Die Autoren erkennen Finanzierung von NIH R00 HL115123 und Brown University School of Engineering. Sie sind auch dankbar für die Braun-Design-Workshop und Chris Bull für die Ausbildung und Unterstützung bei der Laser-Cutter.

<ol><li>Qin, D., Xia, Y., Whitesides, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Soft+lithography+for+micro-+and+nanoscale+patterning%5BTitle%5D)+AND+%22Nat.+Protoc%22%5BJournal%5D)">Soft lithography for micro- and nanoscale patterning.</a> Nat. Protoc. 5, 491(2010).</li>
<li>Rogers, J. A., Nuzzo, R. G. <a target="_blank" href="https://www-sciencedirect-com.bdigitaluss.remotexs.co/science/article/pii/S1369702105007029">Recent progress in soft lithography.</a> Mater. Today. 8, 50-56 (2005).</li>
<li>Whitesides, G. M., Ostuni, E., Takayama, S., Jiang, X., Ingber, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Soft+Lithography+in+Biology+and+Biochemistry%5BTitle%5D)+AND+%22Annu.+Rev.+Biomed.+Eng%22%5BJournal%5D)">Soft Lithography in Biology and Biochemistry.</a> Annu. Rev. Biomed. Eng. 3, 335-373 (2001).</li>
<li>Isiksacan, Z., Guler, M. T., Aydogdu, B., Bilican, I., Elbuken, C. <a target="_blank" href="http://iopscience.iop.org/article/10.1088/0960-1317/26/3/035008">Rapid fabrication of microfluidic PDMS devices from reusable PDMS molds using laser ablation.</a> J. Micromechanics Microengineering. 26, 035008(2016).</li>
<li>Lee, K. Y., Mooney, D. J. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/11710233">Hydrogels for Tissue Engineering.</a> Chem. Rev. 101, 1869-1880 (2001).</li>
<li>Kloxin, A., Kloxin, C., Bowman, C., Anseth, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mechanical+properties+of+cellularly+responsive+hydrogels+and+their+experimental+determination%5BTitle%5D)+AND+%22Adv.+Mater.+Deerfield+Beach+Fla%22%5BJournal%5D)">Mechanical properties of cellularly responsive hydrogels and their experimental determination.</a> Adv. Mater. Deerfield Beach Fla. 22, 3484-3494 (2010).</li>
<li>Aubin, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Directed+3D+cell+alignment+and+elongation+in+microengineered+hydrogels%5BTitle%5D)+AND+%22Biomaterials%22%5BJournal%5D)">Directed 3D cell alignment and elongation in microengineered hydrogels.</a> Biomaterials. 31, 6941-6951 (2010).</li>
<li>Jaiswal, M. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Vacancy-Driven+Gelation+Using+Defect-Rich+Nanoassemblies+of+2D+Transition+Metal+Dichalcogenides+and+Polymeric+Binder+for+Biomedical+Applications%5BTitle%5D)+AND+%22Adv.+Mater%22%5BJournal%5D)">Vacancy-Driven Gelation Using Defect-Rich Nanoassemblies of 2D Transition Metal Dichalcogenides and Polymeric Binder for Biomedical Applications.</a> Adv. Mater. 29, (2017).</li>
<li>Lian, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Directed+cardiomyocyte+differentiation+from+human+pluripotent+stem+cells+by+modulating+Wnt%2F%CE%B2-catenin+signaling+under+fully+defined+conditions%5BTitle%5D)+AND+%22Nat.+Protoc%22%5BJournal%5D)">Directed cardiomyocyte differentiation from human pluripotent stem cells by modulating Wnt/β-catenin signaling under fully defined conditions.</a> Nat. Protoc. 8, 162-175 (2013).</li>
<li>Boxshall, K., et al. <a target="_blank" href="http://onlinelibrary.wiley.com/doi/10.1002/sia.2274/abstract">Simple surface treatments to modify protein adsorption and cell attachment properties within a poly(dimethylsiloxane) micro-bioreactor.</a> Surf. Interface Anal. 38, 198-201 (2006).</li>
<li>Pins, G. D., Christiansen, D. L., Patel, R., Silver, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Self-assembly+of+collagen+fibers.+Influence+of+fibrillar+alignment+and+decorin+on+mechanical+properties%5BTitle%5D)+AND+%22Biophys.+J%22%5BJournal%5D)">Self-assembly of collagen fibers. Influence of fibrillar alignment and decorin on mechanical properties.</a> Biophys. J. 73, 2164-2172 (1997).</li>
<li>Pipan, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effects+of+antifibrinolytic+agents+on+the+life+span+of+fibrin+sealant%5BTitle%5D)+AND+%22J.+Surg.+Res%22%5BJournal%5D)">Effects of antifibrinolytic agents on the life span of fibrin sealant.</a> J. Surg. Res. 53, 402-407 (1992).</li>
<li>Roberts, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Stromal+Cells+in+Dense+Collagen+Promote+Cardiomyocyte+and+Microvascular+Patterning+in+Engineered+Human+Heart+Tissue%5BTitle%5D)+AND+%22Tissue+Eng.+Part+A%22%5BJournal%5D)">Stromal Cells in Dense Collagen Promote Cardiomyocyte and Microvascular Patterning in Engineered Human Heart Tissue.</a> Tissue Eng. Part A. 22, 633-644 (2016).</li>
<li>Ye, K. Y., Sullivan, K. E., Black, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Encapsulation+of+Cardiomyocytes+in+a+Fibrin+Hydrogel+for+Cardiac+Tissue+Engineering%5BTitle%5D)+AND+%22JoVE%22%5BJournal%5D)">Encapsulation of Cardiomyocytes in a Fibrin Hydrogel for Cardiac Tissue Engineering.</a> JoVE. , (2011).</li>
<li>Zimmermann, W. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Tissue+Engineering+of+a+Differentiated+Cardiac+Muscle+Construct%5BTitle%5D)+AND+%22Circ.+Res%22%5BJournal%5D)">Tissue Engineering of a Differentiated Cardiac Muscle Construct.</a> Circ. Res. 90, 223-230 (2002).</li>
<li>McCain, M. L., Agarwal, A., Nesmith, H. W., Nesmith, A. P., Parker, K. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Micromolded+Gelatin+Hydrogels+for+Extended+Culture+of+Engineered+Cardiac+Tissues%5BTitle%5D)+AND+%22Biomaterials%22%5BJournal%5D)">Micromolded Gelatin Hydrogels for Extended Culture of Engineered Cardiac Tissues.</a> Biomaterials. 35, 5462-5471 (2014).</li>
<li>Hu, J. J., Chen, G. W., Liu, Y. C., Hsu, S. S. <a target="_blank" href="https://link-springer-com.bdigitaluss.remotexs.co/article/10.1007/s11340-013-9826-2">Influence of Specimen Geometry on the Estimation of the Planar Biaxial Mechanical Properties of Cruciform Specimens.</a> Exp. Mech. 54, 615-631 (2014).</li>
<li>Munarin, F., Kaiser, N. J., Kim, T. Y., Choi, B. R., Coulombe, K. L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Laser-Etched+Designs+for+Molding+Hydrogel-Based+Engineered+Tissues%5BTitle%5D)+AND+%22Tissue+Eng.+Part+C+Methods%22%5BJournal%5D)">Laser-Etched Designs for Molding Hydrogel-Based Engineered Tissues.</a> Tissue Eng. Part C Methods. 23, 311-321 (2017).</li>
<li>Zhang, H., Chiao, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Anti-fouling+Coatings+of+Poly%28dimethylsiloxane%29+Devices+for+Biological+and+Biomedical+Applications%5BTitle%5D)+AND+%22J.+Med.+Biol.+Eng%22%5BJournal%5D)">Anti-fouling Coatings of Poly(dimethylsiloxane) Devices for Biological and Biomedical Applications.</a> J. Med. Biol. Eng. 35, 143-155 (2015).</li>
</ol>

Die Autoren haben nichts preisgeben.

Maßgeschneiderte PDMS-Schimmel-Geometrien, die kompatibel mit Gewebekultur sind haben großen Nutzen in der Abstimmung wichtige technische Gewebeeigenschaften, z. B. Ausrichtung der Zellen, Diffusionsgeschwindigkeit und effektive Steifigkeit. Darüber hinaus sind diese Formen sehr nützlich für die Zubereitung von Geweben für Analyse-Anwendungen in denen Geometrie, wie mechanische Tests16,17ankommt. Vorbereitung dieser Geräte vom Laser geschnitten negative Me...

In den letzten zwei Jahrzehnten wurde weiche Lithographie ausgiebig als Herstellung Technik verwendet, um wissenschaftliche Forschung, insbesondere in den Bereichen der Mikrofluidik, Materialforschung und Tissue engineering1,2zu unterstützen, 3. Replik-Formteil, in dem ein Objekt mit einer gewünschten Form aus einer Negativform master erstellt wird bietet eine bequeme und kostengünstige Verfahren zur Herstellung von positive PDMS repliziert, die für den Guss geformte Hydrogele verwendet werden kann. Jedoch die erforderliche negative Meister-Schimmel entstehen in der Regel mit Microfabrication Techniken, die sind in der Größe, begrenzt, teuer, zeitaufwendig, und benötigen sauberes Zimmer Platz und hoch entwickelte Ausrüstung. 3D-Druck bietet eine mögliche Alternative, zwar seine Nützlichkeit ist etwas eingeschränkt, aufgrund der begrenzten Auflösung günstigere Drucker und die chemischen Wechselwirkungen zwischen gemeinsamen 3D-Drucker Polymere und PDMS, die Aushärtung hemmen können.
Laser Cutter Systeme in der Lage sowohl schneiden und Ätzen Materialien wie Kunststoff, Holz, Glas und Metall sind vor kurzem drastisch weniger teuer und daher leichter zugänglich für die Herstellung von Recherche-Tools geworden. Handelsgüte Laserschneidanlagen sind in der Lage, die Herstellung von Objekten auf der Zentimeter-Skala mit minimalen Funktionen kleiner als 25 µm und weitere erfordern minimale Ausbildung, Fachwissen und Zeit zu verwenden. Während Laser-Ablation von PDMS in der Herstellung der Mikrofluidik Geräte verwendet wurde, hat nach unserer Kenntnis keine Handschrift ein Prozesses beschrieben durch welche Millimeter und Zentimeter Skala Formen aus lasergeschnittenen negative Meister-Schimmel4 gefertigt werden können .
Wir haben diese Technik verwendet, in erster Linie auf um die Form der technischen Gewebe zu manipulieren, um Nährstoff Diffusion, zelluläre Ausrichtung und mechanischen Eigenschaften5,6,7zu verbessern. Allerdings ermöglicht die Vielseitigkeit dieser Technik für den Einsatz in allen Bereichen wo geformte Hydrogele von Interesse, wie Drogen Lieferung und Material Science Forschung8 sind. Mit Zugriff auf ein Laser-Cutter, PDMS Schimmel Wiederholungen gemacht werden können für nahezu jede Geometrie ohne Überhänge (die Entfernung ohne eine mehrteilige Form, die außerhalb des Rahmens dieses Manuskriptes ist hemmen würde) und das passt in den Dimensionen des Laser-Bettes.

<table><tbody><tr><td>&lt;strong&gt;Item&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Bovine fibrinogen</td><td>Sigma</td><td>F8630-5G</td><td>Constructs</td></tr><tr><td>Bovine thrombin</td><td>Sigma</td><td>T6634-250UN</td><td>Constructs</td></tr><tr><td>Bovine aprotinin</td><td>Sigma</td><td>10820-25MG</td><td>Constructs</td></tr><tr><td>Rat tail collagen I, 4 mg/mL</td><td>Advanced Biomatrix</td><td>5153-100MG</td><td>Constructs</td></tr><tr><td>Sodim chloride</td><td>Fisher</td><td>BP358-10</td><td>Constructs</td></tr><tr><td>PBS</td><td>Life Technologies</td><td>14190-250</td><td>Constructs</td></tr><tr><td>Fine forceps</td><td>Fine Science Tools</td><td>11252-20</td><td>Constructs</td></tr><tr><td>Sylgard 184 silicone elastomer</td><td>Corning</td><td>4019862</td><td>PDMS Molds</td></tr><tr><td>Lab tape</td><td>Fisher</td><td>15-901-5R</td><td>PDMS Molds</td></tr><tr><td>Acrylic, 1/4&quot; thick</td><td>McMaster-Carr</td><td>8560K356</td><td>PDMS Molds</td></tr><tr><td>HEPES Buffer, 1 M</td><td>Sigma</td><td>H3537-100ML</td><td>Constructs</td></tr><tr><td>RPMI 1640 medium, powder</td><td>Fisher</td><td>31800-089</td><td>Constructs</td></tr><tr><td>Calcium chloride dihydrate</td><td>Fisher</td><td>AC423520250</td><td>Constructs</td></tr><tr><td>Magnesium chloride hexahydrate</td><td>Fisher</td><td>M33 500</td><td>Constructs</td></tr><tr><td>Potassium chloride</td><td>Sigma</td><td>P9541-500G</td><td>Constructs</td></tr><tr><td>Sodium phosphate dibasic heptahydrate</td><td>Sigma</td><td>S9390-500G</td><td>Constructs</td></tr><tr><td>Glucose</td><td>Sigma</td><td>G5767-25G</td><td>Constructs</td></tr><tr><td>OCT</td><td>VWR</td><td>25608-930</td><td>Histology</td></tr><tr><td>Frozen block molds</td><td>VWR</td><td>25608-916</td><td>Histology</td></tr><tr><td>Hematoxylin</td><td>Fisher</td><td>3530 1</td><td>Histology</td></tr><tr><td>Eosin Y</td><td>Fisher</td><td>AC152880250</td><td>Histology</td></tr><tr><td>Fast green FCF</td><td>Fisher</td><td>AC410530250</td><td>Histology</td></tr><tr><td>&lt;strong&gt;Software&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Illustrator</td><td>Adobe Systems</td><td></td><td>Vector Graphics</td></tr><tr><td>Inkscape</td><td>(Open Source)</td><td></td><td>Vector Graphics</td></tr><tr><td>UCP (Universal Control Panel)</td><td>Universal Laser Systems</td><td></td><td>Laser Cutter Interface</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>PLS6.75 Laser Cutter</td><td>Universal Laser Systems</td><td></td><td>Laser Cutter</td></tr><tr><td>Micromechanical Analyzer</td><td>Aurora Scientific</td><td>1530A with 5 mN load cell</td><td>Mechanical Analysis</td></tr></tbody></table>

custom engineered tissue culture molds from laser-etched masters

Wie das Gebiet des Tissue Engineering weiterhin Reifen hat, gab es verstärktes Interesse an eine Vielzahl von Parametern, Gewebe, einschließlich Gewebe Form. Gewebe-Shape auf das Mikrometer Zentimeter maßstabsgetreu zu manipulieren kann direkte Ausrichtung der Zellen, effektive mechanische Eigenschaften zu ändern, und Beschränkungen in Bezug auf Nährstoff Verbreitung. Darüber hinaus kann das Gefäß, in dem ein Papiertaschentuch bereit ist, vermitteln mechanische Einschränkungen auf das Gewebe, wodurch Spannungsfelder, die weiter die Zelle und die Matrix-Struktur beeinflussen können. Geformtes Gewebe mit hoch reproduzierbare Abmessungen haben auch Dienstprogramm für in-vitro- Assays in welche, die Probe Maße kritisch, wie ganze Gewebe mechanische Analyse sind.
Dieses Manuskript beschreibt eine alternative Herstellungsverfahren unter Verwendung negative Meister-Schimmel aus Acryl Laser geätzten vorbereitet: diese Formen gut mit Polydimethylsiloxan (PDMS) durchführen, ermöglichen Designs mit den Maßen auf den Zentimeter Umfang und Funktion Größen kleiner als 25 µm und kann sein schnell konstruiert und gefertigt zu einem niedrigen Preis und mit minimaler Kompetenz. Die minimale Zeit und Kosten Anforderungen ermöglichen Laser geätzten Formen schnell auf wiederholt werden, bis ein optimales Design feststeht und einfach jedem Assay von Interesse, einschließlich derjenigen über den Bereich des Tissue Engineerings angepasst werden.

Die Optik der Laser-Cutter erzeugen geätzte Bereiche Abmessungen wie Ätzen Tiefe steigt geringfügig zurückgegangen, und Ergebnisse im Formenbau Wände mit einer sehr feinen Fase wegen zur Verjüngung des Laserstrahls. Dies wird dazu beitragen, das Entfernen der Besetzung PDMS Formen zu erleichtern, aber sollte sorgfältig geprüft werden, wenn negative Meister-Schimmel sehr tief geätzt (> 6 mm) sind erforderlich (Abbildung 1).
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Watch this Scientific Journal Video about Custom Engineered Tissue Culture Molds from Laser-etched Masters at JoVE.com

Custom Engineered Tissue Culture Molds from Laser-etched Masters

Hier präsentieren wir Ihnen eine schnelle, einfache und kostengünstige Methode zur Herstellung von benutzerdefinierten Polydimethylsiloxan-Formen, die für die Herstellung von Hydrogel-basierte Technische Gewebe mit komplexen Geometrien verwendet werden können. Wir beschreiben außerdem Ergebnisse aus mechanischen und histologischen Bewertungen auf veränderter kardialen Gewebe hergestellt, mit dieser Technik durchgeführt.

Custom-Engineered Tissue Culture Formen von gelasert meistern

As the field of tissue engineering has continued to mature, there has been increased interest in a wide range of tissue parameters, including tissue ...

custom-engineered-tissue-culture-molds-from-laser-etched-masters

Research

JoVE Journal

Bioengineering

6.4K Aufrufe.  Brown University. Hier präsentieren wir Ihnen eine schnelle, einfache und kostengünstige Methode zur Herstellung von benutzerdefinierten Polydimethylsiloxan-Formen, die für die Herstellung von Hydrogel-basierte Technische Gewebe mit komplexen Geometrien verwendet werden können. Wir beschreiben außerdem Ergebnisse aus mechanischen und histologischen Bewertungen auf veränderter kardialen Gewebe hergestellt, mit dieser Technik durchgeführt.

Serie: Custom Engineered Tissue Culture Molds from Laser-etched Masters

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.

Mikrofabrizierten Plattformen für Mechanisch Dynamische Cell Culture

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

Forschung

Biotechnik

Directed Cellular Self-Assembly to Fabricate Cell-Derived Tissue Rings for Biomechanical Analysis and Tissue Engineering

Each year, hundreds of thousands of patients undergo coronary artery bypass surgery in the United States.1 Approximately one third of these patients do not have suitable autologous donor vessels due to disease progression or previous harvest. The aim of vascular tissue engineering is to develop a suitable alternative source for these bypass grafts. In addition, engineered vascular tissue may prove valuable as living vascular models to study cardiovascular diseases. Several promising approaches to engineering blood vessels have been explored, with many recent studies focusing on development and analysis of cell-based methods.2-5 Herein, we present a method to rapidly self-assemble cells into 3D tissue rings that can be used in vitro to model vascular tissues.
To do this, suspensions of smooth muscle cells are seeded into round-bottomed annular agarose wells. The non-adhesive properties of the agarose allow the cells to settle, aggregate and contract around a post at the center of the well to form a cohesive tissue ring.6,7 These rings can be cultured for several days prior to harvesting for mechanical, physiological, biochemical, or histological analysis. We have shown that these cell-derived tissue rings yield at 100-500 kPa ultimate tensile strength8 which exceeds the value reported for other tissue engineered vascular constructs cultured for similar durations (&lt;30 kPa).9,10 Our results demonstrate that robust cell-derived vascular tissue ring generation can be achieved within a short time period, and offers the opportunity for direct and quantitative assessment of the contributions of cells and cell-derived matrix (CDM) to vascular tissue structure and function.

This article outlines a versatile method to create cell-derived tissue rings by cellular self-assembly. Smooth muscle cells seeded into ring-shaped agarose wells aggregate and contract to form robust three-dimensional (3D) tissues within 7 days. Millimeter-scale tissue rings are conducive to mechanical testing and serve as building blocks for tissue assembly.

Directed Cellular Self-Assembly to Cell-Derived Tissue Ringe für biomechanische Analyse und Tissue Engineering Fabricate

Each year, hundreds of thousands of patients undergo coronary artery bypass surgery in the United States.1 Approximately one third of these patients do ...

Evaluation of Cancer Stem Cell Migration Using Compartmentalizing Microfluidic Devices and Live Cell Imaging

In the last 40 years, the United States invested over 200 billion dollars on cancer research, resulting in only a 5% decrease in death rate. A major obstacle for improving patient outcomes is the poor understanding of mechanisms underlying cellular migration associated with aggressive cancer cell invasion, metastasis and therapeutic resistance1. Glioblastoma Multiforme (GBM), the most prevalent primary malignant adult brain tumor2, exemplifies this difficulty. Despite standard surgery, radiation and chemotherapies, patient median survival is only fifteen months, due to aggressive GBM infiltration into adjacent brain and rapid cancer recurrence2. The interactions of aberrant cell migratory mechanisms and the tumor microenvironment likely differentiate cancer from normal cells3. Therefore, improving therapeutic approaches for GBM require a better understanding of cancer cell migration mechanisms. Recent work suggests that a small subpopulation of cells within GBM, the brain tumor stem cell (BTSC), may be responsible for therapeutic resistance and recurrence. Mechanisms underlying BTSC migratory capacity are only starting to be characterized1,4.
Due to a limitation in visual inspection and geometrical manipulation, conventional migration assays5 are restricted to quantifying overall cell populations. In contrast, microfluidic devices permit single cell analysis because of compatibility with modern microscopy and control over micro-environment6-9.
We present a method for detailed characterization of BTSC migration using compartmentalizing microfluidic devices. These PDMS-made devices cast the tissue culture environment into three connected compartments: seeding chamber, receiving chamber and bridging microchannels. We tailored the device such that both chambers hold sufficient media to support viable BTSC for 4-5 days without media exchange. Highly mobile BTSCs initially introduced into the seeding chamber are isolated after migration though bridging microchannels to the parallel receiving chamber. This migration simulates cancer cellular spread through the interstitial spaces of the brain. The phase live images of cell morphology during migration are recorded over several days. Highly migratory BTSC can therefore be isolated, recultured, and analyzed further. 
Compartmentalizing microfluidics can be a versatile platform to study the migratory behavior of BTSCs and other cancer stem cells. By combining gradient generators, fluid handling, micro-electrodes and other microfluidic modules, these devices can also be used for drug screening and disease diagnosis6. Isolation of an aggressive subpopulation of migratory cells will enable studies of underlying molecular mechanisms.

A compartmentalizing microfluidic device for investigating cancer stem cell migration is described. This novel platform creates a viable cellular microenvironment and enables microscopic visualization of live cell locomotion. Highly motile cancer cells are isolated to study molecular mechanisms of aggressive infiltration, potentially leading to more effective future therapies.

Evaluation of Cancer Stem Cell Migration Mit Abschottung Mikrofluidiksysteme und Live Cell Imaging

In the last 40 years, the United States invested over 200 billion dollars on cancer research, resulting in only a 5% decrease in death rate. A major ...

Medizin

Density Gradient Multilayered Polymerization (DGMP): A Novel Technique for Creating Multi-compartment, Customizable Scaffolds for Tissue Engineering

Complex tissue culture matrices, in which types and concentrations of biological stimuli (e.g. growth factors, inhibitors, or small molecules) or matrix structure (e.g. composition, concentration, or stiffness of the matrix) vary over space, would enable a wide range of investigations concerning how these variables affect cell differentiation, migration, and other phenomena. The major challenge in creating layered matrices is maintaining the structural integrity of layer interfaces without diffusion of individual components from each layer1. Current methodologies to achieve this include photopatterning2-3, lithography4, sequential functionalization5, freeze drying6, microfluidics7, or centrifugation8, many of which require sophisticated instrumentation and technical skills. Others rely on sequential attachment of individual layers, which may lead to delamination of layers9. 
DGMP overcomes these issues by using an inert density modifier such as iodixanol to create layers of varying densities10. Since the density modifier can be mixed with any prepolymer or bioactive molecule, DGMP allows each scaffold layer to be customized. Simply varying the concentration of the density modifier prevents mixing of adjacent layers while they remain aqueous. Subsequent single step polymerization gives rise to a structurally continuous multilayered scaffold, in which each layer has distinct chemical and mechanical properties. The density modifier can be easily removed with sufficient rinsing without perturbation of the individual layers or their components. This technique is therefore well suited for creating hydrogels of various sizes, shapes, and materials.
A protocol for fabricating a 2D-polyethylene glycol (PEG) gel, in which alternating layers incorporate RGDS-350, is outlined below. We use PEG because it is biocompatible and inert. RGDS, a cell adhesion peptide11, is used to demonstrate spatial restriction of a biological cue, and the conjugation of a fluorophore (Alexa Fluor 350) enables us to visually distinguish various layers. This procedure can be adapted for other materials (e.g. collagen, hyaluronan, etc.) and can be extended to fabricate 3D gels with some modifications10.

Density Gradient Multilayered Polymerization DGMP: A Novel Technique for Creating Multi-compartment, Customizable Scaffolds for Tissue Engineering

Here we describe a unique strategy for creating biocompatible, layered matrices with continuous interfaces between distinct layers for tissue engineering. Such a scaffold could provide an ideal customizable environment to modulate cell behavior by various biological, chemical or mechanical cues

Density Gradient Multilayered Polymerisation (DGMP): A Novel Technique für das Erstellen von Multi-Fach, Anpassbare Scaffolds für das Tissue Engineering

Complex tissue culture matrices, in which types and concentrations of biological stimuli (e.g. growth factors, inhibitors, or small molecules) or matrix ...

Microfabrication of Chip-sized Scaffolds for Three-dimensional Cell cultivation

Using microfabrication technologies is a prerequisite to create scaffolds of reproducible geometry and constant quality for three-dimensional cell cultivation. These technologies offer a wide spectrum of advantages not only for manufacturing but also for different applications. The size and shape of formed cell clusters can be influenced by the exact and reproducible architecture of the microfabricated scaffold and, therefore, the diffusion path length of nutrients and gases can be controlled.1 This is unquestionably a useful tool to prevent apoptosis and necrosis of cells due to an insufficient nutrient and gas supply or removal of cellular metabolites.
Our polymer chip, called CellChip, has the outer dimensions of 2 x 2 cm with a central microstructured area. This area is subdivided into an array of up to 1156 microcontainers with a typical dimension of 300 m edge length for the cubic design (cp- or cf-chip) or of 300 m diameter and depth for the round design (r-chip).2
So far, hot embossing or micro injection moulding (in combination with subsequent laborious machining of the parts) was used for the fabrication of the microstructured chips. Basically, micro injection moulding is one of the only polymer based replication techniques that, up to now, is capable for mass production of polymer microstructures.3 However, both techniques have certain unwanted limitations due to the processing of a viscous polymer melt with the generation of very thin walls or integrated through holes. In case of the CellChip, thin bottom layers are necessary to perforate the polymer and provide small pores of defined size to supply cells with culture medium e.g. by microfluidic perfusion of the containers.
In order to overcome these limitations and to reduce the manufacturing costs we have developed a new microtechnical approach on the basis of a down-scaled thermoforming process. For the manufacturing of highly porous and thin walled polymer chips, we use a combination of heavy ion irradiation, microthermoforming and track etching. In this so called "SMART" process (Substrate Modification And Replication by Thermoforming) thin polymer films are irradiated with energetic heavy projectiles of several hundred MeV introducing so-called "latent tracks" Subsequently, the film in a rubber elastic state is formed into three dimensional parts without modifying or annealing the tracks. After the forming process, selective chemical etching finally converts the tracks into cylindrical pores of adjustable diameter.

We present two processes for the microfabrication of porous polymer chips for three-dimensional cell cultivation. The first one is hot embossing combined with a solvent vapour welding process. The second one uses a recently developed microthermoforming process combined with ion track technology leading to a significant simplification of manufacture.

Microfabrication der Chip-Größe Gerüste für die dreidimensionale Kultivierung der Zellen

Using microfabrication technologies is a prerequisite to create scaffolds of reproducible geometry and constant quality for three-dimensional cell ...

Biologie

A Multi-compartment CNS Neuron-glia Co-culture Microfluidic Platform

We present a novel multi-compartment neuron co-culture microsystem platform for in vitro CNS axon-glia interaction research, capable of conducting up to six independent experiments in parallel for higher-throughput. We developed a new fabrication method to create microfluidic devices having both micro and macro scale structures within the same device through a single soft-lithography process, enabling mass fabrication with good repeatability.
The multi-compartment microfluidic co-culture platform is composed of one soma compartment for neurons and six axon/glia compartments for oligodendrocytes (OLs). The soma compartment and axon/glia compartments are connected by arrays of axon-guiding microchannels that function as physical barriers to confine neuronal soma in the soma compartment, while allowing axons to grow into axon/glia compartments. OLs loaded into axon/glia compartments can interact only with axons but not with neuronal soma or dendrites, enabling localized axon-glia interaction studies. The microchannels also enabled fluidic isolation between compartments, allowing six independent experiments to be conducted on a single device for higher throughput.
Soft-lithography using poly(dimethylsiloxane) (PDMS) is a commonly used technique in biomedical microdevices. Reservoirs on these devices are commonly defined by manual punching. Although simple, poor alignment and time consuming nature of the process makes this process not suitable when large numbers of reservoirs have to be repeatedly created. The newly developed method did not require manual punching of reservoirs, overcoming such limitations. First, seven reservoirs (depth: 3.5 mm) were made on a poly(methyl methacrylate) (PMMA) block using a micro-milling machine. Then, arrays of ridge microstructures, fabricated on a glass substrate, were hot-embossed against the PMMA block to define microchannels that connect the soma and axon/glia compartments. This process resulted in macro-scale reservoirs (3.5 mm) and micro-scale channels (2.5 &mu;m) to coincide within a single PMMA master. A PDMS replica that served as a mold master was obtained using soft-lithography and the final PDMS device was replicated from this master.
Primary neurons from E16-18 rats were loaded to the soma compartment and cultured for two weeks. After one week of cell culture, axons crossed microchannels and formed axonal only network layer inside axon/glia compartments. Axons grew uniformly throughout six axon/glia compartments and OLs from P1-2 rats were added to axon/glia compartments at 14 days in vitro for co-culture.

We developed a novel multi-compartment neuron co-culture microsystem platform for in vitro CNS axon-glia interaction research. The platform is capable of conducting up to six independent experiments in parallel and was fabricated using a newly developed macro/micro hybrid fabrication method.

Ein Multi-Kompartiment-ZNS-Neuron-Glia-Co-Kultur mikrofluidischen Plattform

We present a novel multi-compartment neuron co-culture microsystem platform for in vitro CNS axon-glia interaction research, capable of conducting up to ...

Fabrication of Custom Agarose Wells for Cell Seeding and Tissue Ring Self-assembly Using 3D-Printed Molds

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease modeling. Self-assembled tissues offer advantages over scaffold-based tissue engineering, such as enhanced matrix deposition, strength, and function. However, there are few available methods for fabricating 3D tissues without seeding cells on or within a supporting scaffold. Previously, we developed a system for fabricating self-assembled tissue rings by seeding cells into non-adhesive agarose wells. A polydimethylsiloxane (PDMS) negative was first cast in a machined polycarbonate mold, and then agarose was gelled in the PDMS negative to create ring-shaped cell seeding wells. However, the versatility of this approach was limited by the resolution of the tools available for machining the polycarbonate mold. Here, we demonstrate that 3D-printed plastic can be used as an alternative to machined polycarbonate for fabricating PDMS negatives. The 3D-printed mold and revised mold design is simpler to use, inexpensive to produce, and requires significantly less agarose and PDMS per cell seeding well. We have demonstrated that the resulting agarose wells can be used to create self-assembled tissue rings with customized diameters from a variety of different cell types. Rings can then be used for mechanical, functional, and histological analysis, or for fabricating larger and more complex tubular tissues.

This protocol describes a platform for fabricating self-assembled tissue rings in variable sizes using a customized 3D-printed plastic mold. PDMS negatives are cured in the 3D-printed mold; then agarose is cast in the cured PDMS negatives. Cells are seeded into the resulting agarose wells where they aggregate into tissue rings.

Herstellung von benutzerdefinierten Agarose Brunnen für die Aussaat von Zelle und Gewebe Ring Selbstmontage mit 3D-Druck Formen

Engineered tissues are being used clinically for tissue repair and replacement, and are being developed as tools for drug screening and human disease ...

Herstellung von Maussehnen-Assembloiden zur Untersuchung zellulärer Wechselwirkungen bei Krankheiten

Engineering Tendon Assembloids to Probe Cellular Crosstalk in Disease and Repair

Tendons enable locomotion by transferring muscle forces to bones. They rely on a tough tendon core comprising collagen fibers and stromal cell populations. This load-bearing core is encompassed, nourished, and repaired by a synovial-like tissue layer comprising the extrinsic tendon compartment. Despite this sophisticated design, tendon injuries are common, and clinical treatment still relies on physiotherapy and surgery. The limitations of available experimental model systems have slowed the development of novel disease-modifying treatments and relapse-preventing clinical regimes. 
In vivo human studies are limited to comparing healthy tendons to end-stage diseased or ruptured tissues sampled during repair surgery and do not allow the longitudinal study of the underlying tendon disease. In vivo animal models also present important limits regarding opaque physiological complexity, the ethical burden on the animals, and large economic costs associated with their use. Further, in vivo animal models are poorly suited to systematic probing of drugs and multicellular, multi-tissue interaction pathways. Simpler in vitro model systems have also fallen short. One major reason is a failure to adequately replicate the three-dimensional mechanical loading necessary to meaningfully study tendon cells and their function. 
The new 3D model system presented here alleviates some of these issues by exploiting murine tail tendon core explants. Importantly, these explants are easily accessible in large numbers from a single mouse, retain 3D in situ loading patterns at the cellular level, and feature an in vivo-like extracellular matrix. In this protocol, step-by-step instructions are given on how to augment tendon core explants with collagen hydrogels laden with muscle-derived endothelial cells, tendon-derived fibroblasts, and bone marrow-derived macrophages to substitute disease- and injury-activated cell populations within the extrinsic tendon compartment. It is demonstrated how the resulting tendon assembloids can be challenged mechanically or through defined microenvironmental stimuli to investigate emerging multicellular crosstalk during disease and injury.

Autor im Rampenlicht: Förderung der Sehnenforschung durch die Entwicklung von Maus-Assembloiden zum Verständnis zellulärer Mechanismen

Here, we present an assembloid model system to mimic tendon cellular crosstalk between the load-bearing tendon core tissue and an extrinsic compartment containing cell populations activated by disease and injury. As an important use case, we demonstrate how the system can be deployed to probe disease-relevant activation of extrinsic endothelial cells.

Custom-Engineered Tissue Culture Formen von gelasert meistern

Zusammenfassung

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