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. Fabrication de métal poreux échafaudages <ol><li> Préparer boues Ti-camphène par mélange disponible dans le commerce poudre de Ti, camphène, et KD-4 après avoir pesé les quantités appropriées de matériaux tel que décrit dans le tableau 1 pour les échafaudages Ti poreuses avec quatre porosités initiales (40, 50, 60, et 70). Pour les suspensions dans 500 ml de polyéthylène (PE) et faire pivoter les bouteilles des bouteilles à 55 ° C pendant 30 min dans un four broyeur à boulets à 30 tours par minute. </li><li> Pour les boues provenant des bouteilles en PE en aluminium cylindrique (Al) des moules d&#39;un diamètre de 60 mm et une hauteur de 60 mm. Sceller chaque moule Al à la lamelle Al correspondant et faire pivoter les moules dans un four broyeur à boulets à une vitesse de 30 tours par minute à 55 ° C pendant 10 min. <ol><li> Par la suite, diminuer la température du four broyeur à boulets à 44 ° C, et de façon continue les moules de tourner à une vitesse de 30 tours par minute à la température constante de 44 ° C pendant 12 heures. </li></ol></li><li> Sortez le moule du balmoulin four après la rotation outre les moules à la température ambiante pendant 1 heure pour le processus de refroidissement. Retirez le corps vert titane / camphène solidifié du moule Al en utilisant un plongeur Al. </li><li> Placez le corps vert titane / camphène solidifiée dans un sac en caoutchouc à la main et sceller complètement le sac en caoutchouc en liant la bouche du sac avec une chaîne. Placez le sac en caoutchouc dans le réservoir d&#39;eau d&#39;une pression (CIP) Machine isostatique à froid et d&#39;appliquer une pression isostatique de 200 MPa pendant 10 min. Retirez le corps vert comprimé provenant du sac en caoutchouc. </li><li> Transférer le corps vert Ti-camphène sur un creuset en alumine à la main et placer le creuset dans la machine à lyophilisateur. Lyophiliser le corps vert pour sublimer la phase de camphène dans le corps vert à - 40 ° C pendant 24 heures. </li><li> Par la suite, fermer le creuset avec une lamelle d&#39;alumine et de placer le creuset fermé dans un four sous vide (inférieur à 10 -6 Torr) à température ambiante. Ensuite, augmenter la température du four à 1300 ° C à un chauffage rmangé de 5 ° C / min et maintenir la température à 1300 ° C pendant 2 heures. </li><li> Après le traitement thermique, garder la fritte poreux Ti dans le four pour 7/6 heure jusqu&#39;à ce que le four est complètement refroidi à température ambiante. Remarque: Au cours de six heures de la phase de refroidissement, la vitesse de refroidissement moyenne du four au-dessus de 400 ° C est d&#39;environ 15 ° C / min et la vitesse de refroidissement moyenne de la chaudière au-dessous de 400 ° C est d&#39;environ 2 ° C / min. </li><li> Si nécessaire, couper le bloc de fritté poreux Ti en échantillons en forme de disque d&#39;un diamètre de 16 mm grâce à l&#39;usinage par électroérosion (EDM). 27 Remarque: En fonction de la taille des moules Al, la taille de la fritte poreux Ti doit être modifiée au cours du processus d&#39;usinage (figure 2A). </li><li> Placer un bêcher en verre avec les échantillons poreux Ti dans un autoclave et stériliser les échantillons à 121 ° C pendant 15 min. Retirer les échantillons de l&#39;autoclave. Laver les échantillons Ti poreuses avec de l&#39;eau distillée deux fois et ensuite avec 70% d&#39;éthanol deux fois.Enfin, laissez le Ti poreux dans une boîte de Petri et sécher à l&#39;air les échantillons à température ambiante sur un banc propre sous lumière UV. </li></ol> 2. Plonger Revêtement des échafaudages avec des agents bioactifs <ol><li> Diluer le commercial vert Fluorescence Protein (GFP) de 1 mg / ml à 100 pg / ml dans un banc de nettoyage en mélangeant 1 ml de la GFP avec 9 ml de tampon phosphate salin (DPBS, pH 7,4) la solution de Dulbecco dans un 10 ml stérilisés polystyrène (PS) tube comme indiqué dans le tableau 1. </li><li> Immerger le Ti poreux dense ou stérilisé dans 10 ml de solution diluée de la GFP (100 ug / ml) en plaçant les échantillons de Ti dans le tube de PS avec la solution à la température ambiante de la GFP et la mise sur un banc de nettoyage. </li><li> Placer le tube de PS dans un dessiccateur à vide et évacuer le dessiccateur pendant 10 min pour assurer la GFP solution pénètre dans les pores du Ti poreux de manière plus efficace. </li><li> Retirez le titane poreux du tube de PS en utilisant une pince à épiler. Placer la GFP-Ti poreux revêtu dans un diamètre de 10 cm Peplat tri et sécher à l&#39;air O / N à température ambiante sur un banc propre. </li><li> Rincer le Ti poreuse deux fois avec 10 ml de solution saline tamponnée phosphate de Dulbecco (DPBS) dans un récipient en verre, et déplacer le Ti poreuse dans une boîte de Pétri de diamètre 10 cm en utilisant une pince à épiler et sécher à l&#39;air à température ambiante sur un banc propre. </li></ol> 3. La densification des échafaudages poreux <ol><li> Placer les échantillons Ti poreuses GFP-enduit avec différentes hauteurs dans un moule cylindrique en acier, et insérer un ensemble de coups de poing dans les trous du haut et du bas de la matrice en acier (figure 3A). </li><li> Comprimer le Ti poreux à l&#39;intérieur de l&#39;ensemble de matrice de l&#39;acier à la température ambiante dans la direction z de l&#39;échantillon (figure 3A) en utilisant une machine de presse à des vitesses de déformation intermédiaires de 0,05 ~ 0,1 sec -1 contre les souches appliquées prédéterminées indiquées dans le tableau 2. Maintenir la pression pendant 1 min avant le déchargement. </li><li> Retirer les échantillons Ti densifiées de la matrice de l&#39;acier. Laver deux fois les échantillons densifiées avec 10 ml de DPBSdans un bécher et sécher à l&#39;air O / N à température ambiante sur un banc propre. </li></ol> 4. test de libération d&#39;échafaudages GFP-enduit <ol><li> Immerger trois types de spécimens (GFP revêtu dense Ti (après les étapes 2), GFP-poreux revêtu Ti (après les étapes 1 et 2) et GFP-enduit poreux densifié Ti (étapes 1-3) après) dans 5 ml de DPBS (pH 7,4) solution contenue dans un tube stérilisé PS 10 ml à 37 ° C sur un banc de nettoyage. </li><li> D&#39;aspiration sur toute la solution DPBS à partir de chaque tube de PS avec l&#39;échantillon de GFP-revêtu et à reconstituer avec une solution de nouveaux 5 ml de DPBS (pH 7,4) en utilisant une pipette en fonction des temps prédéterminés de 1, 2, 3, 5, 8, 12, 15, 22 et 29 jours après l&#39;immersion. </li><li> Prendre des images de fluorescence de la GFP des échantillons revêtus avant l&#39;immersion (jour 0) et après 22 jours d&#39;immersion en utilisant la spectroscopie à balayage laser confocal (CLSM). </li><li> Mesurer l&#39;intensité du signal de fluorescence de la GFP sorti en 1 ml de solution sur un total de 5 ml de solution DPBS tirée de chaque tube de PS dans la section 4.2 à l&#39;aideSpectroscopie UV à une longueur d&#39;onde de 215 nm. Autre la valeur d&#39;intensité dans la concentration de la solution de la GFP en utilisant la courbe standard. Remarque: Avant la mesure, établir la courbe d&#39;étalonnage de la solution de GFP par mesure de la fluorescence d&#39;intensité de signal de la solution de la GFP dans la gamme de concentration de 0 ng / ml - 10 ng / ml. </li></ol> 5. Fabrication de gradués poreux Ti échafaudages <ol><li> Produire un bloc de la fritte poreux Ti en répétant l&#39;étape 1.1 à l&#39;étape 1.7. </li><li> La machine le bloc fritté Ti poreuse selon les conceptions de structure prédéterminée (par exemple, la figure 5a et 5d) par EDM. </li><li> Placer les échantillons Ti usinées avec une distribution de taille dans une matrice en acier dont le diamètre poreux de Ti est d&#39;environ 0,1 mm plus petit que le diamètre de la filière et insérer un jeu de poinçons dans les trous supérieur et inférieur de la matrice de l&#39;acier. </li><li> Effectuer les étapes 3.2 et 3.3. </li></ol> 6. La porosité de moiasurement de Ti échafaudages <ol><li> Mesurer la masse (m s) d&#39;échafaudages Ti. </li><li> Calculer le volume apparent (V s) par la mesure de longueur, la largeur et la hauteur des échafaudages Ti. </li><li> Calculer la porosité en utilisant l&#39;équation suivante: <img alt="Equation 1" src="/files/ftp_upload/53279/53279eq1.jpg" /> où P est le pourcentage total de porosité, ρ est la densité Ti théorique du titane et m S / V S est la densité mesurée de l&#39;échantillon. Remarque: La porosité d&#39;échantillons de Ti peut être récupéré directement à partir des images microCT après microCT imagerie est effectuée en utilisant un scanner de tomographie assistée par micro-calculée. </li></ol>

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The authors declare that they have no competing financial interests.

Alors que les systèmes biométaux ont été largement utilisés pour des applications biomédicales, en particulier, en tant que matériaux porteurs, une rigidité élevée et une faible bioactivité des métaux ont été considérées comme des défis majeurs. Dans cette étude, nous avons établi la méthode de fabrication d&#39;un nouveau système de métal, un échafaudage métallique poreuse densifiée qui a des propriétés mécaniques biomimétiques ainsi que surface bioactive avec le comportement de libération...

Alors que biomatériaux métalliques ont été largement utilisés comme implants porteurs et dispositifs de fixation interne en raison de leur excellente résistance mécanique et de la résilience, 1-3 ils impliquent deux défis essentiels: 1) inadéquation mécanique parce que les métaux sont beaucoup plus rigides que les tissus biologiques, causant des dommages indésirables aux tissus environnants et 2) à faible bioactivité qui aboutit souvent à une mauvaise interface avec les tissus biologiques, provoquant souvent des réactions de corps étranger (par exemple, une inflammation ou thrombose). 4-6 échafaudages métalliques poreux ont été proposées pour favoriser la croissance osseuse dans les structures, l&#39;amélioration . contact os-implant tandis que les effets du stress de blindage sont supprimées en raison de leur rigidité réduite 7-9 En outre, diverses modifications de surface ont été appliquées pour améliorer les activités biologiques des implants métalliques; de telles modifications comprennent le revêtement de la surface métallique avec des molécules bioactives (par exemple, croissance de facteurs) ou des médicaments (par exemple, la vancomycine, la tétracycline). 10-12 Cependant, des problèmes tels que les propriétés mécaniques réduites des échafaudages métalliques poreux, ont diminué la rigidité et la libération rapide des couches de revêtement bioactif restent en suspens. 13-16 En particulier, le titane (Ti) et Ti alliages sont l&#39;un des systèmes les plus populaires biométaux raison de leurs excellentes propriétés mécaniques, la stabilité chimique et une bonne biocompatibilité. 13,17-19 Leurs applications en forme de mousse ont également attiré l&#39;intérêt croissant parce que la 3D réseaux poreux promouvoir la croissance osseuse en plus des propriétés mécaniques des os ressemblant. 20-22 efforts ont été faits pour améliorer les propriétés mécaniques en développant de nouvelles techniques de fabrication, y compris la réplication de l&#39;éponge polymère, le frittage des particules métalliques, prototypage rapide méthode (RP), et Procédé espace de maintien afin de commander les différentes caractéristiques des pores (par exemple, la fraction de pores,forme, la taille, la distribution, et de connectivité) et les propriétés des matériaux (par exemple, la phase métallique et impuretés). 23-25 ​​Récemment, la coulée de gel de la suspension métallique à base d&#39;eau a gagné une attention considérable pour produire mécaniquement améliorés formes Ti avec pores bien aligné structures en utilisant la croissance de dendrites de glace lors de la solidification unidirectionnelle; Cependant, la contamination de l&#39;oxygène causée par le contact de poudres métalliques avec de l&#39;eau nécessite des soins particuliers afin de minimiser la fragilisation des échafaudages Ti 14,15. Par conséquent, nous avons développé une nouvelle approche de la fabrication des échafaudages Ti poreuses bioactifs et mécaniquement accordables. 25 Les échafaudages ont initialement structures poreuses avec une porosité de plus de 50%. Les supports poreux fabriqués ont été revêtues avec des molécules bioactives et ensuite compressés en utilisant une presse mécanique au cours de laquelle la porosité finale, les propriétés mécaniques et le comportement de libération de médicament ont été contrôlés par l&#39;applisouche éd. Les implants Ti poreuses densifiées ont montré une faible porosité avec une bonne résistance malgré la faible rigidité comparable à celle de l&#39;os (3-20 GPa). 2 En raison de la couche de revêtement, la bioactivité de la poreuse densifiée Ti a été significativement améliorée. En outre, en raison des structures uniques de pores plates induites par le processus de densification, les molécules bioactives revêtus ont été vus pour être progressivement libéré à partir de l&#39;échafaudage, en conservant leur efficacité pendant une période prolongée. Dans cette étude, nous avons présenté notre méthode établie pour fabriquer des échafaudages Ti poreuses densifiées pour utilisation potentielle dans des applications biomédicales. Le protocole comprend la coulée de congélation dynamique avec des boues de métaux et la densification des supports poreux. Tout d&#39;abord, pour fabriquer des échafaudages Ti poreuses avec une bonne ductilité du procédé de congélation de coulée dynamique a été présenté comme le montre la figure 1A. Poudre de Ti a été dispersé dans camphène liquide; ensuite, en diminuant la température,la phase liquide est solidifié, ce qui entraîne la séparation de phase entre le réseau de poudre de Ti et de camphène cristaux solides. Par la suite, le corps vert solidifié Ti-camphène a été frittée dans laquelle les poudres de Ti ont été condensés avec des entretoises continues Ti, et la phase de camphène a été complètement éliminé pour obtenir une structure poreuse. Le revêtement et le processus de densification avec les supports poreux obtenus ont été utilisés, en faisant varier le degré de densification et de la porosité initiale. La couche de revêtement et de son comportement de libération ont été visualisés et quantifiés en utilisant la protéine fluorescente verte (GFP) doté d&#39;un revêtement poreux Ti avec et sans densification par rapport à la GFP-Ti revêtu dense. Enfin, les échafaudages Ti fonctionnellement gradués qui ont deux structures poreuses différentes ont été proposées et mises en évidence par la variation de degré de densification des parties interne et externe de l&#39;échafaudage poreux.

<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.

Le procédé de fabrication utilisé pour produire des échafaudages Ti poreux est illustré sur la Figure 1A. Poudre de Ti est maintenu dispersé de façon homogène dans camphène par rotation continue du récipient à 44 ° C pendant 12 heures et, tout en camphène liquide est complètement solidifié, des sédiments de poudre de Ti relativement lourde peuvent être minimisés. En conséquence, le corps vert homogène Ti-camphène a été produit en utilisant le procédé dynamique gel de coulée com...

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.

Fabrication de mécanique accordable et bioactifs Métal échafaudages pour des applications biomédicales

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 vues.  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.

Vidéo: 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.

Plates-formes pour la culture cellulaire microfabriqués mécanique dynamique

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

Recherche

Bio-ingénierie

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.

Préparation de la 3D pour les applications de fibrine Échafaudages CULTURE DE CELLULES SOUCHES

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.

Concevoir protéines de soie soie Matériaux alliage pour applications biomédicales

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.

Fabrication d&#39;une mémoire de forme &quot;auto-ajustement&quot; à base de PCL bioactifs, Polymer Échafaudages

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.

Superhydrophobes fabrication de matériaux polymères pour des applications biomédicales

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.

Fabrication d&#39;une extraction en phase solide Microchip Dipole-assistée pour analyse de traces métalliques dans des échantillons d&#39;eau

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.

Mix rapide Préparation de bioinspirée Nanoscale hydroxyapatite pour applications biomédicales

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.

Structuration des protéines bioactives ou Peptides sur Hydrogel utilisant photochimie pour Applications biologiques

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.

Faire fondre électrofilage écrit d’échafaudages Poly(ε-caprolactone) en trois dimensions avec des Morphologies contrôlables pour les Applications de génie tissulaire

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.

Fabrication et caractérisation des échafaudages de fibre Griffithsin modifiés pour la prévention des Infections sexuellement transmissibles

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