Um Margaret CM Smith für die freundliche Bereitstellung des Integrase-Klon Drittmittelförderung von: Genome Kanada / Genome Prairie NSERC Discovery and Strategic Project Zuschüsse

1. Die Produktion von Kultur <ol><li> Planen sterilen flüssigen Medien: TY 10 (5 g / l Trypton, 3 g / l Hefeextrakt, 0,44 g / l Calciumchlorid-Dihydrat), und LB 11 (10 g / l Trypton, 5 g / l Hefeextrakt, 5 g / Natriumchlorid, pH 7). </li><li> Impfen von einer einzigen Kolonie: SmUW227 (S. meliloti LP-Stamm: Bau wird an anderer Stelle beschrieben werden, Stamm Bau Details auf Anfrage) () in 5 ml TY-Medium mit 50 pg / ml Spectinomycin. Beimpfen die folgenden Stämme in 5 ml LB flüssige Medien, in Ergänzung mit dem Antibiotikum gegeben: E. coli DH5 12 mit pJC2, die Integrase-Expressionsplasmid, mit 10 ug / ml Tetracyclin, E. coli MT616 13, die Mobilizer, mit 10 ug / ml Chloramphenicol, und E. coli DH5 mit pJH110, der Spender Kassette Plasmid, mit 5 pg / ml Gentamicin. </li><li> Inkubieren E. coli-Stämme über Nacht bei 37 &amp;deg; C unter ständigem Schütteln. Inkubieren S. meliloti-Stamm bei 30 ° C für zwei Tage unter Schütteln. Es ist möglich, einen S. zu erhalten meliloti Kultur über Nacht mit einem größeren Inokulum (1:500 Subkultur einer gesättigten Kultur). </li></ol> 2. Kultur Vorbereitung und Mixing <ol><li> Waschen 1,5 ml der Kultur für jeden Stamm durch das Sammeln des Zellpellets durch Zentrifugation bei 17.000 × g für 30 Sekunden und Resuspendieren in 1 ml steriler 0,85% NaCl; Wiederholung einmal. </li><li> Pellet in 100 ul sterilem 0,85% NaCl. </li><li> Individuell vor Ort 10 ul gewaschene Kultur für jeden Stamm auf einer Ebene TY-Agar-Platte. Diese Punkte sind Steuer-Spots. </li><li> In 40 ul von jedem Stamm ohne den E. coli DH5 12 mit pJC2 in einem sterilen Röhrchen, mischen, und vor Ort 120 ul dieser Mischung auf einer Ebene TY-Agar-Platte. Dieser Spot ist der No-Integrase negative Kontrolle. </li><li> In 40 ul jedes Stammes in einem sterilen tube, mischen, und vor Ort 160 ul dieser Mischung auf einer Ebene TY-Agar-Platte. Dieser Spot ist der Punkt IMCE Paarung. </li><li> Willkommen Spots in einer Sterilbank trocknen. </li><li> Seal Platten und inkubieren bei 30 ° C über Nacht. </li></ol> 3. Isolierung von Trans-Integranten <ol><li> Streak-Steuerung und Flecken IMCE Spot auf TY-Agar-Platten mit 200 ug / ml Streptomycin (SmUW227 basiert auf Rm1021 Basis, die eine Mutation verleiht High-Level-Resistenz gegen Streptomycin 14 trägt) und 30 mu g / ml Gentamicin ergänzt. </li><li> Für die Berechnung der IMCE Effizienz, resuspendieren ca. ¼ der IMCE Paarung vor Ort in 500 ul steriler 0,85% NaCl. Machen Sie 10-fache serielle Verdünnungen bis 10 -7. Platten Verdünnungen 10 -2 bis 10 -5 auf TY-Agar-Platten mit 200 ug / ml Streptomycin und 30 mu g / ml Gentamicin, ergänzt um für trans-Integranten wählen. Platten Verdünnungen 10 -3 through 10 -7 auf TY-Agar-Platten mit 200 ug / ml Streptomycin, ergänzt um für beide trans-Integranten und potentiellen Empfängern, dh insgesamt Empfänger auszuwählen. </li><li> Für die Isolierung von trans-markerlosen Integranten resuspendieren etwa ein Viertel der IMCE Paarung vor Ort in 500 ul sterilem 0,85% NaCl. Make 10-fache serielle Verdünnungen bis 10 -6. Platten Verdünnungen 10 -4 bis 10 -6 auf vier TY Agarplatten mit 200 ug / ml Streptomycin und 200 ug / ml X-Gluc ergänzt. </li><li> Die Platten bei 30 ° C für 3 Tage. </li><li> Zeige RFP trans-Integranten unter grünem Licht (525 nm) und durch einen roten Filter (&gt; 610 nm) 15. </li><li> Berechnen Sie die prozentuale IMCE Effizienz als CFU von trans-Integranten der CFU von insgesamt Empfängern verglichen. Etwa die Hälfte der trans-Integranten wird wahr Kassette Austausch erfahren haben was sie weiß und Spectinomycin und Kleinschreibung. </li><li> Um die markerlosen trans-Integranten (w findenhier die Donor-Vektor nicht enthalten Gm r wie in pJH110)-Bildschirm für eine weiße Kolonie (ein erweiterter Inkubationszeit 1-2 zusätzliche Tage bei Raumtemperatur, wird die Differenzierung der Kolonien über X-gluc zu verbessern, ist dies notwendig, S. meliloti SmUW227), bestätigen der Kolonie Spectinomycin Empfindlichkeit durch Screening auf einer TY-Agarplatte ohne Antibiotika und einem TY-Agar-Platte mit 100 pg / ml Spectinomycin. </li></ol> 4. Repräsentative Ergebnisse Nach drei Tagen Inkubation auf TY mit Streptomycin und Gentamicin die Kontrolle Streifen sollte kein Wachstum. Die Streifen sollten IMCE konfluenten Wachstums auf dem Kopf Streifen und viele Kolonien auf dem zweiten Streifen, wie in 2 zu sehen. Die Effizienz des Transports Integration, als der Prozentsatz von trans-Integranten zu insgesamt Empfänger exprimiert, sollte im Bereich von 0,5%. Etwa die Hälfte der trans-Integranten wird Spectinomycin empfindliche und weißzeigen sie wahre Kassette Austausch unterzogen. Trans-Integranten, die die Tester RFP Spender Kassette aus pJH110 anzeigen soll erkennbar RFP Fluoreszenz, wenn sie unter grünem Licht (525 nm) und durch einen roten Filter (&gt; 610 nm) 15 angesehen. <img src="/files/ftp_upload/3698/3698fig1.jpg" alt="1"/> . 1 Konjugieren Mischung Darstellung: Mit Hilfe der Expression der Gene aus pRK600 Übertragung, werden alle Plasmide zufällig von Zelle zu Zelle übertragen. Diese Übertragung führt zur Erstellung von trans-Integranten in der Mischung, durch die LP-Belastung der Übernahme der beiden Plasmide für IMCE, die Integrase (int) Helferplasmid pJC2 und das Donorplasmid pJH110 erforderlich. Der Spender Kassette aus dem nicht-replizierenden Donorplasmid (pJH110) über ΦC31 Integrase-Aktivität mit den Markern der LP-Kassette auf dem Chromosom ausgetauscht, was zu einem Verlust der LP-Marker (Spr und uidA) und die Aufrechterhaltung des Spenders Kassette (RFP und Gm r) in der resultierenden trans-Integranten. <img src="/files/ftp_upload/3698/3698fig2.jpg" alt="2"/> Abbildung 2. A:. Mating Spot Platte auf einem nicht-selektiven TY Schild mit getrockneten Zell-Mischungen auf der Agar-Oberfläche B: Mating Flecken auf Streptomycin-Gentamicin-X-Gluc Platte ausgestrichen, von links oben keine Integrase-Regler im Uhrzeigersinn, IMCE in S. meliloti, E. coli DH5 mit pJC2 Kontrolle, E. coli DH5a mit pJH110 Kontrolle, E. coli MT616 Kontrolle, und S. . meliloti UW227 Kontrolle C: 10 -2 Verdünnung der Paarung Spot Resuspension auf TY Streptomycin-X-Gluc Agar D:. 10 -2 Verdünnung der Paarung Spot Resuspension auf TY-Streptomycin Gentamicin-X-Gluc-Agar (blaue Kolonien sind einzelne Rekombinanten, weiße Kolonien unterzogen wurden wahr. Kassettenaustausch) E: 10 -2 Verdünnung der Paarung Spot Resuspension auf TY Streptomycin-X-Gluc-Agar zeigt fehlende Fluoreszenz F:. 10 -2 Verdünnung der Paarung Spot Resuspension auf TY-Streptomycin Gentamicin-X-Gluc-Agar zeigt zwei Ebenen der Fluoreszenz (heller Kolonien, blaue Kolonien entsprechen und eine höhere Expression rfp vermutlich auf Lese-Promotor wenn von Vektorsequenz, wo Kolonien viele Veränderungen und-Kassettenaustausch enthalten RFP mit nur seinen unmittelbaren Promotor ohne Durchlese vom lac-Promotor in mit der Vektor ist die nicht vorhanden.).

<ol>
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Keine Interessenskonflikte erklärt.

Die IMCE Technik ermöglicht die effiziente Integration von einem einzigen attB flankiert DNA-Kassette in die LP-Locus eines zuvor entwickelten Stamm. Sobald das gewünschte Konstrukt anstelle der RFP, den Spender Kassette erstellen geklont wird, kommt die Technik nicht erforderlich, anschließende DNA-Reinigung und Transformation, so dass es sehr robust. Es ist wichtig, dass geeignete Wachstumsbedingungen Steuerelemente enthalten sind, sicher zu sein, die Resistenz gegen Antibiotika aufgrund der Erzeu...

<table border="1"><tbody><tr><td> Name des Reagenzes </td><td> Firma </td><td> Katalog-Nummer </td><td> Kommentare </td></tr><tr><td> Streptomycin </td><td> Bioshop Kanada Inc. </td><td> STP101 </td><td></td></tr><tr><td> Spectinomycin </td><td> Bioshop Kanada Inc. </td><td> <a href="https://ssl34.alentus.com/bioshopcanada/detail.asp?Pin=SPE201">SPE201</a> </td><td></td></tr><tr><td> Gentamicin </td><td> Bioshop Kanada Inc. </td><td> GTA202 </td><td></td></tr><tr><td> Chloramphenicol </td><td> Bioshop Kanada Inc. </td><td> CLR201 </td><td></td></tr><tr><td> Tetracycline </td><td> Bioshop Kanada Inc. </td><td> TET701 </td><td></td></tr><tr><td> Kanamycin </td><td> Bioshop Kanada Inc. </td><td> KAN201 </td><td></td></tr><tr><td> Bakteriologische Qualität Agar </td><td&gt; Bioshop Kanada Inc. </td><td> AGR001 </td><td></td></tr><tr><td> Trypton </td><td> Bioshop Kanada Inc. </td><td> TRP402 </td><td></td></tr><tr><td> Hefeextrakt </td><td> Bioshop Kanada Inc. </td><td> YEX401 </td><td></td></tr><tr><td> Kochsalz </td><td> Bioshop Kanada Inc. </td><td> SOD001 </td><td></td></tr><tr><td> Kalziumchlorid </td><td> Bioshop Kanada Inc. </td><td> CCL444 </td><td></td></tr><tr><td> X-gluc </td><td> Gold-Biotechnology Inc. </td><td> G1281C1 </td><td></td></tr><tr><td> E. coli-Stamm MT616 </td><td> Auf Anfrage erhältlich </td><td></td><td> Auch außerhalb unseres Labors verwendet </td></tr><tr><td> E. coli-Stamm pJC2 </td><td> Im Haus, auf Anfrage erhältlich </td><td></td><td></td></tr><tr><td> E. coli-Stamm pJH110 </td><td> Im Haus, verfügbar durch request </td><td></td><td></td></tr><tr><td> SmUW227 Belastung </td><td> Im Haus, auf Anfrage erhältlich </td><td></td><td></td></tr></tbody></table>

site-specific bacterial chromosome engineering: &#934;c31 integrase mediated cassette exchange (imce)

Die Bakterien-Chromosom kann verwendet werden, um stabil zu halten Fremd-DNA in der Mega-Basen-Bereich 1 werden. Integration in das Chromosom umgeht Themen wie Plasmidreplikation, der Stabilität von Plasmiden, Plasmid Inkompatibilität und Plasmid-Kopienzahl Varianz. Diese Methode verwendet die ortsspezifische Integrase aus dem Streptomyces Phagen (Φ) C31 2,3. Die Integrase katalysiert ΦC31 eine direkte Rekombination zwischen zwei spezifischen DNA-sites: attB und attP (34 und 39 bp) 4. Diese Rekombination ist stabil und nicht zurückkehren 5. Ein &quot;Landeplatz&quot; (LP)-Sequenz bestehend aus einer Spectinomycin-Resistenz-Gen, aadA (SPR) und der E. coli ß-Glucuronidase-Gen (uidA) von attP flankiert in die Chromosomen der Sinorhizobium meliloti, Ochrobactrum anthropi und Agrobacterium tumefaciens in einem Zwischengenregion integriert wurde, bin daspC Locus und die tetA Locus, jeweils. S. meliloti ist in diesem Protokoll verwendet. Mobilisierbaren Vektoren, die Donor attB flankieren eine Stuffer rot fluoreszierendes Protein (RFP)-Gen und ein Antibiotika-Resistenz-Gen wurde ebenfalls konstruiert. In diesem Beispiel wird Gentamicin resistente Plasmid pJH110 verwendet wird. Der RFP-Gen 6 kann mit einem gewünschten Konstrukt mit Sph I und Pst I ersetzt werden Alternativ kann ein synthetisches Konstrukt von attB-Stellen flankiert sein können subkloniert in einen mobilisierbaren Vektor wie pK19mob 7. Die Expression des Integrase-Gens ΦC31 (kloniert von pHS62 8) durch den lac-Promotor angetrieben wird, auf einem mobilisierbaren Plasmids mit breitem Wirtsbereich pRK7813 9. Ein tetraparental passenden Protokoll wird verwendet, um den Spender Kassette in der LP-Stamm und ersetzt die Marker in der LP-Sequenz mit der Donor-Kassette zu übertragen. Diese Zellen sind trans-Integranten. Trans-Integranten werden mit einem typischen Wirkungsgrad von 0,5% gebildet. Trans-Integranten werden typischerweise innerhalb der ersten 500-1,000 Kolonien durch Antibiotika-Empfindlichkeit oder blau-Weiß-Screening unter Verwendung von 5-Brom-4-chlor-3-indolyl-beta-D-Glucuronsäure (X-gluc) gescreent vorhanden. Dieses Protokoll enthält die Paarungs-und Auswahlverfahren für das Erstellen und Isolieren von trans-Integranten.

Watch this Scientific Journal Video about Site-specific Bacterial Chromosome Engineering: Î¦C31 Integrase Mediated Cassette Exchange IMCE at JoVE.com

Site-specific Bacterial Chromosome Engineering: &amp;#934;C31 Integrase Mediated Cassette Exchange (IMCE)

Eine schnelle und effiziente Methode, um Fremd-DNA von Interesse in vorgefertigte Akzeptor Stämme, sogenannte Landing-Pad-Stämme, die Integration beschrieben wird. Das Verfahren erlaubt eine ortsspezifische Integration eines DNA-Kassette in die gentechnisch Landeplatz Ort einer gegebenen Dehnung, durch Konjugation und Expression des ΦC31 Integrase.

Site-spezifische bakterielle Chromosom Engineering: ΦC31 Integrase vermittelte Cassette Exchange (IMCE)

The bacterial chromosome may be used to stably maintain foreign DNA in the mega-base range1. Integration into the chromosome circumvents issues such as ...

site-specific-bacterial-chromosome-engineering-c31-integrase-mediated

Research

JoVE Journal

Bioengineering

Site-specific Bacterial Chromosome Engineering: &#934;C31 Integrase Mediated Cassette Exchange (IMCE)

15.5K Aufrufe.  University of Waterloo. Eine schnelle und effiziente Methode, um Fremd-DNA von Interesse in vorgefertigte Akzeptor Stämme, sogenannte Landing-Pad-Stämme, die Integration beschrieben wird. Das Verfahren erlaubt eine ortsspezifische Integration eines DNA-Kassette in die gentechnisch Landeplatz Ort einer gegebenen Dehnung, durch Konjugation und Expression des ΦC31 Integrase.

Serie: Site-specific Bacterial Chromosome Engineering: &#934;C31 Integrase Mediated Cassette Exchange (IMCE)

Procedure for Lung Engineering

Lung tissue, including lung cancer and chronic lung diseases such as chronic obstructive pulmonary disease, cumulatively account for some 280,000 deaths annually; chronic obstructive pulmonary disease is currently the fourth leading cause of death in the United States1. Contributing to this mortality is the fact that lungs do not generally repair or regenerate beyond the microscopic, cellular level. Therefore, lung tissue that is damaged by degeneration or infection, or lung tissue that is surgically resected is not functionally replaced in vivo. To explore whether lung tissue can be generated in vitro, we treated lungs from adult rats using a procedure that removes cellular components to produce an acellular lung extracellular matrix scaffold. This scaffold retains the hierarchical branching structures of airways and vasculature, as well as a largely intact basement membrane, which comprises collagen IV, laminin, and fibronectin. The scaffold is mounted in a bioreactor designed to mimic critical aspects of lung physiology, such as negative pressure ventilation and pulsatile vascular perfusion. By culturing pulmonary epithelium and vascular endothelium within the bioreactor-mounted scaffold, we are able to generate lung tissue that is phenotypically comparable to native lung tissue and that is able to participate in gas exchange for short time intervals (45-120 minutes). These results are encouraging, and suggest that repopulation of lung matrix is a viable strategy for lung regeneration. This possibility presents an opportunity not only to work toward increasing the supply of lung tissue for transplantation, but also to study respiratory cell and molecular biology in vitro for longer time periods and in a more accurate microenvironment than has previously been possible.

We have developed a decellularized lung extracellular matrix and novel biomimetic bioreactor that can be used to generate functional lung tissue. By seeding cells into the matrix and culturing in the bioreactor, we generate tissue that demonstrates effective gas exchange when transplanted in vivo for short periods of time.

Vorgehensweise für Lung Technik

Lung tissue, including lung cancer and chronic lung diseases such as chronic obstructive pulmonary disease, cumulatively account for some 280,000 deaths ...

Forschung

Biotechnik

Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry (SESI-MS)

Secondary electrospray ionization mass spectrometry (SESI-MS) is a method developed for the rapid detection of volatile compounds, without the need for sample pretreatment. The method was first described by Fenn and colleagues1 and has been applied to the detection of illicit drugs2 and explosives3-4, the characterization of skin volatiles5, and the analysis of breath6-7.
SESI ionization occurs by proton transfer reactions between the electrospray solution and the volatile analyte, and is therefore suitable for the analysis of hetero-organic molecules, just as in traditional electrospray ionization (ESI). However, unlike standard ESI, the proton transfer process of SESI occurs in the vapor phase rather than in solution (Fig. 1), and therefore SESI is best suited for detecting organic volatiles and aerosols.
We are expanding the use of SESI-MS to the detection of bacterial volatiles as a method for bacterial identification and characterization8. We have demonstrated that SESI-MS volatile fingerprinting, combined with a statistical analysis method, can be used to differentiate bacterial genera, species, and mixed cultures in a variety of growth media.8 Here we provide the steps for obtaining bacterial volatile fingerprints using SESI-MS, including the instrumental parameters that should be optimized to ensure robust bacterial identification and characterization.

Characterizing Bacterial Volatiles using Secondary Electrospray Ionization Mass Spectrometry SESI-MS

Secondary electrospray ionization mass spectrometry (SESI-MS) enables the detection of volatile organic compounds (VOCs) without the need for any sample pretreatment. This protocol provides instructions for the rapid (within minutes) characterization of bacterial VOCs using SESI-MS.

Charakterisierung Bakterielle Flüchtige mit Secondary Elektrospray-Ionisation-Massenspektrometrie (SESI-MS)

Secondary electrospray ionization mass spectrometry (SESI-MS) is a method developed for the rapid detection of volatile compounds, without the need for ...

High efficiency, Site-specific Transfection of Adherent Cells with siRNA Using Microelectrode Arrays (MEA)

The discovery of RNAi pathway in eukaryotes and the subsequent development of RNAi agents, such as siRNA and shRNA, have achieved a potent method for silencing specific genes1-8 for functional genomics and therapeutics. A major challenge involved in RNAi based studies is the delivery of RNAi agents to targeted cells. Traditional non-viral delivery techniques, such as bulk electroporation and chemical transfection methods often lack the necessary spatial control over delivery and afford poor transfection efficiencies9-12. Recent advances in chemical transfection methods such as cationic lipids, cationic polymers and nanoparticles have resulted in highly enhanced transfection efficiencies13. However, these techniques still fail to offer precise spatial control over delivery that can immensely benefit miniaturized high-throughput technologies, single cell studies and investigation of cell-cell interactions. 
Recent technological advances in gene delivery have enabled high-throughput transfection of adherent cells14-23, a majority of which use microscale electroporation. Microscale electroporation offers precise spatio-temporal control over delivery (up to single cells) and has been shown to achieve high efficiencies19, 24-26. Additionally, electroporation based approaches do not require a prolonged period of incubation (typically 4 hours) with siRNA and DNA complexes as necessary in chemical based transfection methods and lead to direct entry of naked siRNA and DNA molecules into the cell cytoplasm. As a consequence gene expression can be achieved as early as six hours after transfection27. Our lab has previously demonstrated the use of microelectrode arrays (MEA) for site-specific transfection in adherent mammalian cell cultures17-19. In the MEA based approach, delivery of genetic payload is achieved via localized micro-scale electroporation of cells. An application of electric pulse to selected electrodes generates local electric field that leads to electroporation of cells present in the region of the stimulated electrodes. The independent control of the micro-electrodes provides spatial and temporal control over transfection and also enables multiple transfection based experiments to be performed on the same culture increasing the experimental throughput and reducing culture-to-culture variability. 
Here we describe the experimental setup and the protocol for targeted transfection of adherent HeLa cells with a fluorescently tagged scrambled sequence siRNA using electroporation. The same protocol can also be used for transfection of plasmid vectors. Additionally, the protocol described here can be easily extended to a variety of mammalian cell lines with minor modifications. Commercial availability of MEAs with both pre-defined and custom electrode patterns make this technique accessible to most research labs with basic cell culture equipment.

High efficiency, Site-specific Transfection of Adherent Cells with siRNA Using Microelectrode Arrays MEA

The article details the protocol for site-specific transfection of scrambled sequence of siRNA in an adherent mammalian cell culture using a microelectrode array (MEA).

Hohe Effizienz, Site-spezifische Transfektion adhärenter Zellen mit siRNA mit Mikroelektroden-Arrays (MEA)

The discovery of RNAi pathway in eukaryotes and the subsequent development of RNAi agents, such as siRNA and shRNA, have achieved a potent method for ...

Capillary Force Lithography for Cardiac Tissue Engineering

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical discoveries with the aims of developing functional tissues for cardiac regeneration as well as in vitro screening assays. However, the ability to create high-fidelity models of heart tissue has proven difficult. The heart&#8217;s extracellular matrix (ECM) is a complex structure consisting of both biochemical and biomechanical signals ranging from the micro- to the nanometer scale2. Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering3-5.
A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling2. Unfortunately, few methods have been able to mimic the organization of ECM fibers down to the nanometer scale. Recent advancements in nanofabrication techniques, however, have enabled the design and fabrication of scalable scaffolds that mimic the in vivo structural and substrate stiffness cues of the ECM in the heart6-9.
Here we present the development of two reproducible, cost-effective, and scalable nanopatterning processes for the functional alignment of cardiac cells using the biocompatible polymer poly(lactide-co-glycolide) (PLGA)8 and a polyurethane (PU) based polymer. These anisotropically nanofabricated substrata (ANFS) mimic the underlying ECM of well-organized, aligned tissues and can be used to investigate the role of nanotopography on cell morphology and function10-14.
Using a nanopatterned (NP) silicon master as a template, a polyurethane acrylate (PUA) mold is fabricated. This PUA mold is then used to pattern the PU or PLGA hydrogel via UV-assisted or solvent-mediated capillary force lithography (CFL), respectively15,16. Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip and the PUA mold is placed on top. For UV-assisted CFL, the PU is then exposed to UV radiation (&#955; = 250-400 nm) for curing. For solvent-mediated CFL, the PLGA is embossed using heat (120 &#176;C) and pressure (100 kPa). After curing, the PUA mold is peeled off, leaving behind an ANFS for cell culture. Primary cells, such as neonatal rat ventricular myocytes, as well as human pluripotent stem cell-derived cardiomyocytes, can be maintained on the ANFS2.

In this protocol, we demonstrate the fabrication of biomimetic cardiac cell culture substrata made from two distinct polymeric materials using capillary force lithography. The described methods provide a scalable, cost-effective technique to engineer the structure and function of macroscopic cardiac tissues for in vitro and in vivo applications.

Kapillar-Force-Lithographie für Herz-Tissue Engineering

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical ...

Observing and Quantifying Fibroblast-mediated Fibrin Gel Compaction

Cells embedded in collagen and fibrin gels attach and exert traction forces on the fibers of the gel. These forces can lead to local and global reorganization and realignment of the gel microstructure. This process proceeds in a complex manner that is dependent in part on the interplay between the location of the cells, the geometry of the gel, and the mechanical constraints on the gel. To better understand how these variables produce global fiber alignment patterns, we use time-lapse differential interference contrast (DIC) microscopy coupled with an environmentally controlled bioreactor to observe the compaction process between geometrically spaced explants (clusters of fibroblasts). The images are then analyzed with a custom image processing algorithm to obtain maps of the strain. The information obtained from this technique can be used to probe the mechanobiology of various cell-matrix interactions, which has important implications for understanding processes in wound healing, disease development, and tissue engineering applications.

Time-lapse microscopy and image processing techniques were used to observe and analyze fibroblast-mediated gel compaction and fibrin fiber realignment in an environmentally controlled bioreactor over a 48 hr&#160;period.

Beobachtung und Quantifizierung von Fibroblasten-vermittelter Fibrin-Gelverdichtung

Cells embedded in collagen and fibrin gels attach and exert traction forces on the fibers of the gel. These forces can lead to local and global ...

Manufacturing Of Robust Natural Fiber Preforms Utilizing Bacterial Cellulose as Binder

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, holding the loose natural fibers together.
Our method is specially suited for the manufacturing of rigid and robust preforms of hydrophilic fibers. The porous and hydrophilic nature of such fibers results in significant water uptake, drawing in the bacterial cellulose dispersed in the suspension. The bacterial cellulose will then be filtered against the surface of these fibers, forming a bacterial cellulose coating. When the loose fiber-bacterial cellulose suspension is filtered and dried, the adjacent bacterial cellulose forms a network and hornified to hold the otherwise loose fibers together.
The introduction of bacterial cellulose into the preform resulted in a significant increase of the mechanical properties of the fiber preforms. This can be attributed to the high stiffness and strength of the bacterial cellulose network. With this preform, renewable high performance hierarchical composites can also be manufactured by using conventional composite production methods, such as resin film infusion (RFI) or resin transfer molding (RTM). Here, we also describe the manufacturing of renewable hierarchical composites using double bag vacuum assisted resin infusion.

We present a novel method of manufacturing rigid and robust short natural fiber preforms using a papermaking process. Bacterial cellulose acts simultaneously as the binder for the loose fibers and provides rigidity to the fiber preforms. These preforms can be infused with a resin to produce truly green hierarchical composites.

Herstellung von robusten Naturfaser-Preforms Verwendung Bakteriencellulose als Binder

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose ...

Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii

The particular bacterium under investigation here (S. pasteurii) is unique in its ability, under the right conditions, to induce the hydrolysis of urea (ureolysis) in naturally occurring environments through secretion of an enzyme urease. This process of ureolysis, through a chain of chemical reactions, leads to the formation of calcium carbonate precipitates. This is known as Microbiologically Induced Calcite Precipitation (MICP). The proper culture protocols for MICP are detailed here. Finally, visualization experiments under different modes of microscopy were performed to understand various aspects of the precipitation process. Techniques like optical microscopy, Scanning Electron Microscopy (SEM) and X-Ray Photo-electron Spectroscopy (XPS)&#160;were employed to chemically characterize the end-product. Further, the ability of these precipitates to clog pores inside a natural porous medium was demonstrated through a qualitative experiment where sponge bars were used to mimic a pore-network with a range of length scales. A sponge bar dipped in the culture medium containing the bacterial cells hardens due to the clogging of its pores resulting from the continuous process of chemical precipitation. This hardened sponge bar exhibits superior strength when compared to a control sponge bar which becomes compressed and squeezed under the action of an applied external load, while the hardened bar is able to support the same weight with little deformation.

Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii

Protocols for microbiologically induced calcite precipitation (MICP) using the bacterium Sporosarcina pasteurii are presented here. The precipitated calcium carbonate was characterized through optical microscopy and scanning electron microscopy (SEM). It is also shown that exposure to MICP increases the compressive strength of sponge.

Mikrobiologisch Induzierte Calcitausfällung Vermittelt durch<em&gt; Sporosarcina pasteurii</em

The particular bacterium under investigation here (S. pasteurii) is unique in its ability, under the right conditions, to induce the hydrolysis of urea ...

Tissue Engineering by Intrinsic Vascularization in an In Vivo Tissue Engineering Chamber

In reconstructive surgery, there is a clinical need for an alternative to the current methods of autologous reconstruction which are complex, costly and trade one defect for another. Tissue engineering holds the promise to address this increasing demand. However, most tissue engineering strategies fail to generate stable and functional tissue substitutes because of poor vascularization. This paper focuses on an in vivo tissue engineering chamber model of intrinsic vascularization where a perfused artery and a vein either as an arteriovenous loop or a flow-through pedicle configuration is directed inside a protected hollow chamber. In this chamber-based system angiogenic sprouting occurs from the arteriovenous vessels and this system attracts ischemic and inflammatory driven endogenous cell migration which gradually fills the chamber space with fibro-vascular tissue. Exogenous cell/matrix implantation at the time of chamber construction enhances cell survival and determines specificity of the engineered tissues which develop. Our studies have shown that this chamber model can successfully generate different tissues such as fat, cardiac muscle, liver and others. However, modifications and refinements are required to ensure target tissue formation is consistent and reproducible. This article describes a standardized protocol for the fabrication of two different vascularized tissue engineering chamber models in vivo.

Tissue Engineering by Intrinsic Vascularization in an In Vivo Tissue Engineering Chamber

This is a guideline for constructing in vivo vascularized tissue using a microsurgical arteriovenous loop or a flow-through pedicle configuration inside a tissue engineering chamber. The vascularized tissues generated can be employed for organ regeneration and replacement of tissue defects, as well as for drug testing and disease modeling.

Tissue Engineering von Intrinsic Vaskularisation in ein<em&gt; In Vivo</em&gt; Tissue Engineering Chamber

In reconstructive surgery, there is a clinical need for an alternative to the current methods of autologous reconstruction which are complex, costly and ...

Microfluidic Buffer Exchange for Interference-free Micro/Nanoparticle Cell Engineering

Engineering cells with active-ingredient-loaded micro/nanoparticles (NPs) is becoming an increasingly popular method to enhance native therapeutic properties, enable bio imaging and control cell phenotype. A critical yet inadequately addressed issue is the significant number of particles that remain unbound after cell labeling which cannot be readily removed by conventional centrifugation. This leads to an increase in bio imaging background noise and can impart transformative effects onto neighboring non-target cells. In this protocol, we present an inertial microfluidics-based buffer exchange strategy termed as Dean Flow Fractionation (DFF) to efficiently separate labeled cells from free NPs in a high throughput manner. The developed spiral microdevice facilitates continuous collection (&#62;90% cell recovery) of purified cells (THP-1 and MSCs) suspended in new buffer solution, while achieving &#62;95% depletion of unbound fluorescent dye or dye-loaded NPs (silica or PLGA). This single-step, size-based cell purification strategy enables high cell processing throughput (106 cells/min) and is highly useful for large-volume cell purification of micro/nanoparticle engineered cells to achieve interference-free clinical application.

This protocol describes the use of an inertial microfluidics-based buffer exchange strategy to purify micro/nanoparticle engineered cells with efficient depletion of unbound particles.

Mikrofluidik-Pufferaustausch für einen störungsfreien Micro / Nanoparticle Zelltechnik

Engineering cells with active-ingredient-loaded micro/nanoparticles (NPs) is becoming an increasingly popular method to enhance native therapeutic ...

Light-mediated Formation and Patterning of Hydrogels for Cell Culture Applications

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In particular, light-mediated click reactions, such as photoinitiated thiol&#8722;ene and thiol&#8722;yne reactions, afford spatiotemporal control over material properties and allow the design of systems with a high degree of user-directed property control. Fabrication and modification of hydrogel-based biomaterials using the precision afforded by light and the versatility offered by these thiol&#8722;X photoclick chemistries are of growing interest, particularly for the culture of cells within well-defined, biomimetic microenvironments. Here, we describe methods for the photoencapsulation of cells and subsequent photopatterning of biochemical cues within hydrogel matrices using versatile and modular building blocks polymerized by a thiol&#8722;ene photoclick reaction. Specifically, an approach is presented for constructing hydrogels from allyloxycarbonyl (Alloc)-functionalized peptide crosslinks and pendant peptide moieties and thiol-functionalized poly(ethylene glycol) (PEG) that rapidly polymerize in the presence of lithium acylphosphinate photoinitiator and cytocompatible doses of long wavelength ultraviolet (UV) light. Facile techniques to visualize photopatterning and quantify the concentration of peptides added are described. Additionally, methods are established for encapsulating cells, specifically human mesenchymal stem cells, and determining their viability and activity. While the formation and initial patterning of thiol-alloc hydrogels are shown here, these techniques broadly may be applied to a number of other light and radical-initiated material systems (e.g., thiol-norbornene, thiol-acrylate) to generate patterned substrates.

We describe a sequential process for light-mediated formation and subsequent biochemical patterning of synthetic hydrogel matrices for three-dimensional cell culture applications. The construction and modification of hydrogels with cytocompatible photoclick chemistry is demonstrated. Additionally, facile techniques to quantify and observe patterns and determine cell viability within these hydrogels are presented.

Licht-vermittelte Bildung und Musterung von Hydrogelen für Zellkulturanwendungen

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In ...