Questa ricerca è stata in parte sostenuta dalla National Science Foundation (NSF 1.227.359), WVU programma EPSCoR finanziato dalla National Science Foundation (EPS-1.003.907), ufficio ADVANCE WVU sponsorizzato dalla National Science Foundation (1.007.978), e WVU PSCoR, rispettivamente. Il lavoro è stato fatto in microfabrication WVU condivise Istituti di ricerca (attrezzature per camere bianche) e microfluidica Integrative di ricerca cellulare sul Laboratorio Chip (microchip Lab) della West Virginia University. Il confocale è stato fatto a WVU Microscopio Imaging strumento.

1. Fotolitografia Fabbricazione di Photoresist Maestro Mold Il seguente protocollo mostra il processo per fabbricare i microcanali con diametri tra 30-60 micron. Per ottenere un microcanali con un diametro più piccolo (meno di 30 um), un singolo spin-coating di photoresist è necessario. <ol><li> Trasferire il photoresist reflow dal frigorifero a 4 ° C per la camera sterile 24 ore prima dell&#39;uso e lasciarla a temperatura ambiente. </li><li> Pulire un wafer di silicio e cuocere per un ora a 150 ° C per lasciarlo disidratare. La disidratazione assisterà il photoresist adesione al substrato di silicio. </li><li> Spin-coat il primo strato di fotoresist usando la seguente ricetta: </li></ol><table border="1"><tbody><tr><td> Passo </td><td> Tempo (secondi) </td><td> Velocità (rpm) </td><td> Accelerazione </td></tr><tr><td> 1 </td><td> 2 &lt;/ Td&gt; <td> 300 </td><td> più alto </td></tr><tr><td> 2 </td><td> 10 </td><td> 0 </td><td></td></tr><tr><td> 3 </td><td> 3 </td><td> 300 </td><td> più alto </td></tr><tr><td> 4 </td><td> 60 </td><td> 600 </td><td> più alto </td></tr><tr><td> 5 </td><td> 10 </td><td> 500 </td><td> più alto </td></tr><tr><td> 6 </td><td> 10 </td><td> 600 </td><td> più alto </td></tr></tbody></table><ol start="4"><li> Poi, cuocere il wafer su una piastra con una temperatura di 110 ° C per 90 sec. Dopo la cottura morbida lo spessore del fotoresist sarà 20-30 micron. </li><li> Spin cappotto un secondo strato di fotoresist con la stessa formulazione utilizzata per il primo strato. </li><li> Morbido cuocere nuovamente il wafer ponendolo su una piastra con una temperatura di 110 ° C per 90 sec. Dopo questa cuocere morbido lo spessore del fotoresist sarà 40-60 micron. </li><li> Generare i modelli maestri positivi esponendo il PhotoRESIST a luce UV con una dose di esposizione di 14.500 mJ / cm 2 attraverso una maschera pellicola. </li><li> Diluire la sviluppatore con deionizzata (DI) (1:2 (v / v)). Risciacquare il wafer ripetutamente nella soluzione fino a quando il modello è completamente sviluppato. Quindi lavare il wafer con acqua deionizzata e asciugare con gas azoto. </li><li> Reflow: Posizionare il wafer su una piastra con una temperatura di 120 ° C per 4 min e coprire con un piatto di vetro Petri per evitare l&#39;evaporazione del solvente. Togliere la cialda dalla piastra e lasciarla raffreddare a temperatura ambiente. Lo spessore fotoresist dopo la rifusione sarà 50-60 micron. </li></ol> 2. Morbido litografia Fabbricazione di PDMS Microchannel Network <ol><li> Preparare polydimethylsiloxane soluzione (PDMS) al rapporto di peso di 10:1 (base: catalizzatore) e mescolare accuratamente con un mescolatore planetario centrifuga. </li><li> Gettate la soluzione PDMS sullo stampo maestro photoresist ridisposto. Posizionare il PDMS colato in un essiccatore per 15 minuti a Degas. Usare il gas azoto per eliminare eventuali bolle rimanenti se necessario. </li><li> Cuocere la PDMS in forno ad una temperatura di 60 ° C per 3 ore per permettere a polimerizzare. Quindi rimuovere lo strato di PDMS curata dallo stampo master. </li><li> Usare un perforatore affilato per creare fori di ingresso / uscita da buchi nella rete di canali di punzonatura. Pulire la superficie del PDMS con gas azoto. </li><li> Trattare due strati PDMS con plasma di ossigeno per 30 secondi all&#39;interno di un pulitore plasma ad una pressione di 4,5 x 10 -2 Torr e un flusso di ossigeno di 3,5 m 3 / min. Poi, allineare le superfici del PDMS manualmente al microscopio ottico. Utilizzare una goccia d&#39;acqua, se necessario per un migliore controllo dell&#39;allineamento. </li><li> Cuocere il dispositivo in un forno a 60 ° C per 30 minuti per ottenere l&#39;unione permanente. </li></ol> 3. Cultura HUVEC e semina nel chip <ol><li> Cultura delle HUVEC con terreno di coltura con la L-glutamina supplementato con 10% siero fetale bovino (FBS). Per Thsono stati utilizzati posta esperimento passaggi tra 2 e 5. </li><li> Una volta che le HUVEC sono confluenti, contare le cellule e raccoglierle dalle prime risciacquo le cellule con soluzione salina tamponata con HEPES (HEPES-BSS), e poi trattare le cellule con tripsina / EDTA e incubare per 2-6 minuti a 37 ° C. Dopo la tripsinizzazione è completa, neutralizzare la tripsina / EDTA soluzione neutralizzante con tripsina. Centrifugare e sospendere le cellule nel terreno di coltura con l&#39;8% di destrano per raccoglierli. Destrano è stato usato per aumentare la media viscosità per facilitare una migliore semina cellulare e attaccamento. </li><li> Trattare il dispositivo con plasma di ossigeno per 5 minuti con una pressione di 4,5 x 10 -2 Torr e un flusso di ossigeno di 3,5 m 3 / min. Quindi caricare il dispositivo con acqua deionizzata e trattare con la luce UV per 8 ore in un biosicurezza cappa laminare per la sterilizzazione. </li><li> Un giorno prima che le cellule sono pronte, lavare l&#39;apparecchio con 1x tampone fosfato (PBS 1x) poi cappotto con fibronectina (100 mg / ml, dilbuite con 1x PBS) e incubare in frigorifero a 4 ° C durante la notte. </li><li> Dopo il rivestimento fibronectina, lavare il dispositivo con PBS 1x quindi caricare con mezzo di coltura. Incubare il dispositivo a una temperatura di 37 ° C per 15 min. </li><li> Caricare le cellule HUVEC in 8% destrano mezzo di coltura con una concentrazione cellulare di 3-4 x 10 6 cellule / ml. Posizionare una gocciolina 20 microlitri di cellule ad un ingresso del dispositivo e inclinarlo introdurre le cellule nel canale microfluidica. Dopo 15-20 minuti le cellule cominceranno ad attribuire alle pareti laterali dei canali. Ruotare il dispositivo ogni 15 min per creare una distribuzione più uniforme delle cellule. Se necessario, un carico addizionale può essere eseguita. </li></ol> 4. Setup perfusione a lungo termine Dopo 5-6 ore di cultura statica, i HUVECs allegate inizieranno a diffondersi completamente fuori. Impostare perfusione utilizzando un sistema di pompa a siringa con telecomando e un flusso costante di 10 ml / h. Perfusione può essere regolato fo una portata maggiore, e può durare per un periodo di tempo compreso tra 4 giorni a 2 settimane. 5. Cella di colorazione e del microscopio Caratterizzazione <ol><li> Quando le cellule raggiungono confluenza all&#39;interno del dispositivo, in primo luogo, lavare il dispositivo con 1x PBS per rimuovere completamente il mezzo. Quindi caricare il dispositivo con colorante rosso diluito con diluente (4 microlitri-1 ml). Caricare il colorante simile alla procedura di caricamento delle cellule. Incubare il dispositivo al buio per 5 minuti a temperatura ambiente, e poi lavare il dispositivo con terreno di coltura per fermare la colorazione. Lunga incubazione del colorante può causare tossicità cellulare e disadhesion. </li><li> Caricare il dispositivo con il colorante blu diluito con PBS 1x (2 gocce per ml). Incubare al buio per 5 minuti a temperatura ambiente, poi lavare accuratamente il dispositivo con PBS 1x. </li><li> Esaminare la colorazione delle cellule al microscopio ottico invertito. Se la colorazione è stata buona, caricare i microcanali con il mezzo di fissaggio (3,5% paraformaldeide diluito con PBS 1x), quindi immergereil dispositivo di fissaggio a medio e coprire completamente con foglio di alluminio. Conservare il dispositivo in frigorifero a una temperatura di 4 ° C per evitare che il dispositivo si secchi e photobleaching. Il dispositivo fisso è ora pronto per l&#39;imaging confocale, che può essere fatto da un microscopio confocale a scansione laser. </li></ol>

Gli autori dichiarano di non avere interessi finanziari in competizione.

<html> 1. Muffa fabbricazione Maestro Uno dei principi di progettazione e di guida per morfometria vascolare è nota come legge di Murray 16, in cui si afferma che la distribuzione dei diametri dei vasi in tutta la rete è governata da corrispettivo minimo di energia. Si precisa inoltre che il cubo dei diametri di un vaso parente ad una biforcazione uguale alla somma dei cubi dei diametri dei vasi figlia ( <img alt="Equazione 1" fo:content-width="0.9in" fo:src="/files/ftp_upload/50771...

Microvasi, come parte del sistema di circolazione, mediare le interazioni tra sangue e tessuti, sostenere attività metaboliche, definire microambiente tissutale, e gioca un ruolo critico in molte condizioni patologiche e salute. Ricapitolazione dei microvasi funzionali in vitro potrebbe fornire una piattaforma per lo studio dei fenomeni vascolari complesse. Tuttavia, convenzionale in vitro microvasi saggi, come il test di migrazione delle cellule endoteliali, saggi di formazione endoteliali tubo, e di ratto e topo saggi anello aortico, sono in grado di ricreare in vivo microvasi rispetto a tre dimensioni (3D) geometria e il controllo di flusso continuo 1-8. Studi di microvasi utilizzando modelli animali e in vivo, come il saggio di angiogenesi corneale, pulcino corioallantoidea membrana saggio angiogenesi, e il dosaggio spina Matrigel, sono di più in termini di tempo, ad alto costo, sfidando rispetto alla osservazione e quantificazioni, esollevare questioni etiche 1, 9-13. I progressi nella micromanufacturing e tecnologie nell&#39;ambito dei chip microfluidici hanno permesso una serie di intuizioni in scienze biomediche, mentre limitare gli alti costi sperimentali e le complessità associati con gli animali e in vivo studi 14, come le condizioni biologiche controllate facilmente e saldamente e ambienti fluidi dinamici, che non avrebbero stato possibile con tecniche convenzionali macroscala. Qui vi presentiamo un metodo per costruire un endothelialized microcanali-on-a-chip che imita la geometria 3D in vivo microvasi e gira sotto flusso di perfusione continua controllato utilizzando la combinazione di tecnica fotolitografica reflowable photoresist, litografia soft, e microfluidica.

<table border="1">
	<tbody>
		<tr>
			<td>Reagent/Material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reflow Photoresist</td>
			<td>AZ Electronic Materials</td>
			<td>AZP4620</td>
			<td></td>
		</tr>
		<tr>
			<td>Developer</td>
			<td>AZ Electronic Materials</td>
			<td>AZ 400K</td>
			<td></td>
		</tr>
		<tr>
			<td>PDMS</td>
			<td>Dow Corning Corporation</td>
			<td>Sylgard 184</td>
			<td></td>
		</tr>
		<tr>
			<td>MCDB 131 Culture Medium</td>
			<td>Invitrogen</td>
			<td>10372-019</td>
			<td></td>
		</tr>
		<tr>
			<td>NacBlue Nuclei Staining</td>
			<td>Invitrogen</td>
			<td>H1399</td>
			<td></td>
		</tr>
		<tr>
			<td>PKH Red Stain</td>
			<td>Sigma</td>
			<td>MINI26 and PKH26GL</td>
			<td></td>
		</tr>
		<tr>
			<td>Fibronectin</td>
			<td>Gibco</td>
			<td>PHE0023</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>Sigma</td>
			<td>G7513</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline</td>
			<td>Invitrogen</td>
			<td>14040-133</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES Buffered Saline Solution</td>
			<td>Lonza</td>
			<td>CC-5024</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin/EDTA</td>
			<td>Invitrogen</td>
			<td>25300-062</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin Neutralizing Solution</td>
			<td>Lonza</td>
			<td>CC-5002</td>
			<td></td>
		</tr>
		<tr>
			<td>PDMS Curing Agent</td>
			<td>Dow Corning Corporation</td>
			<td>Sylgard 184</td>
			<td></td>
		</tr>
		<tr>
			<td>Primary Human Umbilical Vein Endothelial Cells</td>
			<td>Lonza</td>
			<td>CC-2517</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Lonza</td>
			<td>14-501F</td>
			<td></td>
		</tr>
		<tr>
			<td>Diluent C</td>
			<td>Sigma</td>
			<td>CGLDIL</td>
			<td></td>
		</tr>
		<tr>
			<td>Hoechst33342</td>
			<td>Invitrogen, Molecular Probes</td>
			<td>R37605</td>
			<td></td>
		</tr>
		<tr>
			<td>Dextran</td>
			<td>Sigma</td>
			<td>95771</td>
			<td></td>
		</tr>
		<tr>
			<td>3.5% Paraformaldehyde</td>
			<td>Electron Microscopy Science</td>
			<td>15710-S</td>
			<td></td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Spinner</td>
			<td>Laurell Technologies Corporation</td>
			<td>WS-400BZ-6NPP/LITE</td>
			<td></td>
		</tr>
		<tr>
			<td>Desiccator</td>
			<td>BelArt Products</td>
			<td>999320237</td>
			<td></td>
		</tr>
		<tr>
			<td>Inverted Microscope</td>
			<td>Nikon</td>
			<td>Eclipse Ti</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe Pump System</td>
			<td>Harvard Apparatus</td>
			<td>PHD Ultra</td>
			<td></td>
		</tr>
		<tr>
			<td>Laminar Biosafety Hood</td>
			<td>Thermo Scientific</td>
			<td>1300 Series A2</td>
			<td></td>
		</tr>
		<tr>
			<td>Planetary Centrifugal Mixer</td>
			<td>Thinky</td>
			<td>ARE-310</td>
			<td></td>
		</tr>
		<tr>
			<td>Isotemp Oven</td>
			<td>Fisher Scientific</td>
			<td>13-246-516GAQ</td>
			<td></td>
		</tr>
		<tr>
			<td>Optical Microscope</td>
			<td>Zeiss</td>
			<td>Invertoskop 40C</td>
			<td></td>
		</tr>
		<tr>
			<td>Plasma Cleaner</td>
			<td>Harrick Plasma</td>
			<td>PDC-32G</td>
			<td></td>
		</tr>
		<tr>
			<td>Hotplate</td>
			<td>Barnstead/Thermolyne Cimarec</td>
			<td>SP131635</td>
			<td></td>
		</tr>
		<tr>
			<td>Laser Scanning Confocal Microscope</td>
			<td>Zeiss</td>
			<td>LSM 510</td>
			<td></td>
		</tr>
	</tbody>
</table>

procedure for the development of multi-depth circular cross-sectional endothelialized microchannels-on-a-chip

Gli sforzi si sono concentrati sullo sviluppo di test in vitro per lo studio dei microvasi, perché in vivo sugli animali sono più in termini di tempo, costosa, e l&#39;osservazione e quantificazione sono molto impegnativo. Tuttavia, convenzionale in microvasi saggi in vitro hanno dei limiti quando rappresentano in vivo microvasi rispetto alla geometria tridimensionale (3D) e di fornire il flusso del fluido continuo. Usando una combinazione di tecnica fotolitografica reflowable photoresist, litografia soft, e microfluidica, abbiamo sviluppato un multi-profondità endothelialized trasversali circolari microcanali-on-a-chip, che imita la geometria 3D in vivo microvasi e gira sotto perfusione continua controllata flusso. Un fotoresist positivo reflowable stato usato per fabbricare uno stampo matrice con una rete di microcanali sezione trasversale semicircolare. Dall&#39;allineamento e incollaggio dei due polidimetilsilossano (PDMS) microcanali replicated dallo stampo maestro, è stata creata una rete di microcanali cilindrica. I diametri dei microcanali possono essere ben controllate. Inoltre, le cellule endoteliali della vena ombelicale umana (HUVEC primarie) seminate all&#39;interno del chip hanno mostrato che le cellule allineate la superficie interna dei microcanali sotto perfusione controllata duraturo per un periodo di tempo compreso tra 4 giorni a 2 settimane.

Il nostro approccio per fabbricare la rete di microcanali multi-profondità imita le complesse geometrie 3D di microvasi in vivo, in cui i microcanali sono arrotondate sezioni trasversali 15. Inoltre, i diametri dei canali di ramificazione madri ei canali figlia circa obbediscono legge di Murray per mantenere il flusso di fluido ad un livello desiderato in modo che la resistenza complessiva del canale è bassa e velocità di flusso sono più uniforme in tutta la rete 16-18. I processi e ri...

Watch this Scientific Journal Video about Procedure for the Development of Multi-depth Circular Cross-sectional Endothelialized Microchannels-on-a-chip at JoVE.com

Procedure for the Development of Multi-depth Circular Cross-sectional Endothelialized Microchannels-on-a-chip

Una piattaforma microcanali-on-a-chip è stato sviluppato dalla combinazione di tecnica fotolitografica reflowable photoresist, litografia soft, e microfluidica. La piattaforma microcanali endothelialized imita il tridimensionale (3D) geometria in vivo microvasi, corre sotto flusso perfusione continua controllato, permette l&#39;imaging di alta qualità e in tempo reale e può essere applicato per la ricerca microvascolare.

Procedura per lo sviluppo di multi-profondità circolare a sezione trasversale Endothelialized microcanali-on-a-chip

Efforts have been focused on developing in vitro assays for the study of microvessels because in vivo animal studies are more time-consuming, expensive, ...

procedure-for-development-multi-depth-circular-cross-sectional

Research

JoVE Journal

Bioengineering

13.8K Views.  West Virginia University.  Una piattaforma microcanali-on-a-chip è stato sviluppato dalla combinazione di tecnica fotolitografica reflowable photoresist, litografia soft, e microfluidica. La piattaforma microcanali endothelialized imita il tridimensionale (3D) geometria in vivo microvasi, corre sotto flusso perfusione continua controllato, permette l'imaging di alta qualità e in tempo reale e può essere applicato per la ricerca microvascolare. 

Video: Procedure for the Development of Multi-depth Circular Cross-sectional Endothelialized Microchannels-on-a-chip

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.

Procedura per l&#39;Ingegneria del polmone

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

Ricerca

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 ...

Procedure for Decellularization of Porcine Heart by Retrograde Coronary Perfusion

Perfusion-based whole organ decellularization has recently gained interest in the field of tissue engineering as a means to create site-specific extracellular matrix scaffolds, while largely preserving the native architecture of the scaffold. To date, this approach has been utilized in a variety of organ systems, including the heart, lung, and liver 1-5. Previous decellularization methods for tissues without an easily accessible vascular network have relied upon prolonged exposure of tissue to solutions of detergents, acids, or enzymatic treatments as a means to remove the cellular and nuclear components from the surrounding extracellular environment6-8. However, the effectiveness of these methods hinged upon the ability of the solutions to permeate the tissue via diffusion. In contrast, perfusion of organs through the natural vascular system effectively reduced the diffusion distance and facilitated transport of decellularization agents into the tissue and cellular components out of the tissue. Herein, we describe a method to fully decellularize an intact porcine heart through coronary retrograde perfusion. The protocol yielded a fully decellularized cardiac extracellular matrix (c-ECM) scaffold with the three-dimensional structure of the heart intact. Our method used a series of enzymes, detergents, and acids coupled with hypertonic and hypotonic rinses to aid in the lysis and removal of cells. The protocol used a Trypsin solution to detach cells from the matrix followed by Triton X-100 and sodium deoxycholate solutions to aid in removal of cellular material. The described protocol also uses perfusion speeds of greater than 2 L/min for extended periods of time. The high flow rate, coupled with solution changes allowed transport of agents to the tissue without contamination of cellular debris and ensured effective rinsing of the tissue. The described method removed all nuclear material from native porcine cardiac tissue, creating a site-specific cardiac ECM scaffold that can be used for a variety of applications.

A method to rapidly and completely remove cellular components from an intact porcine heart through retrograde perfusion is described. This method yields a site specific cardiac extracellular matrix scaffold which has the potential for use in multiple clinical applications.

Procedura per decellularizzazione del Cuore di suino da retrograda perfusione coronarica

Perfusion-based  whole organ decellularization has recently gained interest in the field of  tissue engineering as a means to create site-specific ...

Methods for Characterizing the Co-development of Biofilm and Habitat Heterogeneity

Biofilms are surface-attached microbial communities that have complex structures and produce significant spatial heterogeneities. Biofilm development is strongly regulated by the surrounding flow and nutritional environment. Biofilm growth also increases the heterogeneity of the local microenvironment by generating complex flow fields and solute transport patterns. To investigate the development of heterogeneity in biofilms and interactions between biofilms and their local micro-habitat, we grew mono-species biofilms of Pseudomonas aeruginosa and dual-species biofilms of P. aeruginosa and Escherichia coli under nutritional gradients in a microfluidic flow cell. We provide detailed protocols for creating nutrient gradients within the flow cell and for growing and visualizing biofilm development under these conditions. We also present protocols for a series of optical methods to quantify spatial patterns in biofilm structure, flow distributions over biofilms, and mass transport around and within biofilm colonies. These methods support comprehensive investigations of the co-development of biofilm and habitat heterogeneity.

Biofilms have complex interactions with their surrounding environment. To comprehensively investigate biofilm-environment interactions, we present here a series of methods to create heterogeneous chemical environment for biofilm development, to quantify local flow velocity, and to analyze mass transport in and around biofilm colonies.

Metodi per caratterizzare il co-sviluppo di biofilm e Habitat Eterogeneità

Biofilms are surface-attached microbial communities that have complex structures and produce significant spatial heterogeneities. Biofilm development is ...

Solid Lipid Nanoparticles (SLNs) for Intracellular Targeting Applications

Nanoparticle-based delivery vehicles have shown great promise for intracellular targeting applications, providing a mechanism to specifically alter cellular signaling and gene expression. In a previous investigation, the synthesis of ultra-small solid lipid nanoparticles (SLNs) for topical drug delivery and biomarker detection applications was demonstrated. SLNs are a well-studied example of a nanoparticle delivery system that has emerged as a promising drug delivery vehicle. In this study, SLNs were loaded with a fluorescent dye and used as a model to investigate particle-cell interactions. The phase inversion temperature (PIT) method was used for the synthesis of ultra-small populations of biocompatible nanoparticles. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylphenyltetrazolium bromide (MTT) assay was utilized in order to establish appropriate dosing levels prior to the nanoparticle-cell interaction studies. Furthermore, primary human dermal fibroblasts and mouse dendritic cells were exposed to dye-loaded SLN over time and the interactions with respect to toxicity and particle uptake were characterized using fluorescence microscopy and flow cytometry. This study demonstrated that ultra-small SLNs, as a nanoparticle delivery system, are suitable for intracellular targeting of different cell types.

Solid Lipid Nanoparticles SLNs for Intracellular Targeting Applications

In this study, a method for synthesizing ultra-small populations of biocompatible nanoparticles was described, as well as several in vitro methods by which to assess their cellular interactions.

Solid Lipid nanoparticelle (linfonodi sentinella) Applicazioni per intracellulare targeting

Nanoparticle-based delivery vehicles have shown great promise for intracellular targeting applications, providing a mechanism to specifically alter ...

Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

A two-dimensional gas chromatography-time-of-flight mass spectrometry method is described for characterization of the aqueous fraction of bio-crude produced from hydrothermal liquefaction of algae. This protocol can also be employed to analyze the aqueous fraction of liquid products from fast pyrolysis, catalytic fast pyrolysis, catalytic deoxygenation and hydro-treating.

Caratterizzazione qualitativa della frazione acquosa da idrotermale Liquefazione di alghe Utilizzando 2D gascromatografia con tempo di volo spettrometria di massa

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in ...

Development of a Multicellular Three-dimensional Organotypic Model of the Human Intestinal Mucosa Grown Under Microgravity

Because cells growing in a three-dimensional (3-D) environment have the potential to bridge many gaps of cell cultivation in 2-D environments (e.g., flasks or dishes). In fact, it is widely recognized that cells grown in flasks or dishes tend to de-differentiate and lose specialized features of the tissues from which they were derived. Currently, there are mainly two types of 3-D culture systems where the cells are seeded into scaffolds mimicking the native extracellular matrix (ECM): (a) static models and (b) models using bioreactors. The first breakthrough was the static 3-D models. 3-D models using bioreactors such as the rotating-wall-vessel (RWV) bioreactors are a more recent development. The original concept of the RWV bioreactors was developed at NASA&#39;s Johnson Space Center in the early 1990s and is believed to overcome the limitations of static models such as the development of hypoxic, necrotic cores. The RWV bioreactors might circumvent this problem by providing fluid dynamics that allow the efficient diffusion of nutrients and oxygen. These bioreactors consist of a rotator base that serves to support and rotate two different formats of culture vessels that differ by their aeration source type: (1) Slow Turning Lateral Vessels (STLVs) with a co-axial oxygenator in the center, or (2) High Aspect Ratio Vessels (HARVs) with oxygenation via a flat, silicone rubber gas transfer membrane. These vessels allow efficient gas transfer while avoiding bubble formation and consequent turbulence. These conditions result in laminar flow and minimal shear force that models reduced gravity (microgravity) inside the culture vessel. Here we describe the development of a multicellular 3-D organotypic model of the human intestinal mucosa composed of an intestinal epithelial cell line and primary human lymphocytes, endothelial cells and fibroblasts cultured under microgravity provided by the RWV bioreactor.

Cells growing in a three-dimensional (3-D) environment represent a marked improvement over cell cultivation in 2-D environments (e.g., flasks or dishes). Here we describe the development of a multicellular 3-D organotypic model of the human intestinal mucosa cultured under microgravity provided by rotating-wall-vessel (RWV) bioreactors.

Sviluppo di un multicellulare tridimensionale Organotipica Modello della mucosa intestinale umana coltivate in microgravità

Because cells growing in a three-dimensional (3-D) environment have the potential to bridge many gaps of cell cultivation in 2-D environments (e.g., ...

Assembly and Tracking of Microbial Community Development within a Microwell Array Platform

The development of microbial communities depends on a combination of complex deterministic and stochastic factors that can dramatically alter the spatial distribution and activities of community members. We have developed a microwell array platform that can be used to rapidly assemble and track thousands of bacterial communities in parallel. This protocol highlights the utility of the platform and describes its use for optically monitoring the development of simple, two-member communities within an ensemble of arrays within the platform. This demonstration uses two mutants of Pseudomonas aeruginosa, part of a series of mutants developed to study Type VI secretion pathogenicity. Chromosomal inserts of either mCherry or GFP genes facilitate the constitutive expression of fluorescent proteins with distinct emission wavelengths that can be used to monitor community member abundance and location within each microwell. This protocol describes a detailed method for assembling mixtures of bacteria into the wells of the array and using time-lapse fluorescence imaging and quantitative image analysis to measure the relative growth of each member population over time. The seeding and assembly of the microwell platform, the imaging procedures necessary for the quantitative analysis of microbial communities within the array, and the methods that can be used to reveal interactions between microbial species area all discussed.

The development of microbial communities depends on a combination of factors, including environmental architecture, member abundance, traits, and interactions. This protocol describes a synthetic, microfabricated environment for the simultaneous tracking of thousands of communities contained in femtoliter wells, where key factors such as niche size and confinement can be approximated.

Assemblea e monitoraggio dello sviluppo microbico della comunità all&#39;interno di una piattaforma di array Microwell

The development of microbial communities depends on a combination of complex deterministic and stochastic factors that can dramatically alter the spatial ...

Standard Test Method ASTM D 7998-19 for the Cohesive Strength Development of Wood Adhesives

The properties of cured wood adhesives are difficult to study because of the loss of water and other components to the wood, the influence of wood on the adhesive cure, and the effect of adhesive penetration on the wood interphase; thus, normal testing of a neat adhesive film is generally not useful. Most tests of wood adhesive bond strength are slow, laborious, can be strongly influenced by the wood and do not provide information on the kinetics of cure. Test method ASTM D 7998-19, however, can be used for fast evaluation of the strength of wood bonds. The use of a smooth, uniform, and strong wood surface, like maple face-veneer, and sufficient bonding pressure reduces the adhesion and wood strength effects on bond strength. This method has three main applications. The first is to provide consistent data on bond strength development. The second is to measure the dry and wet strengths of bonded lap shear samples. The third is to better understand the adhesive heat resistance by quickly evaluating thermal sensitivity and distinguishing between thermal softening and thermal degradation.

We present a procedure, ASTM D7998-19, for a rapid and more consistent evaluation of both dry and wet strength of adhesive bonds on wood. The method can also be used to provide information on strength development as a function of temperature and time or strength retention up to 250 &#176;C.

Metodo di prova standard ASTM D 7998-19 per lo sviluppo della resistenza coesiva degli adesivi per legno

The properties of cured wood adhesives are difficult to study because of the loss of water and other components to the wood, the influence of wood on the ...

Asymmetrical Flow Field-Flow Fractionation for Sizing of Gold Nanoparticles in Suspension

Particle size is arguably the most important physico-chemical parameter associated with the notion of a nanoparticle. Precise knowledge of the size and size distribution of nanoparticles is of utmost importance for various applications. The size range is also important, as it defines the most &#8220;active&#8221; component of a nanoparticle dose.
Asymmetrical Flow Field-Flow Fractionation (AF4) is a powerful technique for sizing of particles in suspension in the size range of approximately 1&#8211;1000 nm. There are several ways to derive size information from an AF4 experiment. Besides coupling AF4 online with size-sensitive detectors based on the principles of Multi-Angle Light Scattering or Dynamic Light Scattering, there is also the possibility to correlate the size of a sample with its retention time using a well-established theoretical approach (FFF theory) or by comparing it with the retention times of well-defined particle size standards (external size calibration).
We here describe the development and in-house validation of a standard operating procedure (SOP) for sizing of an unknown gold nanoparticle sample by AF4 coupled with UV-vis detection using external size calibration with gold nanoparticle standards in the size range of 20&#8211;100 nm. This procedure provides a detailed description of the developed workflow including sample preparation, AF4 instrument setup and qualification, AF4 method development and fractionation of the unknown gold nanoparticle sample, as well as the correlation of the obtained results with the established external size calibration. The SOP described here was eventually successfully validated in the frame of an interlaboratory comparison study highlighting the excellent robustness and reliability of AF4 for sizing of nanoparticulate samples in suspension.

This protocol describes the use of Asymmetrical Flow Field-Flow Fractionation coupled with UV-vis detection for the determination of the size of an unknown gold nanoparticle sample.

Frazionamento asimmetrico del flusso campo-flusso per il dimensionamento delle nanoparticelle d'oro in sospensione

Particle size is arguably the most important physico-chemical parameter associated with the notion of a nanoparticle. Precise knowledge of the size and ...