Bu araştırma kısmen Ulusal Bilim Vakfı (NSF 1.227.359), sırasıyla Ulusal Bilim Vakfı (EPS-1.003.907), Ulusal Bilim Vakfı (1.007.978) tarafından desteklenen WVU ADVANCE ofis ve WVU PSCoR tarafından finanse WVU EPSCoR programı, tarafından desteklenmiştir. Mikroimalat iş WVU Ortak Araştırma Olanakları (Temiz oda tesisleri) ve Batı Virginia Üniversitesi Chip Laboratuvarı (mikroçip Lab) üzerinde mikroakışkan Bütünleştirici Hücresel Araştırma yapıldı. Konfokal görüntüleme WVU Mikroskop Görüntüleme Tesisleri&#39;nde yapıldı.

1. Fotorezist Usta Kalıp Fotolitografi Fabrikasyon Aşağıdaki protokol, 30-60 mikron arasında çaplara sahip mikro imal etmek için işlemleri gösterir. Daha küçük bir çapı (en az 30 mikron), çeliğin tek bir spin kaplama olan bir mikrokanal elde etmek için gereklidir. <ol><li> Kullanmadan önce temiz oda, 24 saat için 4 ° C sıcaklıkta buzdolabında gelen yeniden akış fotorezist aktarın ve bu sırada oda sıcaklığına ısınmasına izin verir. </li><li> Bir silikon yonga temiz ve kurutmak için izin vermek için 150 ° C de bir saat boyunca pişirin. Dehidrasyon silikon substrat için ışığa yapışma yardımcı olacaktır. </li><li> Spin-kat fotorezist ilk katman aşağıdaki tarifi kullanarak: </li></ol><table border="1"><tbody><tr><td> Adım </td><td> Zaman (Saniye) </td><td> Hız (rpm) </td><td> Hızlanma </td></tr><tr><td> 1 </td><td> 2 &lt;/ Td&gt; <td> 300 </td><td> en yüksek </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> en yüksek </td></tr><tr><td> 4 </td><td> 60 </td><td> 600 </td><td> en yüksek </td></tr><tr><td> 5 </td><td> 10 </td><td> 500 </td><td> en yüksek </td></tr><tr><td> 6 </td><td> 10 </td><td> 600 </td><td> en yüksek </td></tr></tbody></table><ol start="4"><li> Daha sonra, 90 saniye boyunca 110 ° C arasında bir sıcaklığa sahip bir ocak gofret fırında. Yumuşak fırında sonra ışığa kalınlığı 20-30 mikron olacaktır. </li><li> Kat ilk kat için kullanılan aynı tarifi takip ışığa bir ikinci kat Spin. </li><li> Yumuşak fırında 90 saniye 110 ° C lik bir sıcaklık ile bir ocak üzerine yerleştirerek tekrar gofret. Bu yumuşak fırında sonra ışığa kalınlığı 40-60 mikron olacaktır. </li><li> PhotoR açarak olumlu ana desenleri oluşturmakbir film maske ile 14.500 mJ / cm 2 bir maruz kalma doz UV ışığına esist. </li><li> Deiyonize (Dİ) su (01:02 (v / v)) ile geliştirici seyreltin. Desen tam gelişmiş kadar çözümünde tekrar tekrar gofret durulayın. Daha sonra DI su ile gofret yıkayın ve azot gazı kullanarak kurulayın. </li><li> Reflow: 4 dakika ve solvent buharlaşmasını önlemek için bir cam Petri kabı ile kapak için 120 ° C lik bir sıcaklık ile bir ocak yeri gofret. Ocak gelen gofret çıkarın ve oda sıcaklığına kadar soğumasını bekleyin. Reflow sonra ışığa kalınlığı 50-60 mikron olacaktır. </li></ol> 2. PDMS Mikrokanal Ağ Yumuşak Litografi Fabrikasyon <ol><li> 10:1 ağırlık oranı (baz: sertleştirici) de polidimetilsiloksan (PDMS) çözeltisi hazırlayın ve bir gezegen santrifüj mikser kullanarak iyice karıştırın. </li><li> Yeniden akıtılan çeliğin ana kalıp üzerine PDMS çözüm Cast. Gazdan arındırmak için 15 dakika boyunca bir desikatör içinde döküm PDMS yerleştirin. Gerekirse kalan kabarcıklarını çıkarmak için azot gazı kullanın. </li><li> Bunun tedavisi için izin vermek için, 3 saat boyunca 60 ° C arasında bir sıcaklıkta bir fırında PDMS pişirilir. Daha sonra ana kalıp tedavi PDMS katmanı kaldırmak. </li><li> Kanal ağı delik delme tarafından giriş / çıkış delikleri oluşturmak için bilenmiş zımba kullanın. Azot gazı kullanarak PDMS yüzeyini temizlemek. </li><li> 4,5 x 10 -2 Torr ve 3,5 m 3 / dk oksijen akış hızı bir çalışma basıncında bir plazma temizleyici içinde 30 saniye oksijen plazma ile iki PDMS katmanları davranın. Daha sonra, bir optik mikroskop altında elle PDMS yüzeyleri hizalayın. Bir damla su hizalama daha iyi bir kontrolü için gerekli kullanın. </li><li> 60 ° C de sürekli yapışma elde etmek için 30 dakika boyunca bir fırında pişirmeye cihaz. </li></ol> 3. Chip içinde HUVEC Kültür ve Yayımlama <ol><li> Kültür L-glutamin ile kültür ortamı ile HUVEC&#39;ler,% 10 fetal sığır serumu (FBS) ile desteklenmiş. Th2 ile 5 arasında e deney pasajlar kullanılmıştır. </li><li> HUVEC&#39;lere birleşik bir kez, 37 ° C de 2-6 dakika hücreleri saymak ve ilk HEPES (HEPES-BSS) serum fizyolojik tamponlu ile hücreleri durulama bunları hasat ve sonra tripsin / EDTA ve inkübe ile hücrelerin tedavi Tripsinizasyon tamamlandıktan sonra, Tripsin çözeltisi ile nötralize tripsin / EDTA ile etkisiz hale getirir. Santrifüj ve toplamak için 8% dekstran ile kültür ortamı içinde hücre askıya. Dekstran iyi hücre tohumlama ve ek yardımcı olması için orta viskositesini artırmak için kullanılmıştır. </li><li> 5 4,5 x 10 -2 Torr bir çalışma basıncı ile dakika ve 3.5 bir oksijen akış hızı ft 3 / dk oksijen plazma cihazı tedavi. Daha sonra DI su ile cihaz yük ve sterilizasyon için bir laminer biyogüvenlik kaput 8 saat UV ışığı ile tedavi. </li><li> Hücrelerin hazır bir gün önce, 1x fosfat ile cihaz yıkayın fibronektin (100 mg / ml, dil ile kat sonra (1x PBS) tamponlu salin1X PBS ile uted) ve 4 ° C&#39;de bir gece boyunca buzdolabında inkübe edin. </li><li> Fibronektin kaplama sonra, 1x PBS sonra kültür ortamı ile yük cihazı yıkayın. 15 dakika boyunca 37 ° C arasında bir sıcaklıkta, cihaz inkübe edin. </li><li> 3-4 x 10 6 hücre / ml &#39;lik bir hücre konsantrasyonu ile% 8 dekstran kültür ortamı içinde HUVEC hücreleri yerleştirin. Cihazın bir girişine bir hücre 20 ul damlacık yerleştirin ve mikroakışkan kanal içine hücreleri tanıtmak için eğilme. 15-20 dakika sonra, hücreler kanallarının yan duvarlara bağlamak için başlayacaktır. Cihaz hücreleri daha homojen bir dağılım oluşturmak için her 15 dakika döndürün. Gerekirse ek yükleme yapılabilir. </li></ol> 4. Uzun vadeli Perfüzyon Kurulum Statik kültür 5-6 saat sonra, ekli HUVEC&#39;lere tam yaymak başlar. 10 ul / saat sürekli bir akış ile bir uzaktan kumandalı şırınga pompası sistemini kullanarak perfüzyon kurun. Perfüzyon F ayarlanabilirya da daha yüksek bir akış hızı, ve 2 hafta ile 4 gün arasında bir süre sürebilir. 5. Hücre Boyama ve Mikroskop Karakterizasyonu <ol><li> Hücre, cihazın içindeki birleştiği ulaştığında, ilk olarak, iyice ortam maddesinin ayrılması için 1X PBS ile yıkayın cihaz. Daha sonra bir seyreltici (4-ul, 1 ml) ile seyreltildi, kırmızı bir boya ile, cihazın yük. Hücre yükleme prosedürüne benzer boya yükleyin. Oda sıcaklığında 5 dakika boyunca karanlıkta inkübe cihazı ve daha sonra boyama durdurmak için kültür ortamı ile yıkayın cihaz. Boya uzun bir kuluçka hücresel toksisite ve disadhesion neden olabilir. </li><li> 1x PBS (ml başına 2 damlacıkları) ile seyreltilmiş mavi boya ile aracı yükleyin. Oda sıcaklığında 5 dakika boyunca karanlıkta inkübe sonra iyice 1X PBS ile yıkayın cihaz. </li><li> Ters bir optik mikroskop altında hücre boyama inceleyin. Boyama iyi ise, (1x PBS ile sulandırılmış% 3.5 paraformaldehid) sabitleme orta mikro yük, daha sonra batığınorta ve tamamen alüminyum folyo ile örtün sabitleme cihazı. 4 arasındaki bir sıcaklıkta buzdolabında cihazını ° C&#39;de kurutarak Photobleaching cihazın önlemek için. Sabit cihaz şimdi konfokal mikroskop bir lazer tarama yapılabilir konfokal görüntüleme, hazır. </li></ol>

Yazarlar hiçbir rakip mali çıkarlarının olmadığını beyan ederim.

<html> 1. Ana kalıp imalat Vasküler morfometri için tasarımı ve yol gösterici ilkelerinden biri ağ boyunca damar çapları dağılımının minimum enerji dikkate tarafından yönetilir belirten Murray yasası 16, olarak bilinir. Ayrıca bir çatallanma bir ana geminin çaplarının küp kızı gemilerin çapları küp toplamına eşittir belirtiyor ( <img alt="Denklem 1" fo:content-width="0.9in" fo:src="/files/ftp_upload/50771/50771eq1.jpg" src="/files/ftp_upload/50771/50771eq...

Mikrodamarlar, dolaşım sisteminin bir parçası olarak, kan ve dokular arasındaki etkileşimi aracılık metabolik faaliyetlerini desteklemek, doku mikro tanımlamak, ve birçok sağlık ve patolojik durumlarda önemli bir rol oynamaktadır. In vitro fonksiyonel mikrodamarlar tekrarlama kompleks vasküler olayların çalışma için bir platform sağlayabilir. Ancak, bu tür endotelyal hücre göçü deneyleri, endotel tüp oluşumu deneyleri, sıçan ve fare aort halkası tahlilleri gibi in vitro mikro-damar deneyleri, geleneksel üç boyutlu (3D) geometrisi ve sürekli bir akış kontrolü ile ilgili olarak, in vivo olarak yeniden kılcal mümkün değildir 1-8. Hayvan modelleri ve bu kornea anjiojen deneyleri, civciv chorioallantoic membran anjiyogenez tahlil ve Matrigel fiş test olarak in vivo deneyleri,, kullanarak mikrodamarlar çalışmaları daha, zaman alıcı maliyeti yüksek, gözlem ve sayımsal ile ilgili zorlu ve olanetik konular 1, 9-13 yükseltmek. Olmazdı böyle kolay ve sıkı kontrol biyolojik koşulları ve dinamik akışkan ortamlar olarak çalışmaları 14, hayvanlarla ve in vivo ilgili yüksek deneysel maliyetleri ve karmaşıklığı yavaşlatmada ise micromanufacturing ve mikroakışkan çip teknolojileri gelişmeler biyomedikal bilimler bakış açıları çeşitli etkin geleneksel makro tekniklerle mümkün. Burada, bir endothelialized oluşturmak için bir yaklaşım mevcut mikro--a-chip in vivo mikrodamarlar içinde 3 boyutlu geometri taklit ve fotolitografik reflowable ışığa tekniği, yumuşak litografi ve Mikroakiskan kombinasyonu kullanarak kontrollü sürekli perfüzyon akış altında çalışır.

<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

In vivo hayvan çalışmaları daha zaman alıcı, pahalı ve gözlem ve miktar çok zor olduğu, çünkü çabaları mikrodamarlar çalışma için in vitro tayinlerde geliştirmeye odaklanmıştır. Üç boyutlu (3D) geometrisi ile ilgili in vivo kılcal temsil eden ve sürekli sıvı akışı sağlayan Ancak, in vitro mikro-damar tahlillerde geleneksel sınırlamaları vardır. Fotolitografik reflowable fotorezist tekniği, yumuşak litografi ve Mikroakiskan bir arada kullanarak, bir çok derinlemesine dairesel kesit endothelialized geliştirdik kontrollü sürekli perfüzyon altında in vivo mikrodamarlar içinde 3 boyutlu geometri taklit ve çalışan, mikro--a-chip akış. Pozitif reflowable ışığa yarım daire kesit Mikrokanallı ağı ile bir ana kalıp imal etmek kullanıldı. Repl iki polidimetilsiloksan (PDMS) mikro uyum ve yapıştırma tarafındanana kalıp gili, silindirik bir Mikrokanallı ağ oluşturuldu. Mikrokanalların çapları iyi kontrol edilebilir. Buna ek olarak, bir çip içerisinde tohumlanmıştır Primer insan göbek bağı damarı endotel hücrelerinin (HUVEC&#39;ler) sonra hücreler, 4 gün ile 2 hafta arasında bir süre boyunca sürekli olarak kontrol edilen perfüzyon altında mikro iç yüzeyi kaplı olduğunu gösterdi.

Çok derinlemesine Mikrokanallı ağ imal yaklaşımımız mikro kesitler 15 yuvarlak var olduğu, in vivo mikrodamarlar içinde karmaşık 3D geometrileri taklit eder. Ayrıca, ana dallanma kanallarının çapları ve kızı kanalları yaklaşık genel kanal direnci düşüktür ve akım hızları ağ 16-18 boyunca daha düzgün böylece gerekli düzeyde sıvı akışı korumak için Murray yasası uyun. Yarım daire şeklinde bir fotorezist ana kalıp, imalat ve dairesel bir yar...

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

Bir mikro-on-a-chip platformu fotolitografik reflowable ışığa tekniği, yumuşak litografi ve Mikroakiskan kombinasyonu tarafından geliştirilmiştir. Endothelialized mikro platformu, in vivo mikrodamar içinde üç boyutlu (3D) geometrisi ile taklit eden sürekli perfüzyon kontrollü akış altında çalışan, yüksek kaliteli ve gerçek zamanlı görüntü sağlar ve mikrovasküler araştırma için uygulanabilir.

Çok derinlemesine Dairesel kesit Endothelialized mikro kanallar-on-a-chip Geliştirme Prosedürü

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 Görüntüleme.  West Virginia University.  Bir mikro-on-a-chip platformu fotolitografik reflowable ışığa tekniği, yumuşak litografi ve Mikroakiskan kombinasyonu tarafından geliştirilmiştir. Endothelialized mikro platformu, in vivo mikrodamar içinde üç boyutlu (3D) geometrisi ile taklit eden sürekli perfüzyon kontrollü akış altında çalışan, yüksek kaliteli ve gerçek zamanlı görüntü sağlar ve mikrovasküler araştırma için uygulanabilir. 

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.

Akciğer Mühendisliği Prosedürü

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

Biyomühendislik

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.

Hematolojik Hastalıklarında Mikrovasküler Etkileşimleri Öğrenmenin Endothelialized Mikroakiskan

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.

Retrograd Koroner Perfüzyon tarafından Domuz Kalp Decellularization Prosedürü

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.

Biyofilm ve Habitat Heterojen Eş-geliştirme karakterize Yöntemleri

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.

Katı Lipit nanopartiküller (SLNs) Hücre içi Hedefleme için başvurular

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.

Zaman-of-flight Kütle Spektrometre ile 2D Gaz Kromatografisi Kullanarak Alg Hidrotermal Sıvılaşma gelen Sulu Kesir Nitel Karakterizasyonu

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.

İnsan bağırsak mukozasının bir Multisellüler Üç boyutlu Organotipik Modelinin Geliştirilmesi yerçekimi Yetiştirilen

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.

Bir Mikro Kuyruklu Dizi Platformunda Mikrobik Topluluk Geliştirmenin Montajı ve Takibi

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.

Ahşap Yapıştırıcıların Yapışkan Mukavemet Gelişimi için Standart Test Yöntemi ASTM D 7998-19

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.

Süspansiyonda Altın Nanopartiküllerin Boyutlandırılması için Asimetrik Akış Alanı-Akış Fraksiyonasyonu

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