La tecnologia SynVivo è stato sviluppato sotto concessione # 2R44HL076034 dal NHLBI.

1. Adescamento del dispositivo Microfluidic SynVivo-SMN <ol><li> Ogni porta (ingresso / uscita) del dispositivo comprende due porte parallele - una per fluire in frazioni rivestimento superficiale (molecole di adesione, matrici di crescita, ecc) e / o cellule di semina e l&#39;altro per eseguire il test (Figura 1A ). </li><li> Immergere completamente il dispositivo microfluidica SynVivo-SMN (Figura 1B) in una capsula di Petri contenente deionizzata sterile (DI) e posizionare il piatto in un essiccatore a vuoto. Lasciare l&#39;essiccatore di eseguire fino a quando tutta l&#39;aria viene rimosso dai canali del dispositivo. Questo dovrebbe durare circa 15 min. </li><li> Prima di rimuovere il dispositivo dal acqua, mettere il tubo Tygon (diametro di 0,06 &quot;e ID di 0,02&quot;) innescato con acqua in ogni porta del dispositivo con una pinza a punta fine. Il tubo deve essere di circa 1 pollice. Il dispositivo può essere rimosso dall&#39;acqua. Figura 1C mostra immagine della devicoE Con ​​il tubo. </li></ol> 2. Rivestimento del dispositivo Microfluidic con la proteina desiderata (ad esempio, Avidin) <ol><li> Usando una pipetta, una goccia di acqua (circa 100 ml) intorno alla base del tubo una porta di ingresso. Rimuovere con cautela il tubo utilizzato per innescare il dispositivo. La goccia d&#39;acqua impedisce all&#39;aria di entrare dispositivo. </li><li> Preparare una siringa da 1 ml caricato con avidina ad una concentrazione di 20 ug / ml. Collegare la siringa un ago in acciaio inossidabile 24 G e tubi. Inserire il tubo ad una delle porte di ingresso del dispositivo. Bloccare la porta di ingresso non essere utilizzato con un morsetto mascella. </li><li> Iniettare avidina ad un flusso di 1 ml / min per 10 min per permettere la completa perfusione del dispositivo. Alla fine del tempo di flusso, bloccare il tubo con il morsetto mascella e posizionare il dispositivo a 4 ° C per una notte. </li></ol> 3. Scorrere la Particelle Biotinylated per gli esperimenti di adesione <ol><li> Lasciare il dispositivoa temperatura ambiente. Posizionare il dispositivo su un microscopio invertito a fluorescenza equipaggiato con un tavolino motorizzato e una telecamera ad alte prestazioni. </li><li> Preparare una soluzione di 2 micron particelle biotinilati ad una concentrazione di 5 x 10 6 particelle / ml in tampone fosfato salino (PBS). Caricare le particelle in una siringa da 1 ml. Preparare una seconda siringa da 1 ml di PBS solo. Caricare ogni siringa su una pompa a siringa e connettersi ago e tubo. </li><li> Usando una pipetta, una goccia di acqua (circa 100 ml) intorno alla base del tubo di entrata. Rimuovere con cautela il tubo utilizzato per rivestire il dispositivo. La goccia d&#39;acqua impedisce all&#39;aria di entrare dispositivo. </li><li> Inserire con cautela il tubo di particelle biotinilati e PBS dal punto 3.2 in ciascuna delle porte di ingresso. Figura 2A mostra l&#39;immagine del set-up. </li><li> Inizia iniettando particelle biotinilati ad una portata di 2,5 ml / min. Monitorare la porta di ingresso sul microscopio. Al primo segnodi particelle, avviare il timer e continuare flusso per 3 min. </li><li> Alla fine del 3 min, fermare il flusso di particelle biotinilati contemporaneamente fissando il flusso di PBS ad una portata di 2,5 ml / min. Lasciare PBS di fluire nel dispositivo per 3 minuti per lavare via le particelle non legate. </li></ol> 4. Acquisizione di immagini e Fare area di interesse (AOI) Misure Utilizzo del software di imaging (NIKON Elements) <ol><li> Utilizzare la funzione &quot;immagine di scansione grande&quot; nel software di imaging per acquisire l&#39;immagine dell&#39;intero dispositivo. </li><li> Numero sequenziale le biforcazioni nel dispositivo e creare una AOI circolare con due volte il diametro dei canali. In questo caso, impostare il diametro AOI a 200 micron in quanto il diametro del canale è di 100 micron. </li><li> Utilizzare la funzione di conteggio automatico del software di imaging per esportare il numero di particelle in ogni AOI ad un foglio di MS Excel. </li><li> Analogamente, utilizzare la funzione di conteggio automatico di esportare il numero di particelle nell&#39;interadispositivo. </li></ol> 5. Particelle Flux Analisi Uso Computational Fluid Dynamics (CFD) Modelli <ol><li> Simulazioni CFD vengono eseguiti utilizzando il software disponibile in commercio (CFD-ACE +, ESI Inc.) per la topologia dispositivo SynVivo-SMN. I risultati sono memorizzati in un database per analizzare osservazioni sperimentali. I risultati della simulazione memorizzare le informazioni sui tassi di parete di taglio, velocità, flusso di particelle, e l&#39;adesione nel dispositivo. </li><li> I risultati della simulazione vengono utilizzati per determinare il numero di particelle che entrano ogni AOI basato su una determinata concentrazione di particelle in ingresso. </li></ol> 6. Generazione Shear adesione Map <ol><li> Calcolo della% di aderenza dividendo le particelle attaccate nella biforcazione dalle particelle che fluiscono nella biforcazione come mostrato nell&#39;equazione 6.1. <img alt="Equazione 1" fo:content-width="3in" src="/files/ftp_upload/51025/51025eq1.jpg" /> dove il numero di particelle e le particelle aderiscono scorre sono ottenuti da protocol i punti 4.3 e 5.2, rispettivamente. </li><li> Tracciare la mappa adesione shear utilizzando il gradiente di velocità ad ogni biforcazione delle reti ottenuti dal database nella fase (5.1) ed i valori di adesione% ottenuti dall&#39;equazione 6.1. </li></ol>

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Tassa di pubblicazione per questo articolo sponsorizzato da CFD Research Corporation.

Camere di flusso piastra paralleli, fornendo spunti significativi in ​​interazioni cellula-cellula e cellula-particelle, soffrono di alcune limitazioni quali elevato consumo di reagenti e la necessità di molteplici prove sperimentali di generare una mappa adesione taglio. L&#39;uso delle reti microvascolari SynVivo-sintetiche (SynVivo-SMNs) consente la generazione di una mappa di adesione al taglio da un singolo esperimento in condizioni che mimano le condizioni in vivo. Inoltre, si ottiene anche un rispar...

Saggi attuali studiare per cellula-cellula e cellula-interazioni delle particelle tipicamente comportano statica formato pozzetti in cui le particelle o le cellule vengono incubate su matrici proteiche o cellule aderenti. Al termine del tempo di incubazione specificato, il numero di particelle aderenti o cellule vengono quantificati mediante microscopia 1. Anche se questi test forniscono informazioni significative sui processi biochimici che stanno dietro queste interazioni, una limitazione fondamentale è la mancanza di flusso del fluido fisiologico (tipico del microcircolo) e il suo impatto sulla adesione delle particelle. Per superare questa limitazione, camere di flusso in vitro sono stati sviluppati negli ultimi anni. Un elemento comune di queste camere di flusso è un apparecchio trasparente perfusione a bassi numeri di Reynolds per abbinare i tassi di taglio della parete osservati nei vasi sanguigni in vivo 2. La parete del serbatoio è modellato da uno strato di biomolecole o crescita di cellule su una superficie del flusso cHamber 3. Particelle 4-7 o 8-16 cellule vengono poi scorreva dentro al campo desiderato di portate di quantificare il numero di aderire particelle sotto vari gradienti di velocità. Tuttavia, l&#39;utilizzo di camere di flusso piastra paralleli per studiare e validare i fenomeni biochimici è piuttosto costoso e richiede tempo. Ciò è dovuto principalmente al fatto che esperimenti multipli devono essere realizzati per generare una mappa della fluidico taglio rispetto al numero di particelle / cellule aderito. Inoltre, camere di flusso piastra richiedono grandi volumi di reagenti causa delle loro grandi dimensioni (altezza&gt; 250 micron e larghezza&gt; 1 mm). Infine, questi dispositivi non modellare accuratamente caratteristiche geometriche (ad esempio, biforcazioni) e condizioni di flusso (ad esempio, convergenti vs divergenti flussi) che sono presenti in vivo. I recenti progressi nella litografia basata microfabbricazione 17-19 hanno accelerato il campo di lab-on-a-chipdispositivi di 20-21. Questi dispositivi hanno contribuito a sviluppare una versione miniaturizzata della camera di flusso a piatti paralleli con dimensioni in regime micrometro. La riduzione di dimensione produce anche vantaggi significativi in ​​termini di volumi di reagenti, cellule o particelle richiesta per esperimenti. Tuttavia, una limitazione chiave dei dispositivi attualmente disponibili è l&#39;uso di canali lineari per modellare microvasi, che non imitano il complesso microcircolo osservato in vivo. Abbiamo recentemente sviluppato una nuova metodologia per ricreare le reti microvascolari su substrati di plastica usa e getta con conseguente rappresentazione sintetica delle condizioni in vivo. Questi dispositivi chiamati reti microvascolari SynVivo-sintetiche (SMN), sono sviluppate utilizzando PDMS basate processo soft-litografia. Dispositivi SynVivo-SMN possono essere utilizzati per ottenere shear mappa adesione di cellule / particella adesione 22, studio mirato consegna della droga 23 e have stato validato con i dati in vivo 24-25. In questo articolo, vi presentiamo un protocollo che consente la generazione della mappa di adesione al taglio da un singolo esperimento in volumi piccoli come 1-5 microlitri un conseguente notevole risparmio di risorse e di tempo.

<table border="0" cellpadding="0" cellspacing="0" width="638">
	<tbody>
		<tr>
			<td>SynVivo-SMN</td>
			<td>CFD Research</td>
			<td>SMN-001</td>
			<td>Exclusive at CFDRC</td>
		</tr>
		<tr>
			<td>CFD-ACE+</td>
			<td>ESI Inc.</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Avidin</td>
			<td>Invitrogen</td>
			<td>43-4401</td>
			<td>Any avidin source will work for this assay</td>
		</tr>
		<tr>
			<td>Biotinylated Particles</td>
			<td>Polysciences</td>
			<td>24173-1</td>
			<td>Any source of biotinylated particles will work for the assay</td>
		</tr>
		<tr>
			<td>Tygon Tubing</td>
			<td>VWR</td>
			<td>63018-044</td>
			<td>Size is typical for use with SynVivo-SMN</td>
		</tr>
		<tr>
			<td>NIKON Elements</td>
			<td>NIKON Instruments</td>
			<td>N/A</td>
			<td>Any other imaging software can be used</td>
		</tr>
	</tbody>
</table>

generation of shear adhesion map using synvivo synthetic microvascular networks

Saggi di adesione cellulare / particelle sono fondamentali per comprendere le interazioni biochimiche coinvolte nella patofisiologia della malattia e avere importanti applicazioni nella ricerca per lo sviluppo di nuove terapie. I saggi che utilizzano condizioni statiche riescono a catturare la dipendenza di adesione su taglio, limitando la loro correlazione con l&#39;ambiente in vivo. Camere di flusso piastra paralleli che quantificano l&#39;adesione sotto il flusso del fluido fisiologico bisogno di più esperimenti per la generazione di una mappa adesione taglio. Inoltre, essi non rappresentano la scala in vivo e morfologia e richiedono grandi volumi (~ ml) di reagenti per esperimenti. In questo studio, abbiamo dimostrato la generazione di taglio mappa adesione da un singolo esperimento utilizzando una rete microvascolare basata dispositivo microfluidica, SynVivo-SMN. Questo dispositivo ricrea il complesso sistema vascolare vivo tra cui scala geometrica, elementi morfologici, le caratteristiche dei flussi e le interazioni cellulari in unformato in vitro, fornendo in tal modo un ambiente biologicamente realistico per ricerca di base e applicata nel comportamento cellulare, la consegna della droga, e la scoperta della droga. Il saggio è stato dimostrato studiando l&#39;interazione dei 2 micron particelle biotina-avidina rivestite con superfici rivestite del microchip. L&#39;intera gamma di taglio osservata nel microcircolo è ottenuta in un singolo saggio consenta adesione vs shear mappa per le particelle in condizioni fisiologiche.

La figura 1A mostra una immagine schematica campo chiaro e di dispositivo SynVivo-SMN. Figura 1B mostra il dispositivo SynVivo-SMN montato su un vetrino. Figura 1C mostra il dispositivo con la tubazione seguente priming con acqua in un essiccatore sotto vuoto. Figura 2A mostra un&#39;immagine della sperimentale-impostato. Figura 2B mostra un tipico dispositivo SynVivo-SMN avidina rivestite conseguente al leg...

Watch this Scientific Journal Video about Generation of Shear Adhesion Map Using SynVivo Synthetic Microvascular Networks at JoVE.com

Generation of Shear Adhesion Map Using SynVivo Synthetic Microvascular Networks

Flow chambers used in adhesion experiments typically consist of linear flow paths and require multiple experiments at different flow rates to generate a shear adhesion map. SynVivo-SMN enables the generation of shear adhesion map using a single experiment utilizing microliter volumes resulting in significant savings in time and consumables.

Generazione di Shear Adesione mappa usando SynVivo reti microvascolari sintetico

Cell/particle adhesion assays are critical to understanding the biochemical interactions involved in disease pathophysiology and have important ...

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Bioengineering

8.8K Views.  CFD Research Corporation. Flow chambers used in adhesion experiments typically consist of linear flow paths and require multiple experiments at different flow rates to generate a shear adhesion map. SynVivo-SMN enables the generation of shear adhesion map using a single experiment utilizing microliter volumes resulting in significant savings in time and consumables. 

Video: Generation of Shear Adhesion Map Using SynVivo Synthetic Microvascular Networks

Plasma Lithography Surface Patterning for Creation of Cell Networks

Systematic manipulation of a cell microenvironment with micro- and nanoscale resolution is often required for deciphering various cellular and molecular phenomena. To address this requirement, we have developed a plasma lithography technique to manipulate the cellular microenvironment by creating a patterned surface with feature sizes ranging from 100 nm to millimeters. The goal of this technique is to be able to study, in a controlled way, the behaviors of individual cells as well as groups of cells and their interactions.
This plasma lithography method is based on selective modification of the surface chemistry on a substrate by means of shielding the contact of low-temperature plasma with a physical mold. This selective shielding leaves a chemical pattern which can guide cell attachment and movement. This pattern, or surface template, can then be used to create networks of cells whose structure can mimic that found in nature and produces a controllable environment for experimental investigations. The technique is well suited to studying biological phenomenon as it produces stable surface patterns on transparent polymeric substrates in a biocompatible manner. The surface patterns last for weeks to months and can thus guide interaction with cells for long time periods which facilitates the study of long-term cellular processes, such as differentiation and adaption. The modification to the surface is primarily chemical in nature and thus does not introduce topographical or physical interference for interpretation of results. It also does not involve any harsh or toxic substances to achieve patterning and is compatible for tissue culture. Furthermore, it can be applied to modify various types of polymeric substrates, which due to the ability to tune their properties are ideal for and are widely used in biological applications. The resolution achievable is also beneficial, as isolation of specific processes such as migration, adhesion, or binding allows for discrete, clear observations at the single to multicell level.
This method has been employed to form diverse networks of different cell types for investigations involving migration, signaling, tissue formation, and the behavior and interactions of neurons arraigned in a network.

A versatile plasma lithography technique has been developed to generate stable surface patterns for guiding cellular attachment. This technique can be applied to create cell networks including those that mimic natural tissues and has been used for studying several, distinct cell types.

Plasma Surface Patterning litografia per la creazione di reti di cella

Systematic manipulation of a cell microenvironment with micro- and nanoscale resolution is often required for deciphering various cellular and molecular ...

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Bioingegneria

Endothelialized Microfluidics for Studying Microvascular Interactions in Hematologic Diseases

Advances in microfabrication techniques have enabled the production of inexpensive and reproducible microfluidic systems for conducting biological and biochemical experiments at the micro- and nanoscales 1,2. In addition, microfluidics have also been specifically used to quantitatively analyze hematologic and microvascular processes, because of their ability to easily control the dynamic fluidic environment and biological conditions3-6. As such, researchers have more recently used microfluidic systems to study blood cell deformability, blood cell aggregation, microvascular blood flow, and blood cell-endothelial cell interactions6-13.However, these microfluidic systems either did not include cultured endothelial cells or were larger than the sizescale relevant to microvascular pathologic processes. A microfluidic platform with cultured endothelial cells that accurately recapitulates the cellular, physical, and hemodynamic environment of the microcirculation is needed to further our understanding of the underlying biophysical pathophysiology of hematologic diseases that involve the microvasculature.
Here, we report a method to create an "endothelialized" in vitro model of the microvasculature, using a simple, single mask microfabrication process in conjunction with standard endothelial cell culture techniques, to study pathologic biophysical microvascular interactions that occur in hematologic disease. This "microvasculature-on-a-chip" provides the researcher with a robust assay that tightly controls biological as well as biophysical conditions and is operated using a standard syringe pump and brightfield/fluorescence microscopy. Parameters such as microcirculatory hemodynamic conditions, endothelial cell type, blood cell type(s) and concentration(s), drug/inhibitory concentration etc., can all be easily controlled. As such, our microsystem provides a method to quantitatively investigate disease processes in which microvascular flow is impaired due to alterations in cell adhesion, aggregation, and deformability, a capability unavailable with existing assays.

A method to culture an endothelial cell monolayer throughout the entire inner 3D surface of a microfluidic device with microvascular-sized channels (&lt;30 &mu;m) is described. This in vitro microvasculature model enables the study of biophysical interactions between blood cells, endothelial cells, and soluble factors in hematologic diseases.

Microfluidica Endothelialized per lo studio delle interazioni microvascolari nelle patologie ematologiche

Advances in  microfabrication techniques have enabled the production of inexpensive and  reproducible microfluidic systems for conducting biological and ...

Induction of Adhesion-dependent Signals Using Low-intensity Ultrasound

In multicellular organisms, cell behavior is dictated by interactions with the extracellular matrix. Consequences of matrix-engagement range from regulation of cell migration and proliferation, to secretion and even differentiation. The signals underlying each of these complex processes arise from the molecular interactions of extracellular matrix receptors on the surface of the cell. Integrins are the prototypic receptors and provide a mechanical link between extracellular matrix and the cytoskeleton, as well as initiating some of the adhesion-dependent signaling cascades. However, it is becoming increasingly apparent that additional transmembrane receptors function alongside the integrins to regulate both the integrin itself and signals downstream. The most elegant of these examples is the transmembrane proteoglycan, syndecan-4, which cooperates with &alpha;5&beta;1-integrin during adhesion to fibronectin. In vivo models demonstrate the importance of syndecan-4 signaling, as syndecan-4-knockout mice exhibit healing retardation due to inefficient fibroblast migration1,2. In wild-type animals, migration of fibroblasts toward a wound is triggered by the appearance of fibronectin that leaks from damaged capillaries and is deposited by macrophages in injured tissue. Therefore there is great interest in discovering strategies that enhance fibronectin-dependent signaling and could accelerate repair processes.
The integrin-mediated and syndecan-4-mediated components of fibronectin-dependent signaling can be separated by stimulating cells with recombinant fibronectin fragments. Although integrin engagement is essential for cell adhesion, certain fibronectin-dependent signals are regulated by syndecan-4. Syndecan-4 activates the Rac1 protrusive signal3, causes integrin redistribution1, triggers recruitment of cytoskeletal molecules, such as vinculin, to focal adhesions4, and thereby induces directional migration3. We have looked for alternative strategies for activating such signals and found that low-intensity pulsed ultrasound (LIPUS) can mimic the effects of syndecan-4 engagement5. In this protocol we describe the method by which 30 mW/cm2, 1.5 MHz ultrasound, pulsed at 1 kHz (Fig. 1) can be applied to fibroblasts in culture (Fig. 2) to induce Rac1 activation and focal adhesion formation. Ultrasound stimulation is applied for a maximum of 20 minutes, as this combination of parameters has been found to be most efficacious for acceleration of clinical fracture repair6. The method uses recombinant fibronectin fragments to engage &alpha;5&beta;1-integrin, without engagement of syndecan-4, and requires inhibition of protein synthesis by cycloheximide to block deposition of additional matrix by the fibroblasts., The positive effect of ultrasound on repair mechanisms is well documented7,8, and by understanding the molecular effect of ultrasound in culture we should be able to refine the therapeutic technique to improve clinical outcomes.

This protocol describes the stimulation of cultured fibroblasts with low-intensity pulsed ultrasound, which drives focal adhesion formation and Rac1 activation by mimicking engagement of the transmembrane matrix receptor, syndecan-4. This approach allows investigation of a successful clinical technique at the cellular level, thereby providing opportunities for refinement of the therapy.

L&#39;induzione di segnali di adesione-dipendenti utilizzando ultrasuoni a bassa intensità

In multicellular organisms, cell behavior is dictated by interactions with the extracellular matrix. Consequences of matrix-engagement range from ...

Using Cell-substrate Impedance and Live Cell Imaging to Measure Real-time Changes in Cellular Adhesion and De-adhesion Induced by Matrix Modification

Cell-matrix adhesion plays a key role in controlling cell morphology and signaling. Stimuli that disrupt cell-matrix adhesion (e.g., myeloperoxidase and other matrix-modifying oxidants/enzymes released during inflammation) are implicated in triggering pathological changes in cellular function, phenotype and viability in a number of diseases. Here, we describe how cell-substrate impedance and live cell imaging approaches can be readily employed to accurately quantify real-time changes in cell adhesion and de-adhesion induced by matrix modification (using endothelial cells and myeloperoxidase as a pathophysiological matrix-modifying stimulus) with high temporal resolution and in a non-invasive manner. The xCELLigence cell-substrate impedance system continuously quantifies the area of cell-matrix adhesion by measuring the electrical impedance at the cell-substrate interface in cells grown on gold microelectrode arrays. Image analysis of time-lapse differential interference contrast movies quantifies changes in the projected area of individual cells over time, representing changes in the area of cell-matrix contact. Both techniques accurately quantify rapid changes to cellular adhesion and de-adhesion processes. Cell-substrate impedance on microelectrode biosensor arrays provides a platform for robust, high-throughput measurements. Live cell imaging analyses provide additional detail regarding the nature and dynamics of the morphological changes quantified by cell-substrate impedance measurements. These complementary approaches provide valuable new insights into how myeloperoxidase-catalyzed oxidative modification of subcellular extracellular matrix components triggers rapid changes in cell adhesion, morphology and signaling in endothelial cells. These approaches are also applicable for studying cellular adhesion dynamics in response to other matrix-modifying stimuli and in related adherent cells (e.g., epithelial cells).

Here, we present a protocol to continuously quantify cell adhesion and de-adhesion processes with high temporal resolution in a non-invasive manner by cell-substrate impedance and live cell imaging analyses. These approaches reveal the dynamics of cell adhesion/de-adhesion processes triggered by matrix modification and their temporal relationship to adhesion-dependent signaling events.

Utilizzando impedenza Cell-substrato e imaging cellulare dal vivo per misurare i cambiamenti in tempo reale in Cellular Adesione e De-adesione indotta da Matrix Modifica

Cell-matrix adhesion plays a key role in controlling cell morphology and signaling. Stimuli that disrupt cell-matrix adhesion (e.g., myeloperoxidase and ...

Using Synthetic Biology to Engineer Living Cells That Interface with Programmable Materials

We have developed an abiotic-biotic interface that allows engineered cells to control the material properties of a functionalized surface. This system is made by creating two modules: a synthetically engineered strain of E. coli cells and a functionalized material interface. Within this paper, we detail a protocol for genetically engineering selected behaviors within a strain of E. coli using molecular cloning strategies. Once developed, this strain produces elevated levels of biotin when exposed to a chemical inducer. Additionally, we detail protocols for creating two different functionalized surfaces, each of which is able to respond to cell-synthesized biotin. Taken together, we present a methodology for creating a linked, abiotic-biotic system that allows engineered cells to control material composition and assembly on nonliving substrates.

This paper presents a series of protocols for developing engineered cells and functionalized surfaces that enable synthetically engineered E. coli to control and manipulate programmable material surfaces.

Utilizzando biologia sintetica per Ingegnere cellule viventi che si interfacciano con materiali programmabili

We have developed an abiotic-biotic interface that allows engineered cells to control the material properties of a functionalized surface. This system is ...

Gene Expression Analysis of Endothelial Cells Exposed to Shear Stress Using Multiple Parallel-plate Flow Chambers

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate flow chambers. Endothelial cells form the inner cellular lining of blood vessels and are chronically exposed to the frictional force of blood flow called shear stress. Under physiological conditions, endothelial cells function in the presence of various shear stress conditions. Thus, the application of shear stress conditions in in vitro models can provide greater insight into endothelial responses in vivo. The parallel-plate flow chamber previously published by Lane et al.9 is adapted to study endothelial gene regulation in the presence and absence of steady (non-pulsatile) laminar flow. Key adaptations in the set-up for laminar flow as presented here include a large, dedicated environment to house concurrent flow circuits, the monitoring of flow rates in real-time, and the inclusion of an exogenous reference RNA for the normalization of quantitative real-time PCR data. To assess multiple treatments/conditions with the application of shear stress, multiple flow circuits and pumps are used simultaneously within the same heated and humidified incubator. The flow rate of each flow circuit is measured continuously in real-time to standardize shear stress conditions throughout the experiments. Because these experiments have multiple conditions, we also use an exogenous reference RNA that is spiked-in at the time of RNA extraction for the normalization of RNA extraction and first-strand cDNA synthesis efficiencies. These steps minimize the variability between samples. This strategy is employed in our pipeline for the gene expression analysis with shear stress experiments using the parallel-plate flow chamber, but parts of this strategy, such as the exogenous reference RNA spike-in, can easily and cost-effectively be used for other applications.

Here, a workflow for the culture and gene expression analysis of endothelial cells under fluid shear stress is presented. Included is a physical arrangement for simultaneously housing and monitoring multiple flow chambers in a controlled environment and the use of an exogenous reference RNA for quantitative PCR.

Analisi dell'espressione genica di cellule endoteliali esposte per Shear Stress utilizzando più flusso parallelo-piastra Chambers

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate ...

Live Cell Analysis of Shear Stress on Pseudomonas aeruginosa Using an Automated Higher-Throughput Microfluidic System

A higher-throughput microfluidic in vitro bioreactor coupled with fluorescence microscopy has been used to study bacterial biofilm growth and morphology, including Pseudomonas aeruginosa (P. aeruginosa). Here, we will describe how the system can be used to study the growth kinetics and the morphological properties such as the surface roughness and textural entropy of P. aeruginosa strain PA01 that expresses an enhanced green fluorescent protein (PA01-EGFP). A detailed protocol will describe how to grow and seed PA01-EGFP cultures, how to set up the microscope and autorun, and conduct the image analysis to determine growth rate and morphological properties using a variety of shear forces that are controlled by the microfluidic device. This article will provide a detailed description of a technique to improve the study of PA01-EGFP biofilms which eventually can be applied towards other strains of bacteria, fungi, or algae biofilms using the microfluidic platform.

Live Cell Analysis of Shear Stress on Pseudomonas aeruginosa Using an Automated Higher-Throughput Microfluidic System

Here, we describe the use of a higher-throughput microfluidic bioreactor coupled with a fluorescent microscope for the analysis of shear stress effects on Pseudomonas aeruginosa biofilms expressing green fluorescent proteins, including instrument set up, the determination of biofilm coverage, growth rate, and morphological properties.

Live Cell analisi della sollecitazione di taglio su Pseudomonas aeruginosa utilizzando un sistema di microfluidica superiore-Throughput automatizzato

A higher-throughput microfluidic in vitro bioreactor coupled with fluorescence microscopy has been used to study bacterial biofilm growth and morphology, ...

Generation of Transgenic Rats using a Lentiviral Vector Approach

Transgenic animal models are fundamentally important for modern biomedical research. The incorporation of foreign genes into early mouse or rat embryos is an invaluable tool for gene function analysis in living organisms. The standard transgenesis method is based on microinjecting foreign DNA fragments into a pronucleus of a fertilized oocyte. This technique is widely used in mice but remains relatively inefficient and technically demanding in other animal species. The transgene can also be introduced into one-cell-stage embryos via lentiviral infection, providing an effective alternative to standard pronuclear injections, especially in species or strains with a more challenging embryo structure. In this approach, a suspension that contains lentiviral vectors is injected into the perivitelline space of a fertilized rat embryo, which is technically less demanding and has a higher success rate. Lentiviral vectors were shown to efficiently incorporate the transgene into the genome to determine the generation of stable transgenic lines. Despite some limitations (e.g., Biosafety Level 2 requirements, DNA fragment size limits), lentiviral transgenesis is a rapid and efficient transgenesis method. Additionally, using female rats that are mated with a fertile male strain with a different dominant fur color is presented as an alternative to generate pseudopregnant foster mothers.

This article aims to provide the methodology for lentiviral transgenesis in rat embryos using multiple injections of a virus suspension into the zygote perivitelline space. Female rats that are mated with a fertile male strain with a different dominant fur color is used to generate pseudopregnant foster mothers.

Generazione di ratti transgenici con un approccio al vettore lentivirale

Transgenic animal models are fundamentally important for modern biomedical research. The incorporation of foreign genes into early mouse or rat embryos is ...

Preparing Protein Producing Synthetic Cells using Cell Free Bacterial Extracts, Liposomes and Emulsion Transfer

The bottom-up assembly approach for construction of synthetic cells is an effective tool for isolating and investigating cellular processes in a cell mimicking environment. Furthermore, the development of cell-free expression systems has demonstrated the ability to reconstitute the protein production, transcription and translation processes (DNA&#8594;RNA&#8594;protein) in a controlled manner, harnessing synthetic biology. Here we describe a protocol for preparing a cell-free expression system, including the production of a potent bacterial lysate and encapsulating this lysate inside cholesterol-rich lipid-based giant unilamellar vesicles (GUVs) (i.e., stable liposomes), to form synthetic cells. The protocol describes the methods for preparing the components of the synthetic cells including the production of active bacterial lysates, followed by a detailed step-by-step preparation of the synthetic cells based on a water-in-oil emulsion transfer method. These facilitate the production of millions of synthetic cells in a simple and affordable manner with a high versatility for producing different types of proteins. The obtained synthetic cells can be used to investigate protein/RNA production and activity in an isolated environment, in directed evolution, and also as a controlled drug delivery platform for on-demand production of therapeutic proteins inside the body.

This protocol describes the method, materials, equipment and steps for bottom-up preparation of RNA and protein producing synthetic cells. The inner aqueous compartment of the synthetic cells contained the S30 bacterial lysate encapsulated within a lipid bilayer (i.e., stable liposomes), using a water-in-oil emulsion transfer method.

Preparazione di proteine che producono cellule sintetiche utilizzando estratti batterici cell free, liposomi e trasferimento di emulsione

The bottom-up assembly approach for construction of synthetic cells is an effective tool for isolating and investigating cellular processes in a cell ...

Fabricating Multi-Component Lipid Nanotube Networks Using the Gliding Kinesin Motility Assay

Lipid nanotube (LNT) networks represent an in vitro model system for studying molecular transport and lipid biophysics with relevance to the ubiquitous lipid tubules found in eukaryotic cells. However, in vivo LNTs are highly non-equilibrium structures that require chemical energy and molecular motors to be assembled, maintained, and reorganized. Furthermore, the composition of in vivo LNTs is complex, comprising of multiple different lipid species. Typical methods to extrude LNTs are both time- and labor-intensive, and they require optical tweezers, microbeads, and micropipettes to forcibly pull nanotubes from giant lipid vesicles. Presented here is a protocol for the gliding motility assay (GMA), in which large scale LNT networks are rapidly generated from giant unilamellar vesicles (GUVs) using kinesin-powered microtubule motility. Using this method, LNT networks are formed from a wide array of lipid formulations that mimic the complexity of biological LNTs, making them increasingly useful for in vitro studies of lipid biophysics and membrane-associated transport. Additionally, this method is capable of reliably producing LNT networks in a short time (&#60;30 min) using commonly used laboratory equipment. LNT network characteristics such as length, width, and lipid partitioning are also tunable by altering the lipid composition of the GUVs used for fabricating the networks.

This protocol describes a process for fabricating lipid nanotube networks using gliding kinesin motility in conjunction with giant unilamellar lipid vesicles.

Fabbricazione di reti di nanotubi lipidici multicomponenti utilizzando il test di motilità di Kinesin gliding

Lipid nanotube (LNT) networks represent an in vitro model system for studying molecular transport and lipid biophysics with relevance to the ubiquitous ...