Mittel aus dem Wellcome Trust wird freundlicherweise bestätigt (Förderkennzeichen 085245/Z/08/Z). Nottingham Nanotechnologie und Nanowissenschaften Centre freundlicherweise für den Zugang zu den Raman-System und für die East Midlands Development Agency für die Finanzierung dieser Geräte anerkannt.

<ol>
	<li>Hook, A. L., Anderson, D. G., Langer, R., Williams, P., Davies, M. C., Alexander, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+throughput+methods+applied+in+biomaterial+development+and+discovery.">High throughput methods applied in biomaterial development and discovery.</a> Biomaterials. 31, 187-198 (2010).</li><li>Anderson, D. G., Levenberg, S., Langer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoliter-scale+synthesis+of+arrayed+biomaterials+and+application+to+human+embryonic+stem+cells.">Nanoliter-scale synthesis of arrayed biomaterials and application to human embryonic stem cells.</a> Nature Biotechnology. 22, 863-866 (2004).</li><li>Mei, Y., Saha, K., Bogatyrev, S. R., Yang, J., Hook, A. L., Kalcioglu, Z. I., Cho, S. W., Mitalipova, M., Pyzocha, N., Rojas, F., Van Vliet, K. J., Davies, M. C., Alexander, M. R., Langer, R., Jaenisch, R., Anderson, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combinatorial+development+of+biomaterials+for+clonal+growth+of+human+pluripotent+stem+cells.">Combinatorial development of biomaterials for clonal growth of human pluripotent stem cells.</a> Nature Materials. 9, 768-778 (2010).</li><li>Pernagallo, S., Wu, M., Gallagher, M. P., Bradley, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colonising+new+frontiers-microarrays+reveal+biofilm+modulating+polymers.">Colonising new frontiers-microarrays reveal biofilm modulating polymers.</a> Journal of Materials Chemistry. 21, 96-101 (2011).</li><li>Yang, J., Mei, Y., Hook, A. L., Taylor, M., Urquhart, A. J., Bogatyrev, S. R., Langer, R., Anderson, D. G., Davies, M. C., Alexander, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer+surface+functionalities+that+control+human+embryoid+body+cell+adhesion+revealed+by+high+throughput+surface+characterization+of+combinatorial+material+microarrays.">Polymer surface functionalities that control human embryoid body cell adhesion revealed by high throughput surface characterization of combinatorial material microarrays.</a> Biomaterials. 31, 8827-8838 (2010).</li><li>Urquhart, A. J., Anderson, D. G., Taylor, M., Alexander, M. R., Langer, R., Davies, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+throughput+surface+characterisation+of+a+combinatorial+material+library.">High throughput surface characterisation of a combinatorial material library.</a> Advanced Materials. 19, 2486-2491 (2007).</li><li>Taylor, M., Urquhart, A. J., Zelzer, M., Davies, M. C., Alexander, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Picoliter+water+contact+angle+measurement+on+polymers.">Picoliter water contact angle measurement on polymers.</a> Langmuir. 23, 6875-6878 (2007).</li><li>Urquhart, A. J., Taylor, M., Anderson, D. G., Langer, R., Davies, M. C., Alexander, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TOF-SIMS+analysis+of+a+576+micropatterned+copolymer+array+to+reveal+surface+moieties+that+control+wettability.">TOF-SIMS analysis of a 576 micropatterned copolymer array to reveal surface moieties that control wettability.</a> Analytical Chemistry. 80, 135-142 (2008).</li><li>Hook, A. L., Yang, J., Chen, X., Roberts, C. J., Mei, Y., Anderson, D. G., Langer, R., Alexander, M. R., Davies, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acrylate+polymers+with+hydro-responsive+topography.">Acrylate polymers with hydro-responsive topography.</a> Soft Matter. 7, 7194-9197 (2011).</li><li>Pernagallo, S., Unciti-Broceta, A., Diaz-Mochon, J. J., Bradley, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deciphering+cellular+morphology+and+biocompatibility+using+polymer+microarrays.">Deciphering cellular morphology and biocompatibility using polymer microarrays.</a> Biomedical Materials. 3, (2008).</li></ol>

Wir haben nichts zu offenbaren.

Polymer-Microarrays wurden erfolgreich für die Entdeckung neuer Materialien durch Screening Hunderte von neuartigen Polymer in einem biologischen Assay verwendet und Identifizierung &quot;Treffer&quot; Materialien, die anschließend bis zu nützlichen Geräten skaliert werden kann. In diesem Fall kann die Charakterisierung von Oberflächen beschrieben eingesetzt anschließenden werden, um die biologische Assays und ausschließlich auf den &quot;Hit&quot;-Materialien, die Materialien genauer zu untersuchen. Diese Strategie kann von Interesse sein, wenn HTSL nicht verfügbar ist der Experimentator Verwendung dieses Ansatzes. Jedoch voll auszunutzen Polymer Mikroarrays zu studieren biologische Material-Interaktionen das gesamte Array von Hunderten von Materialien ist vor der biologischen Assays mit HTSL Methodiken, die anschließend verwendet werden, um Struktur-Funktions allgemeinen Trends beobachten sein können analysiert werden. Kontakt Drucken basiert auf den Metallstift Schiebetüren oben und unten frei im Stifthalter. Pin-und Stifthalter Sauberkeit ist von größter Bedeutung ist die Gewährleistung pRUCKEN tritt erfolgreich und sollten konsequent durchgeführt werden. Vor Beginn ein Druckvorgang ausgeführt passende Bewegung des Stiftes innerhalb des Stifthalters kann durch Ausführen eines Testlaufs getestet werden, ohne vorhandenen Monomeren. Der Reinigungsschritt ist fortzusetzen, bis der Stift Bewegung reproduzierbar erreicht wird. Beträchtliche Gedankens soll in das Design des Monomergemisches gehen. Um leicht eine kombinatorische Bibliothek von Polymeren sind Hunderte von Copolymeren durch Mischen einige Monomere in unterschiedlichen Verhältnissen gebildet. Typischerweise produzieren wir 576 Mitgliedsbibliotheken da dies bildet eine 24 x 24-Array, das geeignet für die Geometrie eines Glasobjektträger ist. Um eine kombinatorische Bibliothek, die meisten kombinatorischen Raum ist es am einfachsten zu 24 Monomere im Verhältnis 2:1 mischen paarweise untersucht produzieren. Alternativ sind die Einbeziehung der Gradienten der Zusammensetzung innerhalb der Anordnung zur Freigabe der Beobachtungen von Trends, die optimale Monomerzusammensetzungen bis d sein können nützlichetermined. Als ein Beispiel für diese 22 Monomere können als erste Komponente in einem Co-Monomer-Mischung, die nacheinander mit 1 von 6 ist die zweite Komponente verdünnt verwendet werden. Wenn 5 Verdünnungen eingesetzt werden, beispielsweise Mischen der ersten und zweiten Komponenten in Verhältnissen von 90:10, 75:25, 50:50, 25:75 und 10:90, würde dies zu 488 einzigartige Copolymerlösungen führen. Um die gesamte bringen bis zu 576, repliziert der Homopolymerisate der Monomeren verwendet eingeführt werden kann, was oft ein wichtiger Referenzprobe. 576 Monomerlösungen sollte in 2 384-Well-Platten verzichtet werden. Für die Programmierung des Roboters es einfacher ist, zwei identische Platten in Bezug auf die Position der Monomere haben somit die Monomerlösungen gleichmäßig zwischen den zwei Platten aufgeteilt werden. Eine erhebliche Menge an Zeit können bei der Herstellung der Source Platten durch die Verwendung von Mehrkanal gespeichert werden, und das Design der Quelle Platten sollte bestimmt werden, um die Verwendung der Mehrkanalpipetten auszunutzen. &lt;/ P&gt; Um maschinelle und automatische HTSL der Arrays erreichen die Kassaposition muss erfolgreich mit der Charakterisierung Vorrichtung ausgerichtet werden. Typischerweise wird die Tonhöhe einer Acrylat-Array ist 500-1000 um und das Polymer Fleckdurchmesser von 300 um. Die meisten Kreuztische haben eine Auflösung von weniger als 10 um, damit eine ausreichende Toleranz für die Charakterisierung von Oberflächen Vorrichtung zur zuverlässigen Zugriff auf die Array-Positionen, wenn die richtigen Abmessungen eingegeben wurden, um die Positionierung der Probe Software. Die Beschränkung auf die automatisierte Positionierung ist in der Tat das genaues Drucken des Arrays. Um genaue Drucken zu gewährleisten ist es wichtig, um die Bewegung des Substrats auf dem Drucktisch verhindern entweder mittels Vakuumansaugung oder Federklemmen zusammen mit entsprechenden Abmessungen Schieber (beachte, dass sowohl ein US-Standard und EU Foliengröße existieren). ToF-SIMS ist ein extrem oberflächensensitive Technik, eine Kontamination von Proben beobachten können. Somit muss darauf geachtet werden, upmostden Kontakt mit der Oberfläche zu vermeiden. Die Proben sollten nur bearbeitet werden, aber die Oberfläche von Interesse nicht kontaktiert, mit sauberen Handschuhen (vorzugsweise Polyethylen) und mit frisch gereinigten Pinzetten. Wir in der Regel mit Chloroform und Hexan waschen. Probenspeicher vor den Messungen wird am besten in einem Probenhalter mit den Folien auseinander hält geschieht beispielsweise das 5 Objektträgerhalter oder 20 Objektträgerhalter. Die Arrays sind speziell auf Kompatibilität mit vielen biologischen Testformate und Auslesungen, dh entworfen, ist das verwendete Substrat ein Objektträger idealerweise zur Fluoreszenz-Scanner und Lichtmikroskopen geeignet. Dies bedeutet, das Format ist gut zu erkunden vielen Material-biologischen Wechselwirkungen geeignet. Weiterhin erlaubt das Format Hunderte von Materialien parallel gescreent werden. Dies ermöglicht viele weitere Materialien als herkömmliche Methoden, wobei jede neue Materialchemie einzeln abgeschirmt abgeschirmt werden. Die erhöhte Spielraum für biologisch-Materie-Wechselwirkungen ermöglichens für die Aufklärung der Mechanismen der biologischen Oberflächen-Wechselwirkungen sowie das Finden der optimalen Material für eine bestimmte Anwendung.

<table border="1"><tbody><tr><td> Name des Reagenz / Ausrüstung </td><td> Firma </td><td> Katalog / Modellnummer </td></tr><tr><td> Epoxy Dias </td><td> Genetix </td><td> K2652 </td></tr><tr><td> Kontakt Drucker </td><td> Biodot </td><td> XYZ3060 Platform </td></tr><tr><td> Metallstift </td><td> Arrayit </td><td> 946MP6B </td></tr><tr><td> ToF-SIMS Instrument </td><td> ION-TOF </td><td></td></tr><tr><td> XPS Instrument </td><td> Kratos </td><td></td></tr><tr><td> WCA Gerät </td><td> Krüss </td><td> DSA 100 </td></tr><tr><td> AFM </td><td> Bruker </td><td> Dimension Icon </td></tr><tr><td> RPMI-1640 Zellkulturmedien </td><td> Sigma-Aldrich </td><td> R0883 </td></tr><tr><td> SYTO17 </td><td> Invitrogen </td><td> S-7579 </td></tr></tbody></table>

polymer microarrays for high throughput discovery of biomaterials

Mischen ist eine Grundoperation, die zwei oder mehr Komponenten kombiniert zu einer homogenen Mischung. Diese Arbeit umfasst Mischen von zwei viskosen flüssigen Ströme unter Verwendung eines statischen Inline-Mischer. Der Mischer ist ein Split-and-rekombinieren Design, Scher-und Dehnströmung beschäftigt, um die Grenzflächen Kontakt zwischen den Bauteilen zu erhöhen. Ein Prototyp Split-and-rekombinieren (SAR)-Mischer wurde durch Ausrichten einer Reihe von dünnen lasergeschnittenen Poly (Methylmethacrylat) (PMMA) Platten an seinem Platz gehalten in einem PVC-Rohr ausgebildet ist. Mischen in dieser Vorrichtung ist in der Photographie in Abb. Ein. Rote Farbstoff wurde zu einem Abschnitt der Testflüssigkeit hinzugefügt und als Nebenkomponente in die größeren (ungefärbten)-Komponente gemischt. Am Eingang des Mischers wird der eingespritzte Schicht aus Tracer Fluid in zwei Schichten aufgeteilt, während es durch die Mischstrecke mündet. Bei jeder nachfolgenden Mischabschnitt, wird die Anzahl der horizontalen Schichten dupliziert. Letztlich wird die einzelnen Strom von Farbstoff gleichmäßig dispergiert throughout den Querschnitt der Vorrichtung. Verwendung einer nicht-Newtonschen Prüffluid von 0,2% Carbopol und einem dotierten Tracer Fluid von ähnlicher Zusammensetzung, das Mischen in der Einheit visualisiert mittels Magnetresonanztomographie (MRT). MRT ist eine sehr mächtige experimentelle Sonde molekularen chemischen und physikalischen Umwelt sowie Probe-Struktur auf der Längenskala von Mikrometern bis Zentimetern. Diese Empfindlichkeit hat in breiten Anwendung dieser Techniken führte zu physikalischen, chemischen und / oder biologischen Eigenschaften von Materialien, angefangen von Menschen Lebensmittel zu porösen Medien 1, 2 charakterisieren. Die Anlagen und Bedingungen welche hier eignen sich zum Abbilden enthaltenden Flüssigkeiten erhebliche Mengen an mobilen NMR 1 H wie gewöhnliches Wasser und organische Flüssigkeiten, einschließlich Ölen. Traditionell MRI hat supraleitenden Magneten, die nicht geeignet sind für industrielle Umgebungen und nicht tragbaren innerhalb eines Labors (Abb. 2) eingesetzt. Jüngste Fortschritte in-Magnet-Technologie haben den Bau von großvolumigen industrietaugliche Magneten für bildgebende Prozessabläufe gestattet. Dabei sieht MRI räumlich aufgelösten Komponente Konzentrationen an verschiedenen axialen Stellen während des Mischprozesses. Diese Arbeit dokumentiert Echtzeit Mischen von hochviskosen Flüssigkeiten über distributive Mischen mit einem Antrag auf Körperpflegeprodukte.

Watch this Scientific Journal Video about Polymer Microarrays for High Throughput Discovery of Biomaterials at JoVE.com

Polymer Microarrays for High Throughput Discovery of Biomaterials

Eine Beschreibung der Bildung eines Polymers unter Verwendung eines Mikroarray-on-Chip-Technik Photopolymerisation. Der hohe Durchsatz Oberflächencharakterisierung mittels Rasterkraftmikroskopie, Wasser Randwinkelmessungen, Röntgen-Photoelektronenspektroskopie und Flugzeit-Sekundärionen-Massenspektrometrie und einer Zellanhaftung-Assay wird auch beschrieben.

Polymer Microarrays für High Throughput Discovery of Biomaterials

The discovery of novel biomaterials that are optimized for a specific biological application is readily achieved using polymer microarrays, which allows a ...

polymer-microarrays-for-high-throughput-discovery-of-biomaterials

Research

JoVE Journal

Bioengineering

14.4K Aufrufe.  University of Nottingham. Eine Beschreibung der Bildung eines Polymers unter Verwendung eines Mikroarray-on-Chip-Technik Photopolymerisation. Der hohe Durchsatz Oberflächencharakterisierung mittels Rasterkraftmikroskopie, Wasser Randwinkelmessungen, Röntgen-Photoelektronenspektroskopie und Flugzeit-Sekundärionen-Massenspektrometrie und einer Zellanhaftung-Assay wird auch beschrieben.

Serie: Polymer Microarrays for High Throughput Discovery of Biomaterials

Candida albicans Biofilm Chip (CaBChip) for High-throughput Antifungal Drug Screening

Candida albicans remains the main etiological agent of candidiasis, which currently represents the fourth most common nosocomial bloodstream infection in US hospitals1. These opportunistic infections pose a growing threat for an increasing number of compromised individuals, and carry unacceptably high mortality rates. This is in part due to the limited arsenal of antifungal drugs, but also to the emergence of resistance against the most commonly used antifungal agents. Further complicating treatment is the fact that a majority of manifestations of candidiasis are associated with the formation of biofilms, and cells within these biofilms show increased levels of resistance to most clinically-used antifungal agents2. Here we describe the development of a high-density microarray that consists of C. albicans nano-biofilms, which we have named CaBChip3. Briefly, a robotic microarrayer is used to print yeast cells of C. albicans onto a solid substrate. During printing, the yeast cells are enclosed in a three dimensional matrix using a volume as low as 50 nL and immobilized on a glass substrate with a suitable coating. After initial printing, the slides are incubated at 37 &deg;C for 24 hours to allow for biofilm development. During this period the spots grow into fully developed "nano-biofilms" that display typical structural and phenotypic characteristics associated with mature C. albicans biofilms (i.e. morphological complexity, three dimensional architecture and drug resistance)4. Overall, the CaBChip is composed of ~750 equivalent and spatially distinct biofilms; with the additional advantage that multiple chips can be printed and processed simultaneously. Cell viability is estimated by measuring the fluorescent intensity of FUN1 metabolic stain using a microarray scanner. This fungal chip is ideally suited for use in true high-throughput screening for antifungal drug discovery. Compared to current standards (i.e. the 96-well microtiter plate model of biofilm formation5), the main advantages of the fungal biofilm chip are automation, miniaturization, savings in amount and cost of reagents and analyses time, as well as the elimination of labor intensive steps. We believe that such chip will significantly speed up the antifungal drug discovery process.

Candida albicans Biofilm Chip CaBChip for High-throughput Antifungal Drug Screening

We have developed a high-density microarray platform consisting of 3D nano-biofilms of C. albicans called CaBChip. The susceptibility profile of drugs tested on a CaBChip is comparable to the conventional 96-well plate model, suggesting that the fungal chip is ideally suited for true high-throughput screening of antifungal drugs.

Candida albicans Biofilm Chip (Ca BChip) für das Hochdurchsatz-Screening-Antimykotikum

Candida  albicans remains the main etiological agent of candidiasis, which  currently represents the fourth most common nosocomial bloodstream infection ...

Forschung

Biotechnik

Combinatorial Synthesis of and High-throughput Protein Release from Polymer Film and Nanoparticle Libraries

Polyanhydrides are a class of biomaterials with excellent biocompatibility and drug delivery capabilities. While they have been studied extensively with conventional one-sample-at-a-time synthesis techniques, a more recent high-throughput approach has been developed enabling the synthesis and testing of large libraries of polyanhydrides1. This will facilitate more efficient optimization and design process of these biomaterials for drug and vaccine delivery applications. The method in this work describes the combinatorial synthesis of biodegradable polyanhydride film and nanoparticle libraries and the high-throughput detection of protein release from these libraries. In this robotically operated method (Figure 1), linear actuators and syringe pumps are controlled by LabVIEW, which enables a hands-free automated protocol, eliminating user error. Furthermore, this method enables the rapid fabrication of micro-scale polymer libraries, reducing the batch size while resulting in the creation of multivariant polymer systems. This combinatorial approach to polymer synthesis facilitates the synthesis of up to 15 different polymers in an equivalent amount of time it would take to synthesize one polymer conventionally. In addition, the combinatorial polymer library can be fabricated into blank or protein-loaded geometries including films or nanoparticles upon dissolution of the polymer library in a solvent and precipitation into a non-solvent (for nanoparticles) or by vacuum drying (for films). Upon loading a fluorochrome-conjugated protein into the polymer libraries, protein release kinetics can be assessed at high-throughput using a fluorescence-based detection method (Figures 2 and 3) as described previously1. This combinatorial platform has been validated with conventional methods2 and the polyanhydride film and nanoparticle libraries have been characterized with 1H NMR and FTIR. The libraries have been screened for protein release kinetics, stability and antigenicity; in vitro cellular toxicity, cytokine production, surface marker expression, adhesion, proliferation and differentiation; and in vivo biodistribution and mucoadhesion1-11. The combinatorial method developed herein enables high-throughput polymer synthesis and fabrication of protein-loaded nanoparticle and film libraries, which can, in turn, be screened in vitro and in vivo for optimization of biomaterial performance.

This method describes the combinatorial synthesis of biodegradable polyanhydride film and nanoparticle libraries and the high-throughput detection of protein release from these libraries.

Kombinatorische Synthese von und High-Throughput-Protein Release von Polymer Film-und Nanopartikel-Bibliotheken

Polyanhydrides are a class of biomaterials with excellent biocompatibility and drug delivery capabilities. While they have been studied extensively with ...

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

Hochdurchsatz-Synthese von Kohlenhydraten und Funktionalisierung von Nanopartikeln Polyanhydrid

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

Evaluation of Biomaterials for Bladder Augmentation using Cystometric Analyses in Various Rodent Models

Renal function and continence of urine are critically dependent on the proper function of the urinary bladder, which stores urine at low pressure and expels it with a precisely orchestrated contraction. A number of congenital and acquired urological anomalies including posterior urethral valves, benign prostatic hyperplasia, and neurogenic bladder secondary to spina bifida/spinal cord injury can result in pathologic tissue remodeling leading to impaired compliance and reduced capacity1. Functional or anatomical obstruction of the urinary tract is frequently associated with these conditions, and can lead to urinary incontinence and kidney damage from increased storage and voiding pressures2. Surgical implantation of gastrointestinal segments to expand organ capacity and reduce intravesical pressures represents the primary surgical treatment option for these disorders when medical management fails3. However, this approach is hampered by the limitation of available donor tissue, and is associated with significant complications including chronic urinary tract infection, metabolic perturbation, urinary stone formation, and secondary malignancy4,5.
Current research in bladder tissue engineering is heavily focused on identifying biomaterial configurations which can support regeneration of tissues at defect sites. Conventional 3-D scaffolds derived from natural and synthetic polymers such as small intestinal submucosa and poly-glycolic acid have shown some short-term success in supporting urothelial and smooth muscle regeneration as well as facilitating increased organ storage capacity in both animal models and in the clinic6,7. However, deficiencies in scaffold mechanical integrity and biocompatibility often result in deleterious fibrosis8, graft contracture9, and calcification10, thus increasing the risk of implant failure and need for secondary surgical procedures. In addition, restoration of normal voiding characteristics utilizing standard biomaterial constructs for augmentation cystoplasty has yet to be achieved, and therefore research and development of novel matrices which can fulfill this role is needed.
In order to successfully develop and evaluate optimal biomaterials for clinical bladder augmentation, efficacy research must first be performed in standardized animal models using detailed surgical methods and functional outcome assessments. We have previously reported the use of a bladder augmentation model in mice to determine the potential of silk fibroin-based scaffolds to mediate tissue regeneration and functional voiding characteristics.11,12 Cystometric analyses of this model have shown that variations in structural and mechanical implant properties can influence the resulting urodynamic features of the tissue engineered bladders11,12. Positive correlations between the degree of matrix-mediated tissue regeneration determined histologically and functional compliance and capacity evaluated by cystometry were demonstrated in this model11,12. These results therefore suggest that functional evaluations of biomaterial configurations in rodent bladder augmentation systems may be a useful format for assessing scaffold properties and establishing in vivo feasibility prior to large animal studies and clinical deployment. In the current study, we will present various surgical stages of bladder augmentation in both mice and rats using silk scaffolds and demonstrate techniques for awake and anesthetized cystometry.

Surgical stages of bladder augmentation are described using 3-D scaffolds in murine and rat models. To test the efficacy of biomaterial configurations for use in bladder augmentation, techniques for both awake and anesthetized cystometry are presented.

Bewertung von Biomaterialien für Blasenvergrößerung mit Zystometrische Analysen in verschiedenen Tiermodellen

Renal function and continence of urine are critically dependent on the proper function of the urinary bladder, which stores urine at low pressure and ...

A Full Skin Defect Model to Evaluate Vascularization of Biomaterials In Vivo

Insufficient vascularization is considered to be one of the main factors limiting the clinical success of tissue-engineered constructs. In order to evaluate new strategies that aim at improving vascularization, reliable methods are required to make the in-growth of new blood vessels into bio-artificial scaffolds visible and quantify the results. Over the past couple of years, our group has introduced a full skin defect model that enables the direct visualization of blood vessels by transillumination and provides the possibility of quantification through digital segmentation. In this model, one surgically creates full skin defects in the back of mice and replaces them with the material tested. Molecules or cells of interest can also be incorporated in such materials to study their potential effect. After an observation time of one&#8217;s own choice, materials are explanted for evaluation. Bilateral wounds provide the possibility of making internal comparisons that minimize artifacts among individuals as well as of decreasing the number of animals needed for the study. In comparison to other approaches, our method offers a simple, reliable and cost effective analysis. We have implemented this model as a routine tool to perform high-resolution screening when testing vascularization of different biomaterials and bio-activation approaches.

A Full Skin Defect Model to Evaluate Vascularization of Biomaterials In Vivo

Vascularization is key to approaches in successful tissue engineering. Therefore, reliable technologies are required to evaluate the development of vascular networks in tissue-constructs. Here we present a simple and cost-effective method to visualize and quantify vascularization in vivo.

Ein Vollhautdefekt Modell zur Vaskularisierung von Biomaterialien Bewerten<em&gt; In Vivo</em

Insufficient vascularization is considered to be one of the main factors limiting the clinical success of tissue-engineered constructs. In order to ...

A Coupled Experiment-finite Element Modeling Methodology for Assessing High Strain Rate Mechanical Response of Soft Biomaterials

This study offers a combined experimental and finite element (FE) simulation approach for examining the mechanical behavior of soft biomaterials (e.g. brain, liver, tendon, fat, etc.) when exposed to high strain rates. This study utilized a Split-Hopkinson Pressure Bar (SHPB) to generate strain rates of 100-1,500 sec-1. The SHPB employed a striker bar consisting of a viscoelastic material (polycarbonate). A sample of the biomaterial was obtained shortly postmortem and prepared for SHPB testing. The specimen was interposed between the incident and transmitted bars, and the pneumatic components of the SHPB were activated to drive the striker bar toward the incident bar. The resulting impact generated a compressive stress wave (i.e. incident wave) that traveled through the incident bar. When the compressive stress wave reached the end of the incident bar, a portion continued forward through the sample and transmitted bar (i.e. transmitted wave) while another portion reversed through the incident bar as a tensile wave (i.e. reflected wave). These waves were measured using strain gages mounted on the incident and transmitted bars. The true stress-strain behavior of the sample was determined from equations based on wave propagation and dynamic force equilibrium. The experimental stress-strain response was three dimensional in nature because the specimen bulged. As such, the hydrostatic stress (first invariant) was used to generate the stress-strain response. In order to extract the uniaxial (one-dimensional) mechanical response of the tissue, an iterative coupled optimization was performed using experimental results and Finite Element Analysis (FEA), which contained an Internal State Variable (ISV) material model used for the tissue. The ISV material model used in the FE simulations of the experimental setup was iteratively calibrated (i.e. optimized) to the experimental data such that the experiment and FEA strain gage values and first invariant of stresses were in good agreement.

The current study prescribes a coupled experiment-finite element simulation methodology to obtain the uniaxial dynamic mechanical response of soft biomaterials (brain, liver, tendon, fat, etc.). The multiaxial experimental results that arose because of specimen bulging obtained from Split-Hopkinson Pressure Bar testing were rendered to a uniaxial true stress-strain behavior when simulated through iterative optimization of the finite element analysis of the biomaterial.

A Gekoppelt Experiment-Finite-Elemente-Modeling-Methode zur Bewertung Hohe Strain Rate Mechanisches Verhalten von weicher Biomaterialien

This study offers a combined experimental and finite element (FE) simulation approach for examining the mechanical behavior of soft biomaterials (e.g. ...

Sandwich-like Microenvironments to Harness Cell/Material Interactions

Cell culture has been traditionally carried out on bi-dimensional (2D) substrates where cells adhere using ventral receptors to the biomaterial surface. However in vivo, most of the cells are completely surrounded by the extracellular matrix (ECM), resulting in a three-dimensional (3D) distribution of receptors. This may trigger differences in the outside-in signaling pathways and thus in cell behavior.
This article shows that stimulating the dorsal receptors of cells already adhered to a 2D substrate by overlaying a film of a new material (a sandwich-like culture) triggers important changes with respect to standard 2D cultures. Furthermore, the simultaneous excitation of ventral and dorsal receptors shifts cell behavior closer to that found in 3D environments. Additionally, due to the nature of the system, a sandwich-like culture is a versatile tool that allows the study of different parameters in cell/material interactions, e.g., topography, stiffness and different protein coatings at both the ventral and dorsal sides. Finally, since sandwich-like cultures are based on 2D substrates, several analysis procedures already developed for standard 2D cultures can be used normally, overcoming more complex procedures needed for 3D systems.

The following protocol describes the procedure to assemble sandwich-like cultures to be used as an intermediate stage between bi-dimensional (2D) and three-dimensional (3D) cellular environments. The engineered systems can have applications in microscopy, biomechanics, biochemistry and cell biology assays.

Sandwichartigen Mikroumgebungen zu nutzen Handy / Material-Interaktionen

Cell culture has been traditionally carried out on bi-dimensional (2D) substrates where cells adhere using ventral receptors to the biomaterial surface. ...

Using Tomoauto: A Protocol for High-throughput Automated Cryo-electron Tomography

Cryo-electron tomography (Cryo-ET) is a powerful three-dimensional (3-D) imaging technique for visualizing macromolecular complexes in their native context at a molecular level. The technique involves initially preserving the sample in its native state by rapidly freezing the specimen in vitreous ice, then collecting a series of micrographs from different angles at high magnification, and finally computationally reconstructing a 3-D density map. The frozen-hydrated specimen is extremely sensitive to the electron beam and so micrographs are collected at very low electron doses to limit the radiation damage. As a result, the raw cryo-tomogram has a very low signal to noise ratio characterized by an intrinsically noisy image. To better visualize subjects of interest, conventional imaging analysis and sub-tomogram averaging in which sub-tomograms of the subject are extracted from the initial tomogram and aligned and averaged are utilized to improve both contrast and resolution. Large datasets of tilt-series are essential to understanding and resolving the complexes at different states, conditions, or mutations as well as obtaining a large enough collection of sub-tomograms for averaging and classification. Collecting and processing this data can be a major obstacle preventing further analysis. Here we describe a high-throughput cryo-ET protocol based on a computer-controlled 300kV cryo-electron microscope, a direct detection device (DDD) camera and a highly effective, semi-automated image-processing pipeline software wrapper library tomoauto developed in-house. This protocol has been effectively utilized to visualize the intact type III secretion system (T3SS) in Shigella flexneri minicells. It can be applicable to any project suitable for cryo-ET.

We present a protocol on how to utilize high-throughput cryo-electron tomography to determine high resolution in situ structures of molecular machines. The protocol permits large amounts of data to be processed, avoids common bottlenecks and reduces resource downtime, allowing the user to focus on important biological questions.

Verwendung Tomoauto: Ein Protokoll für die Hochdurchsatz-Automated Kryo-Elektronentomographie

Cryo-electron tomography (Cryo-ET) is a powerful three-dimensional (3-D) imaging technique for visualizing macromolecular complexes in their native ...

A Microfluidic Platform for High-throughput Single-cell Isolation and Culture

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet high-throughput, method to perform single-cell culture experiments. Here, we report a microfluidic chip-based strategy for high-efficiency single-cell isolation (~77%) and demonstrate its capability of performing long-term single-cell culture (up to 7 d) and cellular heterogeneity analysis using clonogenic assay. These applications were demonstrated with KT98 mouse neural stem cells, and A549 and MDA-MB-435 human cancer cells. High single-cell isolation efficiency and long-term culture capability are achieved by using different sizes of microwells on the top and bottom of the microfluidic channel. The small microwell array is designed for precisely isolating single-cells, and the large microwell array is used for single-cell clonal culture in the microfluidic chip. This microfluidic platform constitutes an attractive approach for single-cell culture applications, due to its flexibility of adjustable cell culture spaces for different culture strategies, without decreasing isolation efficiency.

Here, we present a protocol for isolating and culturing single cells with a microfluidic platform, which utilizes a new microwell design concept to allow for high-efficiency single cell isolation and long-term clonal culture.

Ein Mikrofluidik-Plattform für Hochdurchsatz-Einzelzell-Isolierung und Kultur

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet ...

High-throughput Identification of Bacteria Repellent Polymers for Medical Devices

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as contributing to antimicrobial resistance. One possible avenue for the reduction of device-associated infections is the identification of bacteria-repellent polymer coatings for these devices, which would prevent bacterial binding at the initial attachment step. A method for the identification of such repellent polymers, based on the parallel screening of hundreds of polymers using a microarray, is described here. This high-throughput method resulted in the identification of a range of promising polymers that resisted binding of various clinically relevant bacterial species individually and also as multi-species communities. One polymer, PA13 (poly(methylmethacrylate-co-dimethylacrylamide)), demonstrated significant reduction in attachment of a number of hospital isolates when coated onto two commercially available central venous catheters. The method described could be applied to identify polymers for a wide range of applications in which modification of bacterial attachment is important.

A high-throughput microarray method for the identification of polymers which reduce bacterial surface binding on medical devices is described.

Hochdurchsatz-Identifizierung von Bakterien abstoßenden Polymere für medizinische Geräte

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as ...