><li> Realice los pasos 3.2 y 3.3. </li></ol> 6. La porosidad de míasurement de Ti Andamios <ol><li> Mida la masa (m s) de andamios Ti. </li><li> Calcular el volumen aparente (V s) mediante la medición de la longitud, anchura y altura de andamios Ti. </li><li> Calcular la porosidad usando la siguiente ecuación: <img alt="Ecuación 1" src="/files/ftp_upload/53279/53279eq1.jpg" /> donde P es el porcentaje total de porosidad, ρ Ti es la densidad teórica del titanio y m S / V S es la densidad medida de la muestra. Nota: La porosidad de las muestras de Ti puede ser recuperada directamente de las imágenes después de la impresión microCT microCT se lleva a cabo utilizando un escáner de micro-tomografía computarizada. </li></ol>

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The authors declare that they have no competing financial interests.

Mientras que los sistemas Biometal han sido ampliamente utilizados para aplicaciones biomédicas, sobre todo, como materiales de carga, alta rigidez y baja bioactividad de los metales han sido considerados como los principales desafíos. En este estudio, hemos establecido el método de fabricación de un nuevo sistema de metal, un andamio de metal poroso densificado que tiene propiedades mecánicas biomiméticos, así como con superficie bioactiva comportamiento de liberación sostenible. Las principales ventajas de nue...

Mientras biomateriales metálicos han sido ampliamente utilizados como implantes de soporte de carga y dispositivos de fijación interna, debido a su excelente resistencia mecánica y resistencia a 1-3 que involucran a dos retos críticos: 1) desajuste mecánico porque los metales son mucho más rígidos que los tejidos biológicos, causando daños indeseables a los tejidos circundantes y 2) baja bioactividad que a menudo resulta en pobres interfaz con los tejidos biológicos, a menudo provocan reacciones a cuerpos extraños (por ejemplo, inflamación o trombosis). Se han propuesto 4-6 andamios metálicos porosos para promover el crecimiento óseo en las estructuras, mejorando . contacto hueso-implante mientras que los efectos de escudo de estrés son suprimidos debido a su rigidez reducida 7-9 Además, diversas modificaciones de la superficie se han aplicado para mejorar las actividades biológicas de los implantes metálicos; tales modificaciones incluyen recubrimiento de la superficie metálica con moléculas bioactivas (por ejemplo, fac crecimientores) o drogas (por ejemplo, vancomicina, tetraciclina) 10-12. Sin embargo, los problemas tales como propiedades mecánicas reducidas de andamios metálicos porosos, disminución de la rigidez y la liberación rápida de las capas de recubrimiento bioactivo siguen sin resolverse. 13-16 de En particular, el titanio (Ti) y Ti aleaciones son uno de los sistemas Biometal más populares debido a sus excelentes propiedades mecánicas, estabilidad química, y buena biocompatibilidad. 13,17-19 Sus aplicaciones en forma de espuma también han atraído un interés creciente debido a que el 3D redes porosas promueven el crecimiento óseo, además de propiedades mecánicas similares al hueso. Se han hecho esfuerzos para mejorar 20-22 las propiedades mecánicas mediante el desarrollo de nuevas técnicas de fabricación, incluyendo la replicación de la esponja polimérica, sinterización de partículas de metal, método de creación rápida de prototipos (RP), y espacio método de soporte con el fin de controlar las diversas características de los poros (por ejemplo, la fracción de poros,forma, tamaño, distribución y conectividad) y de las propiedades del material (por ejemplo, la fase metálica y de impurezas). 23-25 ​​Recientemente, el casting congelación de suspensión metálica a base de agua se ha ganado una considerable atención para producir formas Ti mejoradas mecánicamente con poros bien alineada estructuras utilizando el crecimiento de dendritas de hielo durante la solidificación unidireccional; sin embargo, la contaminación de oxígeno causada por el contacto de polvos metálicos con agua requiere un cuidado especial para minimizar la fragilización de los andamios Ti 14,15. Por lo tanto, hemos desarrollado un nuevo enfoque hacia la fabricación de andamios porosos Ti bioactivos y mecánicamente sintonizables. 25 Los andamios inicialmente tienen estructuras porosas con una porosidad de más de 50%. Los andamios porosos fabricados fueron recubiertas con moléculas bioactivas y luego comprimidos usando una prensa mecánica durante el cual la porosidad final, las propiedades mecánicas y el comportamiento de liberación del fármaco se controla mediante la aplicepa ed. Los implantes densificadas Ti porosos han mostrado baja porosidad con una buena resistencia a pesar de la baja rigidez comparable a la del hueso (desde 3 hasta 20 GPa). 2 Debido a la capa de recubrimiento, la bioactividad de la densificado porosa Ti mejoró significativamente. Por otra parte, debido a las estructuras de poros planas únicas inducidas por el proceso de densificación, se observaron las moléculas bioactivas revestidos para ser lanzado gradualmente desde el andamio, manteniendo su eficacia durante un período prolongado. En este estudio, hemos introducido nuestro método establecido para fabricar andamios densificadas Ti porosas para uso potencial en aplicaciones biomédicas. El protocolo incluye la fundición de congelación dinámica con lechadas de metal y densificación de andamios porosos. En primer lugar, para fabricar andamios porosos Ti con buena ductilidad se introdujo el método de colada de congelación dinámica como se muestra en la Figura 1A. Polvo de Ti se dispersó en canfeno líquido; entonces, por la disminución de la temperatura,la fase líquida se solidificó, dando como resultado la separación de fases entre la red de polvo de Ti y canfeno cristales sólidos. Posteriormente, el cuerpo verde solidificado Ti-canfeno se sinterizó en el que polvos de Ti se condensaron con puntales continuos Ti, y la fase canfeno se eliminó completamente para obtener una estructura porosa. Se empleó el revestimiento y proceso de densificación con los andamios porosos obtenidos, variando el grado de densificación y la porosidad inicial. La capa de recubrimiento y su comportamiento de liberación se visualizaron y cuantificaron utilizando la proteína fluorescente verde (GFP) presenta el revestimiento poroso Ti con y sin densificación en comparación con la GFP-revestido densa Ti. Por último, se propusieron y demostraron mediante la variación del grado de densificación de las partes interior y exterior de los andamios porosos andamios Ti funcionalmente graduadas que tienen dos diferentes estructuras porosas.

<table>
	<tbody>
		<tr>
			<td>Titanium powder</td>
			<td>Alfa Aesar</td>
			<td>#42624</td>
			<td>-325 mesh, 99.5% (metals basis)</td>
		</tr>
		<tr>
			<td>Camphene</td>
			<td>SigmaAldrich</td>
			<td>#456055</td>
			<td>95%, C10H16</td>
		</tr>
		<tr>
			<td>KD-4</td>
			<td>Croda</td>
			<td>&#173;</td>
			<td>Hypermer, polymeric dispersant</td>
		</tr>
		<tr>
			<td>Phosphate Buffer Solution (PBS)</td>
			<td>Welgene</td>
			<td>ML 008-01</td>
			<td>&#173;</td>
		</tr>
		<tr>
			<td>Green Fluorescent Protein (GFP)</td>
			<td>Genoss Co.</td>
			<td>-</td>
			<td>&#62;98% purity, 1mg/ml</td>
		</tr>
		<tr>
			<td>Ball mill oven</td>
			<td>SAMHENUG ENERGY</td>
			<td>SH-BDO150</td>
			<td>&#173;</td>
		</tr>
		<tr>
			<td>Freeze dryer</td>
			<td>Ilshin Lab.</td>
			<td>PVTFD50A</td>
			<td>&#173;</td>
		</tr>
		<tr>
			<td>Cold isostatic pressing (CIP) machine</td>
			<td>SONGWON SYSTEMS</td>
			<td>CIP 42260</td>
			<td>&#173;</td>
		</tr>
		<tr>
			<td>Vaccum furnace</td>
			<td>JEONG MIN INDUSTRIAL</td>
			<td>JM-HP20</td>
			<td>&#173;</td>
		</tr>
		<tr>
			<td>electical chaege machine</td>
			<td>FANUC robocut</td>
			<td>0iB</td>
			<td>External use</td>
		</tr>
		<tr>
			<td>Press machine</td>
			<td>CG&#38;S</td>
			<td>AJP-200</td>
			<td>&#173;</td>
		</tr>
		<tr>
			<td>Confocal laser scanning spectroscopy (CLSM)</td>
			<td>Olympus</td>
			<td>FluoView FV1000</td>
			<td>External use</td>
		</tr>
	</tbody>
</table>

fabrication of mechanically tunable and bioactive metal scaffolds for biomedical applications

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification.

El proceso de fabricación utilizado para producir andamios porosos Ti se ilustra en la Figura 1A. Polvo de Ti se mantiene dispersa homogéneamente en canfeno por la rotación continua del recipiente a 44 ° C durante 12 horas y, mientras canfeno líquido se solidifica completamente, ningún sedimentos relativamente pesado polvo de Ti se pueden minimizar. Como resultado, el cuerpo verde homogénea Ti-canfeno fue producido usando el proceso de fundición de congelación dinámica como se muestra ...

Watch this Scientific Journal Video about Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications at JoVE.com

Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications

Bioactive and mechanically reliable metal scaffolds have been fabricated through a method which consists of two processes, dynamic freeze casting for the fabrication of porous Ti, and coating and densification of the Ti scaffolds. The densification process is simple, effective and applicable to the fabrication of functionally graded scaffolds.

Fabricación de Mecánicamente sintonizable y Bioactivos metal andamios para Aplicaciones Biomédicas

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness ...

fabrication-mechanically-tunable-bioactive-metal-scaffolds-for

Research

Education

JoVE Core

JoVE Journal

Mechanical Engineering

Bioengineering

Unit 1

Transformations of Stress and Strain

SCIENTISTS IN ACTION

10.6K vistas.  Korea Institute of Industrial Technology. Bioactive and mechanically reliable metal scaffolds have been fabricated through a method which consists of two processes, dynamic freeze casting for the fabrication of porous Ti, and coating and densification of the Ti scaffolds. The densification process is simple, effective and applicable to the fabrication of functionally graded scaffolds.

Video: Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications

Microfabricated Platforms for Mechanically Dynamic Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

Plataformas microfabricated para el cultivo celular mecánico dinámico

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or ...

Investigación

Bioingeniería

Preparation of 3D Fibrin Scaffolds for Stem Cell Culture Applications

Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche 1. Culturing stem cells inside of 3D biomaterial scaffolds provides a way to accurately mimic these microenvironments, providing an advantage over traditional 2D culture methods using polystyrene as well as a method for engineering replacement tissues 2. While 2D tissue culture polystrene has been used for the majority of cell culture experiments, 3D biomaterial scaffolds can more closely replicate the microenvironments found in vivo by enabling more accurate establishment of cell polarity in the environment and possessing biochemical and mechanical properties similar to soft tissue.3 A variety of naturally derived and synthetic biomaterial scaffolds have been investigated as 3D environments for supporting stem cell growth. While synthetic scaffolds can be synthesized to have a greater range of mechanical and chemical properties and often have greater reproducibility, natural biomaterials are often composed of proteins and polysaccharides found in the extracelluar matrix and as a result contain binding sites for cell adhesion and readily support cell culture. Fibrin scaffolds, produced by polymerizing the protein fibrinogen obtained from plasma, have been widely investigated for a variety of tissue engineering applications both in vitro and in vivo 4. Such scaffolds can be modified using a variety of methods to incorporate controlled release systems for delivering therapeutic factors 5. Previous work has shown that such scaffolds can be used to successfully culture embryonic stem cells and this scaffold-based culture system can be used to screen the effects of various growth factors on the differentiation of the stem cells seeded inside 6,7.
 This protocol details the process of polymerizing fibrin scaffolds from fibrinogen solutions using the enzymatic activity of thrombin. The process takes 2 days to complete, including an overnight dialysis step for the fibrinogen solution to remove citrates that inhibit polymerization. These detailed methods rely on fibrinogen concentrations determined to be optimal for embryonic and induced pluripotent stem cell culture. Other groups have further investigated fibrin scaffolds for a wide range of cell types and applications - demonstrating the versatility of this approach 8-12.

This work details the preparation of 3D fibrin scaffolds for culturing and differentiating plutipotent stem cells. Such scaffolds can be used to screen the effects of various biological compounds on stem cell behavior as well as modified to contain drug delivery systems.

Preparación de fibrina Andamios 3D para Aplicaciones madre para cultivo celular

Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche 1. Culturing stem cells ...

Designing Silk-silk Protein Alloy Materials for Biomedical Applications

Fibrous proteins display different sequences and structures that have been used for various applications in biomedical fields such as biosensors, nanomedicine, tissue regeneration, and drug delivery. Designing materials based on the molecular-scale interactions between these proteins will help generate new multifunctional protein alloy biomaterials with tunable properties. Such alloy material systems also provide advantages in comparison to traditional synthetic polymers due to the materials biodegradability, biocompatibility, and tenability in the body. This article used the protein blends of wild tussah silk (Antheraea pernyi) and domestic mulberry silk (Bombyx mori) as an example to provide useful protocols regarding these topics, including how to predict protein-protein interactions by computational methods, how to produce protein alloy solutions, how to verify alloy systems by thermal analysis, and how to fabricate variable alloy materials including optical materials with diffraction gratings, electric materials with circuits coatings, and pharmaceutical materials for drug release and delivery. These methods can provide important information for designing the next generation multifunctional biomaterials based on different protein alloys.

Blending is an efficient approach to generate biomaterials with a broad range of properties and combined features. By predicting the molecular interactions between different natural silk proteins, new silk-silk protein alloy platforms with tunable mechanical resiliency, electrical response, optical transparency, chemical processability, biodegradability, or thermal stability can be designed.

El diseño de proteínas de seda-seda aleaciones para aplicaciones biomédicas

Fibrous proteins display different sequences and structures that have been used for various applications in biomedical fields such as biosensors, ...

Fabrication of a Bioactive, PCL-based "Self-fitting" Shape Memory Polymer Scaffold

Tissue engineering has been explored as an alternative strategy for the treatment of critical-sized cranio-maxillofacial (CMF) bone defects. Essential to the success of this approach is a scaffold that is able to conformally fit within an irregular defect while also having the requisite biodegradability, pore interconnectivity and bioactivity. By nature of their shape recovery and fixity properties, shape memory polymer (SMP) scaffolds could achieve defect &#8220;self-fitting.&#8221; In this way, following exposure to warm saline (~60 &#186;C), the SMP scaffold would become malleable, permitting it to be hand-pressed into an irregular defect. Subsequent cooling (~37 &#186;C) would return the scaffold to its relatively rigid state within the defect. To meet these requirements, this protocol describes the preparation of SMP scaffolds prepared via the photochemical cure of biodegradable polycaprolactone diacrylate (PCL-DA) using a solvent-casting particulate-leaching (SCPL) method. A fused salt template is utilized to achieve pore interconnectivity. To realize bioactivity, a polydopamine coating is applied to the surface of the scaffold pore walls. Characterization of self-fitting and shape memory behaviors, pore interconnectivity and in vitro bioactivity are also described.

Fabrication of a Bioactive, PCL-based &quot;Self-fitting&quot; Shape Memory Polymer Scaffold

Scaffolds capable of fitting within cranio-maxillofacial (CMF) bone defects while exhibiting osteoconductivity and bioactivity are of interest. This protocol describes the preparation of a shape memory scaffold based on polycaprolactone diacrylate (PCL-DA) using a solvent-casting particulate-leaching (SCPL) method employing a fused salt template and application of a bioactive polydopamine coating.

La fabricación de una memoria de forma &quot;Auto-ajuste&quot; basado en PCL Bioactivos, Polymer Andamios

Tissue engineering has been explored as an alternative strategy for the treatment of critical-sized cranio-maxillofacial (CMF) bone defects. Essential to ...

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial applications. Here we describe how electrospinning or electrospraying a polymer mixture containing a biodegradable, biocompatible aliphatic polyester (e.g., polycaprolactone and poly(lactide-co-glycolide)), as the major component, doped with a hydrophobic copolymer composed of the polyester and a stearate-modified poly(glycerol carbonate) affords a superhydrophobic biomaterial. The fabrication techniques of electrospinning or electrospraying provide the enhanced surface roughness and porosity on and within the fibers or the particles, respectively. The use of a low surface energy copolymer dopant that blends with the polyester and can be stably electrospun or electrosprayed affords these superhydrophobic materials. Important parameters such as fiber size, copolymer dopant composition and/or concentration, and their effects on wettability are discussed. This combination of polymer chemistry and process engineering affords a versatile approach to develop application-specific materials using scalable techniques, which are likely generalizable to a wider class of polymers for a variety of applications.

Two- and three-dimensional superhydrophobic polymeric materials are prepared by electrospinning or electrospraying biodegradable polymers blended with a lower surface energy polymer of similar composition.

Fabricación superhidrófobas materiales poliméricos para aplicaciones biomédicas

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial ...

Fabrication of a Dipole-assisted Solid Phase Extraction Microchip for Trace Metal Analysis in Water Samples

This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water samples. A brief overview of the evolution of chip-based SPE techniques is provided. This is followed by an introduction to specific polymeric materials and their role in SPE. To develop an innovative dipole-assisted SPE technique, a chlorine (Cl)-containing SPE functionality was implanted into a poly(methyl methacrylate) (PMMA) microchip. Herein, diverse analytical techniques including contact angle analysis, Raman spectroscopic analysis, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis were employed to validate the utility of the implantation protocol of the C-Cl moieties on the PMMA. The analytical results of the X-ray absorption near-edge structure (XANES) analysis also demonstrated the feasibility of the Cl-containing PMMA used as an extraction medium by virtue of the dipole-ion interactions between the highly electronegative C-Cl moieties and the positively charged metal ions.

The fabrication protocol of a dipole-assisted solid phase extraction microchip for the trace metal analysis is presented.

La fabricación de un dipolo-asistida en fase sólida para extracción Microchip Análisis de trazas de metales en muestras de agua

This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water ...

Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications

Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest regarding the use of bioinspired nanoscale hydroxyapatite (nHA). However, biological apatite is known to be calcium-deficient and carbonate-substituted with a nanoscale platelet-like morphology. Bioinspired nHA has the potential to stimulate optimal bone tissue regeneration due to its similarity to bone and tooth enamel mineral. Many of the methods currently used to fabricate nHA both in the laboratory and commercially, involve lengthy processes and complex equipment. Therefore, the aim of this study was to develop a rapid and reliable method to prepare high quality bioinspired nHA. The rapid mixing method developed was based upon an acid-base reaction involving calcium hydroxide and phosphoric acid. Briefly, a phosphoric acid solution was poured into a calcium hydroxide solution followed by stirring, washing and drying stages. Part of the batch was sintered at 1,000 &#176;C for 2 h in order to investigate the products&#39; high temperature stability. X-ray diffraction analysis showed the successful formation of HA, which showed thermal decomposition to &#946;-tricalcium phosphate after high temperature processing, which is typical for calcium-deficient HA. Fourier transform infrared spectroscopy showed the presence of carbonate groups in the precipitated product. The nHA particles had a low aspect ratio with approximate dimensions of 50 x 30 nm, close to the dimensions of biological apatite. The material was also calcium deficient with a Ca:P molar ratio of 1.63, which like biological apatite is lower than the stoichiometric HA ratio of 1.67. This new method is therefore a reliable and far more convenient process for the manufacture of bioinspired nHA, overcoming the need for lengthy titrations and complex equipment. The resulting bioinspired HA product is suitable for use in a wide variety of medical and consumer health applications.

This paper describes a novel method for the rapid manufacture of high quality bioinspired nanoscale hydroxyapatite. This biomaterial is of great significance in the manufacture of a wide range of innovative medical devices for clinical applications in orthopedics, craniofacial surgery and dentistry.

Mezcla rápida Preparación de Bioinspirada nanoescala hidroxiapatita para aplicaciones biomédicas

Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest ...

Patterning Bioactive Proteins or Peptides on Hydrogel Using Photochemistry for Biological Applications

There are many biological stimuli that can influence cell behavior and stem cell differentiation. General cell culture approaches rely on soluble factors within the medium to control cell behavior. However, soluble additions cannot mimic certain signaling motifs, such as matrix-bound growth factors, cell-cell signaling, and spatial biochemical cues, which are common influences on cells. Furthermore, biophysical properties of the matrix, such as substrate stiffness, play important roles in cell fate, which is not easily manipulated using conventional cell culturing practices. In this method, we describe a straightforward protocol to provide patterned bioactive proteins on synthetic polyethylene glycol (PEG) hydrogels using photochemistry. This platform allows for the independent control of substrate stiffness and spatial biochemical cues. These hydrogels can achieve a large range of physiologically relevant stiffness values. Additionally, the surfaces of these hydrogels can be photopatterned with bioactive peptides or proteins via thiol-ene click chemistry reactions. These methods have been optimized to retain protein function after surface immobilization. This is a versatile protocol that can be applied to any protein or peptide of interest to create a variety of patterns. Finally, cells seeded onto the surfaces of these bioactive hydrogels can be monitored over time as they respond to spatially specific signals.

In this method, we use photopolymerization and click chemistry techniques to create protein or peptide patterns on the surface of polyethylene glycol (PEG) hydrogels, providing immobilized bioactive signals for the study of cellular responses in vitro.

Patrones bioactivas proteínas o péptidos en hidrogel con fotoquímica para usos biológicos

There are many biological stimuli that can influence cell behavior and stem cell differentiation. General cell culture approaches rely on soluble factors ...

Melt Electrospinning Writing of Three-dimensional Poly(&#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology with great potential for biomedical applications. The technique facilitates the direct deposition of biocompatible polymer fibers to fabricate well-ordered scaffolds in the sub-micron to micro scale range. The establishment of a stable, viscoelastic, polymer jet between a spinneret and a collector is achieved using an applied voltage and can be direct-written. A significant benefit of a typical porous scaffold is a high surface-to-volume ratio which provides increased effective adhesion sites for cell attachment and growth. Controlling the printing process by fine-tuning the system parameters enables high reproducibility in the quality of the printed scaffolds. It also provides a flexible manufacturing platform for users to tailor the morphological structures of the scaffolds to their specific requirements. For this purpose, we present a protocol to obtain different fiber diameters using melt electrospinning writing (MEW) with a guided amendment of the parameters, including flow rate, voltage and collection speed. Furthermore, we demonstrate how to optimize the jet, discuss often experienced technical challenges, explain troubleshooting techniques and showcase a wide range of printable scaffold architectures.

Melt Electrospinning Writing of Three-dimensional Poly(&amp;#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This protocol serves as a comprehensive guideline to fabricate scaffolds via electrospinning with polymer melts in a direct writing mode. We systematically outline the process and define the appropriate parameter settings for achieving targeted scaffold architectures.

Escritura de Electrospinning de andamios Poly(ε-caprolactone) tridimensional con morfologías controlables para aplicaciones de ingeniería de tejidos del derretimiento

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology ...

Fabrication and Characterization of Griffithsin-modified Fiber Scaffolds for Prevention of Sexually Transmitted Infections

Electrospun fibers (EFs) have been widely used in a variety of therapeutic applications; however, they have only recently been applied as a technology to prevent and treat sexually transmitted infections (STIs). Moreover, many EF technologies focus on encapsulating the active agent, relative to utilizing the surface to impart biofunctionality. Here we describe a method to fabricate and surface-modify poly(lactic-co-glycolic) acid (PLGA) electrospun fibers, with the potent antiviral lectin Griffithsin (GRFT). PLGA is an FDA-approved polymer that has been widely used in drug delivery due to its outstanding chemical and biocompatible properties. GRFT is a natural, potent, and safe lectin that possesses broad activity against numerous viruses including human immunodeficiency virus type 1 (HIV-1). When combined, GRFT-modified fibers have demonstrated potent inactivation of HIV-1 in vitro. This manuscript describes the methods to fabricate and characterize GRFT-modified EFs. First, PLGA is electrospun to create a fiber scaffold. Fibers are subsequently surface-modified with GRFT using 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS)chemistry. Scanning electron microscopy (SEM) was used to assess the size and morphology of surface-modified formulations. Additionally, a gp120 or hemagglutinin (HA)-based ELISA may be used to quantify the amount of GRFT conjugated to, as well as GRFT desorption from the fiber surface. This protocol can be more widely applied to fabricate fibers that are surface-modified with a variety of different proteins.

This manuscript describes the procedure to fabricate and characterize Griffithsin-modified poly(lactic-co-glycolic acid) electrospun fibers that demonstrate potent adhesive and antiviral activity against human immunodeficiency virus type 1 infection in vitro. Methods used to synthesize, surface-modify, and characterize the resulting morphology, conjugation, and desorption of Griffithsin from surface-modified fibers are described.

Fabricación y caracterización de andamios de fibra modificado Griffithsin para la prevención de infecciones de transmisión sexual

Electrospun fibers (EFs) have been widely used in a variety of therapeutic applications; however, they have only recently been applied as a technology to ...