Diese Studie wurde unterstützt durch GreenPAC Polymer-Antrags-Zentrum im Rahmen des Projekts 140413: "3D Druck in der Produktion". Wir würden gerne Albert Hartman, Corinne van Noordenne anerkennen, Rens van Leeuwen, Anniek Bruins, Femke Tamminga, Jur van Dijken und Albert Woortman zur Erleichterung der video-Aufnahmen.

Achtung: Bitte konsultieren Sie alle relevanten Sicherheitsdatenblätter (SDB) vor dem Gebrauch.
1. Vorbereitung des lichthärtenden Harz
Hinweis: Verwenden Sie persönlichen Schutzausrüstung (Schutzbrille, Handschuhe, Kittel) während der folgenden Prozedur. In diesem Abschnitt entnehmen Sie unserer bisherigen Arbeit12 Näheres.
<ol><li>Gießen Sie 50 g 1,10-Decanediol Diacrylate (SA5201) in einen 500-mL-Erlenmeyerkolben.</li>
	<li>Fügen Sie 1,0 g diphenyl(2,4,6-trimethylbenzoyl) phosphin-Oxid (TPO) und 0,40 g 2,5 -BIZ(5 -Tert-Butyl-Benzoxazol-2-Yl) Thiophen (BBOT) in den Kolben.</li>
	<li>Ausrüsten des Kolbens mit einem mechanischen Rührwerk und rühren Sie die Mischung bei 200 u/min für 5 min bei Raumtemperatur um TPO und BBOT in das Acrylat-Monomer aufzulösen.</li>
	<li>Geben Sie 100 g Pentaerythritol-Tetraacrylate und 100 g multifunktionale Epoxy-Acrylat (siehe Tabelle der Materialien), die Mischung.</li>
	<li>Rühren Sie die Mischung bei 200 u/min für 30 min bei 50 ° C zu eine homogenere Harz zu gewährleisten.</li>
	<li>Die mechanische Rührer entfernen und einsetzen des Kolbens mit einem stopfen. Der Kolben ist verpackt in Alufolie um den biobasierten Acrylat Photopolymer Harz (BAPR) vor Licht zu schützen. Hinweis: Das Protokoll kann hier angehalten werden.</li>
	<li>Decken Sie die Bodenplatte ein Rheometer mit Parallel-Plattengeometrie mit der Photoresin.</li>
	<li>Abstand zwischen den Platten bei 1 mm einstellen und dem Rheometer mit UV beständig Kapuze zu decken.</li>
	<li>Messen Sie die Harz-Viskosität bei Raumtemperatur bei Scherraten von 0,1 bis 100 s-1; z. B.0,100, 0.126, 0.158, 0.200, 0,251, 0.316, 0.398, 0.501, 0.631, 0.794, 1,00, 1.26, 1,58, 2.00, 2,51, 3.16, 3,98, 5.01, 6.31, 7.94, 10.0, 12,6, 15,8, 20,0, 25.1, 31,6, 39,8, 50,1, 63,1, 79,4, und 100 s-1.</li>
</ol>(2) Köraform 3D-Druck mit biobasierten Acrylaten
Hinweis: Siehe unsere bisherige Arbeit12 für weitere Details auf diesem Abschnitt.
<ol><li>Schalten Sie die SLA-3D-Drucker und wählen Sie öffnen Modus.</li>
	<li>Starten Sie die Modell-Vorbereitung-Software auf einem Computer. Wählen Sie die gewünschten Druckeinstellungen: Material (klar), Version (V4) und Schichtdicke (50 µm).</li>
	<li>Öffnen Sie das digitale Modell des Prototyps komplex geformten, eine standard tesselation-Sprachdatei (STL) (siehe Zusätzliche Codierung Datei) und wählen Sie die Position und Ausrichtung auf der Bauplattform.  Laden Sie den Druckauftrag aus der Modell-Software zur Vorbereitung auf die SLA-3D-Drucker. Hinweis: Abhängig von der Architektur des Produkts eine Unterstützungsstruktur im 3D-Modell, das Konstrukt während der Fertigung zu stabilisieren sind integrierbar. Im Falle der komplex geformten Prototyp demonstriert hier ist eine Unterkonstruktion nicht erforderlich, wenn senkrecht zur Build gedruckt.</li>
	<li>Gießen Sie 200 mL von biobasierten Photoresin in einem Harz-Tank. Öffnen Sie den 3D Drucker und montieren Sie die Harz-Tank ordnungsgemäß zu.</li>
	<li>Montieren Sie der Bauplattform und schließen Sie den 3D Drucker.</li>
	<li>Starten Sie den Druckauftrag.</li>
	<li>Lassen Sie den 3D Drucker komplex geformte Prototypen herzustellen.  Öffnen Sie den Drucker nicht, bis der Druckauftrag abgeschlossen ist. Hinweis: Vor dem Drucken, stellen Sie sicher, dass der 3D-Drucker abgeglichen wird. Für die nachgewiesene Protokoll ist die Wellenlänge der UV-Laser 405 nm. Die Druckzeit des Objekts beträgt 2,5 h.</li>
</ol>3. Nachbehandlung von 3D Objekten gedruckt
Hinweis: Verwenden Sie persönlichen Schutzausrüstung (Schutzbrille, Handschuhe) während der folgenden Prozedur.
<ol><li>Wenn der Druckauftrag abgeschlossen ist, öffnen Sie den Drucker. Entfernen Sie die Bauplattform mit der produzierten Teile befestigt, und schließen Sie den Drucker.</li>
	<li>Öffnen Sie die Waschstation, gefüllt mit Isopropyl-Alkohol, und fügen Sie der Bauplattform. Starten Sie das Verfahren und die Spülung für 20 min, kein umgesetztes Harz zu entfernen.</li>
	<li>Wenn die Spülung Verfahren abgeschlossen ist, entfernen Sie die Bauplattform aus der Waschanlage und lösen Sie die Prototypen aus der Bauplattform.</li>
	<li>Lassen Sie die Prototypen in die Luft für 30 min trocknen. In der Zwischenzeit Backofen Sie den UV bei 60 ° C. Hinweis: Vorheizen dauert mindestens 15 Minuten. Die UV-Wellenlänge des Ofens beträgt 405 nm, identisch mit der Wellenlänge des Lasers SLA.</li>
	<li>Öffnen Sie den UV-Backofen und schnell die Prototypen auf die sich drehende Plattform. Schließen Sie die UV-Ofen und Heilung für 60 min bei 60 ° C, um die vollständige Umwandlung zu gewährleisten.</li>
	<li>Wenn die Post-heilende Verfahren abgeschlossen ist, öffnen Sie den UV-Backofen und nehmen Sie die Prototypen.</li>
</ol>4. Charakterisierung der Oberflächenmorphologie von komplex geformten Prototypen
Hinweis: Siehe unsere bisherige Arbeit12 für weitere Details auf diesem Abschnitt.
<ol><li>Schneiden Sie ca. 1 cm interne Helix vom komplex geformte Prototyp mit einer Rasierklinge.</li>
	<li>Der Probenhalter mit Doppel doppelseitigen Kohlenstoff leitfähige Band Probe zuordnen.</li>
	<li>Vor der Bildgebung, Mantel die Probe mit 30 nm Pt/Pd (80: 20) auf eine Sputteranlage.</li>
	<li>Legen Sie die Probe in ein Raster-Elektronenmikroskop mit einer Beschleunigungsspannung von 5 kV. Erwerben Sie mehrere Bilder der Probe bei 30 X und 120 X Vergrößerung.</li>
</ol>

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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+3D+printing+of+biomaterials.">Recent advances in 3D printing of biomaterials.</a> Journal of Biological Engineering. 9, 4 (2015).</li><li>Mechels, F. P. W., Feijen, J., Grijpma, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+on+stereolithography+and+its+applications+in+biomedical+engineering.">A review on stereolithography and its applications in biomedical engineering.</a> Biomaterials. 31, 6121-6130 (2010).</li><li>Skoog, S. A., Goering, P. L., Narayan, R. 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C., Schwentenwein, M., Gorsche, C., Stampfl, J., Liska, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toughening+of+photo-curable+polymer+networks:+A+review.">Toughening of photo-curable polymer networks: A review.</a> Polymer Chemistry. 7, 257-286 (2016).</li><li>Miao, S., Zhu, W., Castro, N. J., Nowicki, M., Zhou, X., Cui, H., Fisher, J. P., Zhang, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=4D+printing+smart+biomedical+scaffolds+with+novel+soybean+oil+epoxidized+acrylate.">4D printing smart biomedical scaffolds with novel soybean oil epoxidized acrylate.</a> Scientific Reports. 6, 27226 (2016).</li><li>Voet, V. S. D., Strating, T., Schnelting, G. H. M., Dijkstra, P., Tietema, M., Xu, J., Woortman, A. J. 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C., Liska, R., Stampfl, J., Gurr, M., M&#252;lhaupt, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymers+for+3D+Printing+and+Customized+Additive+Manufacturing.">Polymers for 3D Printing and Customized Additive Manufacturing.</a> Chemical Reviews. 117, 10212-10290 (2017).</li><li>Weng, Z., Zhou, Y., Lin, W., Senthil, T., Wu, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure-property+relationship+of+nano+enhanced+stereolithography+resin+for+desktop+SLA+3D+printer.">Structure-property relationship of nano enhanced stereolithography resin for desktop SLA 3D printer.</a> Composites: Part A. 88, 234-242 (2016).</li><li>Scalera, F., Esposito Corcione, C., Montagna, F., Sannino, A., Maffezzoli, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+characterization+of+UV+curable+epoxy/hydroxyapatite+suspensions+for+stereolithography+applied+to+bone+tissue+engineering.">Development and characterization of UV curable epoxy/hydroxyapatite suspensions for stereolithography applied to bone tissue engineering.</a> Ceramics International. 40, 15455-15462 (2014).</li><li>Lee, H., Fang, N. 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Die Autoren haben nichts preisgeben.

Additiver Fertigung wird bei der Herstellung von maßgeschneiderten Prototypen und Kleinserien, angewendet, wenn die höheren Produktionskosten pro Teil mit herkömmlichen Verfahren konkurrieren können, da gibt es keine Notwendigkeit für die Herstellung von Formen und Werkzeugen. In den letzten zehn Jahren haben die Einnahmen aus Dienstleistungen und Produkte rund um die additive Fertigung13exponentiell gewachsen. Der größte Teil der materiellen Umsatz ist von Photopolymeren. Das Wachstum für...

Rapid-Prototyping bedarfsgesteuerte Produktion und Design-Freiheit ermöglicht und erlaubt, dass die effiziente Herstellung von 3D in einer Schicht für Schicht Weise1konstruiert. Infolgedessen hat 3D-Druck als Herstellung Technik schnell in den letzten Jahren2entwickelt. Verschiedene Technologien zur Verfügung, alle unter Berufung auf die Übersetzung von virtuellen Modellen in physische Objekte und Prozesse wie z. B. Extrusion, direkte Energie Ablagerung, Pulver Erstarrung, Blatt Laminieren und Photopolymerisation anwenden. Dieser umfasst schrittweise UV-Härtung von flüssigen Photopolymer-Harzen. Im Jahr 1986 entwickelt Rumpf und Kollegen Vorrichtung Stereolithographie (SLA), ein UV-Laser-basierten 3D Drucker. In jüngerer Zeit, ein ähnlicher Prozess namens digital Light processing (DLP) verfügbar geworden sind, in welche Photopolymerisation durch ein Lichtprojektor initiiert wird. Zusammen, sind DLP und SLA Stereolithografie 3D Druck3genannt.
SLA ist in hoher Auflösung Prototyping und Fertigung von biomedizinischer Geräte4,5angewendet. Diese Technologie ist besser als weit verbreitete fused Deposition modeling (FDM) in Bezug auf Genauigkeit, Oberflächenveredelung und Auflösung6. Je nach Architektur des Produkts ist eine Unterstützungsstruktur im 3D-Modell, das Konstrukt zu stabilisieren während der Fertigung integriert. Darüber hinaus ist eine Post-Druck Behandlung der hergestellten Teile erforderlich7,8. In der Regel gedruckte Objekte werden in einem Alkohol-Bad aufzulösen nicht umgesetztes Harz gewaschen und anschließende Aushärtung im Backofen UV wird durchgeführt, um die vollständige Umwandlung der Polymerisation9zu gewährleisten.
Im Allgemeinen setzen Harze für Lithographie-basierte additive Fertigung auf lichthärtenden Systeme mit multifunktionalen Acrylaten oder Epoxide10. Aktuelle Photopolymer-Harze auf dem kommerziellen Markt sind fossile und teuer, während die Verfügbarkeit von kostengünstigen erneuerbare Harze benötigt wird, um abfallfreie und lokale Herstellung von nachhaltigen 3D-Produkte für einen biobasierten Wirtschaft1 zu erleichtern , 6. vor kurzem Photopolymer Harze basierend auf erneuerbaren Acrylaten entwickelt und erfolgreich in Stereolithographie 3D Druck11,12angewendet wurden. In diesem ausführlichen Protokoll zeigen wir das rapid Prototyping mit biobasierten Harzen auf einem kommerziellen Stereolithographie-Apparat. Besonderes Augenmerk ist zu kritischen Schritte des Verfahrens, d. h. Harz Formulierung und Post-Drucken-Behandlungen, neue Praktiker im Bereich der additiven Fertigung helfen.

<table><tbody><tr><td>Isobornyl acrylate&amp;nbsp;</td><td>Sartomer</td><td>SA5102</td><td>Acrylate monomer</td></tr><tr><td>1,10-decanediol diacrylate</td><td>Sartomer</td><td>SA5201</td><td>Acrylate monomer</td></tr><tr><td>Pentaerythritol tetraacrylate</td><td>Sartomer</td><td>SA5400</td><td>Acrylate monomer</td></tr><tr><td>Multifunctional epoxy acrylate</td><td>Sartomer</td><td>SA7101</td><td>Acrylate oligomer</td></tr><tr><td>Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), 97%</td><td>Sigma Aldrich</td><td>415952</td><td>Photoinitiator</td></tr><tr><td>2,5-bis(5-&lt;em&gt;tert&lt;/em&gt;-butyl-benzoxazol-2-yl)thiophene (BBOT), 99%</td><td>Sigma Aldrich</td><td>223999</td><td>Optical absorber</td></tr><tr><td>Isopropyl alcohol (IPA), 99%</td><td>Bleko</td><td>1010500</td><td>For alcohol bath (applied in Form Wash)</td></tr><tr><td>Paar Physica MCR300&amp;nbsp;</td><td>Anton Paar</td><td>-</td><td>Rheometer with parallel plate geometry</td></tr><tr><td>Form 2 Printer</td><td>Formlabs</td><td>-</td><td>Desktop SLA 3D printer</td></tr><tr><td>Form Wash&amp;nbsp;</td><td>Formlabs</td><td>-</td><td>Washing station</td></tr><tr><td>Form Cure</td><td>Formlabs</td><td>-</td><td>UV oven</td></tr><tr><td>Instron 4301 1KN Series IX</td><td>Instron</td><td>-</td><td>Universal testing machine</td></tr><tr><td>Philips XL30 ESEM-FEG&amp;nbsp;</td><td>Philips</td><td>-</td><td>Scanning electron microscope</td></tr></tbody></table>

stereolithographic 3d printing with renewable acrylates

Die Zugänglichkeit der kostengünstige erneuerbare Materialien und deren Anwendung bei der additiven Fertigung ist für eine effiziente biobasierten Wirtschaft unerlässlich. Wir demonstrieren das rapid Prototyping von nachhaltigen Harzen mit einem köraform 3D-Drucker. Harz-Formulierung erfolgt durch einfache Vermischung von biobasierten Acrylat-Monomere und Oligomere mit Photoinitiatior und optischen Absorber. Harz-Viskosität wird gesteuert durch das Monomer Oligomer-Verhältnis und wird als Funktion der Schergeschwindigkeit durch ein Rheometer mit parallelen Plattengeometrie bestimmt. Ein köraform Apparat aufgeladen mit den biobasierten Harzen wird eingesetzt, um komplex geformte Prototypen mit hoher Genauigkeit zu fertigen. Die Produkte erfordern eine Nachbehandlung, einschließlich Alkohol spülen und UV-Bestrahlung, um vollständige Heilung zu gewährleisten. Die hohe Funktion Auflösung und hervorragende Oberflächenbearbeitung der Prototypen wird aufgedeckt durch Rasterelektronenmikroskopie.

Vier Vertreter Harz Kompositionen sind in Tabelle 1, zusammen mit ihre durchschnittliche biobasierten Kohlenstoffgehalt (BC) abgeleitet von den einzelnen BC der Komponenten angezeigt. Die Viskosität des Harzes (Abbildung 1) wird durch das Verhältnis von Acrylat-Monomere und Oligomere beeinflusst und in der Regel zeigt Newtonsches Verhalten. Die mechanischen Eigenschaften der Teile, die aus verschiedenen Harzen hergestellt wurden durch Belas...

Watch this Scientific Journal Video about Stereolithographic 3D Printing with Renewable Acrylates at JoVE.com

Stereolithographic 3D Printing with Renewable Acrylates

Ein Protokoll für additive Fertigung mit erneuerbaren Photopolymer Harzen auf einem Stereolithographie-Apparat wird vorgestellt.

Köraform 3D-Druck mit erneuerbaren Acrylaten

The accessibility of cost-competitive renewable materials and their application in additive manufacturing is essential for an efficient biobased economy. ...

stereolithographic-3d-printing-with-renewable-acrylates

Research

JoVE Journal

Chemistry

9.4K Aufrufe.  NHL Stenden University of Applied Sciences. Ein Protokoll für additive Fertigung mit erneuerbaren Photopolymer Harzen auf einem Stereolithographie-Apparat wird vorgestellt.

Serie: Stereolithographic 3D Printing with Renewable Acrylates

3D Printing of Biomolecular Models for Research and Pedagogy

The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D structures are most often perceived using the two-dimensional and exclusively visual medium of the computer screen. Converting digital 3D molecular data into real objects enables information to be perceived through an expanded range of human senses, including direct stereoscopic vision, touch, and interaction. Such tangible models facilitate new insights, enable hypothesis testing, and serve as psychological or sensory anchors for conceptual information about the functions of biomolecules. Recent advances in consumer 3D printing technology enable, for the first time, the cost-effective fabrication of high-quality and scientifically accurate models of biomolecules in a variety of molecular representations. However, the optimization of the virtual model and its printing parameters is difficult and time consuming without detailed guidance. Here, we provide a guide on the digital design and physical fabrication of biomolecule models for research and pedagogy using open source or low-cost software and low-cost 3D printers that use fused filament fabrication technology.

Physical models of biomolecules can facilitate an understanding of their structure-function for the researcher, aid in communication between researchers, and serve as an educational tool in pedagogical endeavors. Here, we provide detailed guidance for the 3D printing of accurate models of biomolecules using fused filament fabrication desktop 3D printers.

3D Printing of Biomolecular Modelle für Forschung und Pädagogik

The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D ...

Forschung

Ingenieurwesen

Human Cartilage Tissue Fabrication Using Three-dimensional Inkjet Printing Technology

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and regenerative medicine. With digital control&#160;cells, scaffolds, and growth factors can be precisely deposited to the desired two-dimensional (2D) and three-dimensional (3D) locations rapidly. Therefore, this technology is an ideal approach to fabricate tissues mimicking their native anatomic structures. In order to engineer cartilage with native zonal organization, extracellular matrix composition (ECM), and mechanical properties, we developed a bioprinting platform using a commercial inkjet printer with simultaneous photopolymerization capable for 3D cartilage tissue engineering. Human chondrocytes suspended in poly(ethylene glycol) diacrylate (PEGDA) were printed for 3D neocartilage construction via layer-by-layer assembly. The printed cells were fixed at their original deposited positions, supported by the surrounding scaffold in simultaneous photopolymerization. The mechanical properties of the printed tissue were similar to the native cartilage. Compared to conventional tissue fabrication, which requires longer UV exposure, the viability of the printed cells with simultaneous photopolymerization was significantly higher. Printed neocartilage demonstrated excellent glycosaminoglycan (GAG) and collagen type II production, which was consistent with gene expression. Therefore, this platform is ideal for accurate cell distribution and arrangement for anatomic tissue engineering.

The methods described in this paper show how to convert a commercial inkjet printer into a bioprinter with simultaneous UV polymerization. The printer is capable of constructing 3D tissue structure with cells and biomaterials. The study demonstrated here constructed a 3D neocartilage.

Menschliches Knorpelgewebe Herstellung unter Verwendung von dreidimensionalen Inkjet-Drucktechnologie

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and ...

Biotechnik

Printing Thermoresponsive Reverse Molds for the Creation of Patterned Two-component Hydrogels for 3D Cell Culture

Bioprinting is an emerging technology that has its origins in the rapid prototyping industry. The different printing processes can be divided into contact bioprinting1-4 (extrusion, dip pen and soft lithography), contactless bioprinting5-7 (laser forward transfer, ink-jet deposition) and laser based techniques such as two photon photopolymerization8. It can be used for many applications such as tissue engineering9-13, biosensor microfabrication14-16 and as a tool to answer basic biological questions such as influences of co-culturing of different cell types17. Unlike common photolithographic or soft-lithographic methods, extrusion bioprinting has the advantage that it does not require a separate mask or stamp. Using CAD software, the design of the structure can quickly be changed and adjusted according to the requirements of the operator. This makes bioprinting more flexible than lithography-based approaches.
Here we demonstrate the printing of a sacrificial mold to create a multi-material 3D structure using an array of pillars within a hydrogel as an example. These pillars could represent hollow structures for a vascular network or the tubes within a nerve guide conduit. The material chosen for the sacrificial mold was poloxamer 407, a thermoresponsive polymer with excellent printing properties which is liquid at 4 &deg;C and a solid above its gelation temperature ~20 &deg;C for 24.5% w/v solutions18. This property allows the poloxamer-based sacrificial mold to be eluted on demand and has advantages over the slow dissolution of a solid material especially for narrow geometries. Poloxamer was printed on microscope glass slides to create the sacrificial mold. Agarose was pipetted into the mold and cooled until gelation. After elution of the poloxamer in ice cold water, the voids in the agarose mold were filled with alginate methacrylate spiked with FITC labeled fibrinogen. The filled voids were then cross-linked with UV and the construct was imaged with an epi-fluorescence microscope.

A bioprinter was used to create patterned hydrogels based on a sacrificial mold. The poloxamer mold was backfilled with a second hydrogel and then eluted, leaving voids which were filled with a third hydrogel. This method uses fast elution and good printability of poloxamer to generate complex architectures from biopolymers.

Drucken Thermoresponsive Reverse-Formen für die Erstellung von Gemusterte Zweikomponenten-Hydrogele für 3D Zellkultur

Bioprinting is an emerging technology that has its origins in the rapid prototyping industry. The different printing processes can be divided into contact ...

Immunologie und Infektion

Three-dimensional Biomimetic Technology: Novel Biorubber Creates Defined Micro- and Macro-scale Architectures in Collagen Hydrogels

Tissue scaffolds play a crucial role in the tissue regeneration process. The ideal scaffold must fulfill several requirements such as having proper composition, targeted modulus, and well-defined architectural features. Biomaterials that recapitulate the intrinsic architecture of in vivo tissue are vital for studying diseases as well as to facilitate the regeneration of lost and malformed soft tissue. A novel biofabrication technique was developed which combines state of the art imaging, three-dimensional (3D) printing, and selective enzymatic activity to create a new generation of biomaterials for research and clinical application. The developed material, Bovine Serum Albumin rubber, is reaction injected into a mold that upholds specific geometrical features. This sacrificial material allows the adequate transfer of architectural features to a natural scaffold material. The prototype consists of a 3D collagen scaffold with 4 and 3 mm channels that represent a branched architecture. This paper emphasizes the use of this biofabrication technique for the generation of natural constructs. This protocol utilizes a computer-aided software (CAD) to manufacture a solid mold which will be reaction injected with BSA rubber followed by the enzymatic digestion of the rubber, leaving its architectural features within the scaffold material.

An innovative biofabrication technique was developed to engineer three-dimensional constructs that resemble the architectural features, components, and mechanical properties of in vivo tissue. This technique features a newly developed sacrificial material, BSA rubber, which transfers detailed spatial features, reproducing the in vivo architectures of a wide variety of tissues.

Dreidimensionale Biomimetic Technologie: Neuartige Biorubber Erzeugt definierte Mikro- und Makro-Skala Architekturen in Collagen Hydrogele

Tissue scaffolds play a crucial role in the tissue regeneration process. The ideal scaffold must fulfill several requirements such as having proper ...

Multimodal 3D Printing of Phantoms to Simulate Biological Tissue

Biomedical optical imaging is playing an important role in diagnosis and treatment of various diseases. However, the accuracy and the reproducibility of an optical imaging device are greatly affected by the performance characteristics of its components, the test environment, and the operations. Therefore, it is necessary to calibrate these devices by traceable phantom standards. However, most of the currently available phantoms are homogeneous phantoms that cannot simulate multimodal and dynamic characteristics of biological tissue. Here, we show the fabrication of heterogeneous tissue-simulating phantoms using a production line integrating a spin coating module, a polyjet module, a fused deposition modeling (FDM) module, and an automatic control framework. The structural information and the optical parameters of a &#34;digital optical phantom&#34; are defined in a prototype file, imported to the production line, and fabricated layer-by-layer with sequential switch between different printing modalities. Technical capability of such a production line is exemplified by the automatic printing of skin-simulating phantoms that comprise the epidermis, dermis, subcutaneous tissue, and an embedded tumor.

Spin coating, polyjet printing, and fused deposition modeling are integrated to produce multilayered heterogeneous phantoms that simulate structural and functional properties of biological tissue.

Multimodaler 3D-Druck von Phantomen zur Simulation von biologischem Gewebe

Biomedical optical imaging is playing an important role in diagnosis and treatment of various diseases. However, the accuracy and the reproducibility of ...

Interactive Molecular Model Assembly with 3D Printing

With the growth in accessibility of 3D printing, there has been a growing application of and interest in additive manufacturing processes in chemical laboratories and chemical education. Building on the long and successful history of physical modeling of molecular systems, we present select models along with a protocol to facilitate 3D printing of molecular structures that are able to do more than represent shape and connectivity. Models assembled as described incorporate dynamic aspects and degrees of freedom into saturated hydrocarbon structures. As a representative example, cyclohexane was assembled from parts printed and finished using different thermoplastics, and the resulting models retain their functionality at a variety of scales. The resulting structures show configurational space accessibility consistent with calculations and literature, and versions of these structures can be used as aids to illustrate concepts that are difficult to convey in other ways. This exercise enables us to evaluate successful printing protocols, make practical recommendations for assembly, and outline design principles for physical modeling of molecular systems. The provided structures, procedures, and results provide a foundation for individual manufacture and exploration of molecular structure and dynamics with 3D printing.

Physical modeling of microscopic systems helps obtain insights that are difficult to gain by other means. To facilitate the construction of physical molecular models, we demonstrate how 3D printing can be used to assemble functional macroscopic models that capture qualities of molecular systems in a tactile way.

Interaktive molekulare Modellbaugruppe mit 3D-Druck

With the growth in accessibility of 3D printing, there has been a growing application of and interest in additive manufacturing processes in chemical ...

Chemie

Design and Development of a Three-Dimensionally Printed Microscope Mask Alignment Adapter for the Fabrication of Multilayer Microfluidic Devices

This project aims to develop an easy-to-use and cost-effective platform for the fabrication of precise, multilayer microfluidic devices, which typically can only be achieved using costly equipment in a clean room setting. The key part of the platform is a three dimensionally (3D) printed microscope mask alignment adapter (MMAA) compatible with regular optical microscopes and ultraviolet (UV) light exposure systems. The overall process of creating the device has been vastly simplified because of the work done to optimize the device design. The process entails finding the proper dimensions for the equipment available in the laboratory and 3D-printing the MMAA with the optimized specifications. Experimental results show that the optimized MMAA designed and manufactured by 3D printing performs well with a common microscope and light exposure system. Using a master mold prepared by the 3D-printed MMAA, the resulting microfluidic devices with multilayered structures contain alignment errors of &lt;10 &#181;m, which is sufficient for common microchips. Although human error through transportation of the device to the UV light exposure system can cause larger fabrication errors, the minimal errors achieved in this study are attainable with practice and care. Furthermore, the MMAA can be customized to fit any microscope and UV exposure system by making changes to the modeling file in the 3D printing system. This project provides smaller laboratories with a useful research tool as it only requires the use of equipment that is typically already available to laboratories that produce and use microfluidic devices. The following detailed protocol outlines the design and 3D printing process for the MMAA. In addition, the steps for procuring a multilayer master mold using the MMAA and producing poly(dimethylsiloxane) (PDMS) microfluidic chips is also described herein.

This project allows small laboratories to develop an easy-to-use platform for the fabrication of precise multilayer microfluidic devices. The platform consists of a three-dimensionally printed microscope mask alignment adapter using which multilayer microfluidic devices with alignment errors of &lt;10 &#181;m were achieved.

Design und Entwicklung eines dreidimensional gedruckten Mikroskopmasken-Alignment-Adapters für die Herstellung von mehrschichtigen mikrofluidischen Geräten

This project aims to develop an easy-to-use and cost-effective platform for the fabrication of precise, multilayer microfluidic devices, which typically ...

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties dependent on the chemical composition of the resin. In the current work, 3D printed materials are post-functionalized using the 3D printer hardware via a secondary surface-initiated polymerization process, thus providing independent control over the bulk and interfacial material properties. This process begins with preparing liquid resins, which contain a monofunctional monomer, a crosslinking multifunctional monomer, a photochemically labile species that enables initiation of polymerization, and critically, a thiocarbonylthio compound which facilitates reversible addition-fragmentation chain transfer (RAFT) polymerization. The thiocarbonylthio compound, known commonly as a RAFT agent, mediates the chain growth polymerization process and provides polymeric materials with more homogeneous network structures. The liquid resin is cured in a layer-by-layer fashion using a commercially available digital light processing 3D printer to give three-dimensional materials having spatially controlled geometries. The initial resin is removed and replaced with a new mixture containing functional monomers and photoinitiating species. The 3D printed material is then exposed to light from the 3D printer in the presence of the new functional monomer mixture. This allows photoinduced surface-initiated polymerization to occur from the latent RAFT agent groups on the surface of the 3D printed material. Given the chemical flexibility of both resins, this process allows a wide range of 3D printed materials to be produced with tailorable bulk and interfacial properties.

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

The present protocol describes the digital light processing-based 3D printing of polymeric materials using type I photoinitiated reversible addition-fragmentation chain transfer polymerization and the subsequent in situ material post-functionalization via surface-mediated polymerization. Photoinduced 3D printing provides materials with independently tailored and spatially controlled bulk and interfacial properties.

3D-Druck und In-situ-Oberflächenmodifikation mittels photoinitiierter reversibler Additions-Fragmentierungskettentransfer-Polymerisation Typ I

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties ...

Novel Process for 3D Printing Decellularized Matrices

3D bioprinting aims to create custom scaffolds that are biologically active and accommodate the desired size and geometry. A thermoplastic backbone can provide mechanical stability similar to native tissue while biologic agents offer compositional cues to progenitor cells, leading to their migration, proliferation, and differentiation to reconstitute the original tissues/organs1,2. Unfortunately, many 3D printing compatible, bioresorbable polymers (such as polylactic acid, PLA) are printed at temperatures of 210 &#176;C or higher - temperatures that are detrimental to biologics. On the other hand, polycaprolactone (PCL), a different type of polyester, is a bioresorbable, 3D printable material that has a gentler printing temperature of 65 &#176;C. Therefore, it was hypothesized that decellularized extracellular matrix (DM) contained within a thermally protective PLA barrier could be printed within PCL filament and remain in its functional conformation. In this work, osteochondral repair was the application for which the hypothesis was tested. As such, porcine cartilage was decellularized and encapsulated in polylactic acid (PLA) microspheres which were then extruded with polycaprolactone (PCL) into filament to produce 3D constructs via fused deposition modeling. The constructs with or without the microspheres (PLA-DM/PCL and PCL(-), respectively) were evaluated for differences in surface features.

This protocol describes the production of polycaprolactone (PCL) filament with embedded polylactic acid (PLA) microspheres which contain decellularized matrices (DM) for 3D printing of structural tissue engineering constructs.

Neuartiges Verfahren für den 3D-Druck Decellularized Matrizen

3D bioprinting aims to create custom scaffolds that are biologically active and accommodate the desired size and geometry. A thermoplastic backbone can ...

Photoabstimmbare biogedruckte Hydrogele zur Untersuchung zellulärer Reaktionen auf ECM-Versteifung

3D Bioprinting Phototunable Hydrogels to Study Fibroblast Activation

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

Autor im Rampenlicht: Chronische Lungenerkrankungen mit 3D-gedruckten phototunablen Hydrogelen verstehen 

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

3D-Bioprinting von phototunbaren Hydrogelen zur Untersuchung der Fibroblastenaktivierung

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