Yazarlar, teknik yardım için Chris Morrow kabul etmek istiyorum. Finansman NIH SBIR (R43) tarafından sağlanan 1R43GM101859-01 (MPİ) GRANT10940803 vermek.

1.. Kültür HAZIRLIĞI Hücre <ol><li> Kullanıma hazır olana kadar sıvı azot içinde NIH/3T3 hücre stokları saklayın. </li><li> 50 ug / ml streptomisin,% 10 fetal sığır serumu, 10 mM HEPES tampon maddesi, 50 birim / ml penisilin, ve ile takviye edilmiş Dulbecco Modified Eagle Medium (DMEM) kullanılarak NIH/3T3 hücreleri için tam ortam hazırlayın. </li><li> 37 ° C &#39;de çalkalayıcı bir su banyosu içinde 2-3 dakika için hücreler Çözülme </li><li> 3 dakika boyunca 1,500 x g de tam ortam ve santrifüj içinde 5 ml içinde süspanse hücreler. </li><li> Hücre topaklarını bozmadan hücre süpernatantı. </li><li> Medya 5 ml hücreleri tekrar süspansiyon ve hemasitometre kullanarak hücreleri saymak. <ol><li> Bir 0.5 ml mikrosantrifüj tüpü içinde hücre süspansiyonu ve yerine 10 ul çıkarın. </li><li> Hücre süspansiyonuna Trypan Blue 10 ul ilave edin ve pipet ucu ile karıştırın. </li><li> Pipet bir hemositometre odasına boyanmış hücrelerin 10 ul. </li><li> 10x hemositometrede hücreleri saymakbüyütme. <ol><li> 9 büyük kareler 4 için canlı hücreleri (küçük, beyaz top) saymak. Sadece Tripan Mavi leke koyu mavi görünmüyor canlı hücreleri saymak. </li><li> Hücreler orijinal hücre süspansiyon içinde 4 x 10 hücre / ml sayısının sonuçlanan büyük kare başına hücrelerin ortalama sayısını hesaplayın. </li><li> 1 x10 her bir T25 şişesi içinde, 5 ml toplam 5 hücre / ml bir yoğunlukta tohum hücreleri. </li></ol></li><li> Başlamadan deneylerden önce,% 70 ve% 80 confluency arasına Kültür hücreleri. Gerektiğinde her 2-3 gün medya Yenile ya. </li></ol></li></ol> 2.. Baskı Yüzey Hazırlama <ol><li> Mark, bir doku kültürü ile muamele edilmiş polistiren (TCTPS) 12 çukurlu levha altındaki işaretleyici ile bir dikdörtgen baskı kafası (19 mm x 7 mm) boyutudur. </li><li> Pipet 50 dikdörtgen alanı içine fetal sığır serumu ul ve ucu ile tüm bölge üzerine yayıldı. </li><li> Petri kabı bırakınSteril bir biyogüvenlik kaput O / N serum nokta tamamen kuruması için. Bu plakalar kullanmak için en fazla 2 gün önce hazırlanmalıdır. </li></ol> 3.. Batık Baskı <ol><li> Distile su ile baskı kafasını durulayın. <ol><li> Damıtılmış su ile bir 60 mm Petri kabı doldurmak ve yüzey üzerine baskı kafası rıhtım. </li><li> Pnömatik bir pompa kullanılarak 150 ul / dakika ile 2 dakika boyunca çizgilerin her birinden damıtılmış su akış. </li><li> Petri kabı suyu atmak ve temiz su ile doldurun. </li><li> Su yukarı ve aşağı 3 kez baskı kafasını hareket ettirin. </li></ol></li><li> Önceden hazırlanmış 12 oyuklu bir plaka içerisinde serum kaplı nokta üzerinde baskı kafası merkezi olarak yerleştirir. </li><li> Başbakan önceden ısıtılmış eksiksiz bir medya, kanal başına 300 ul ile baskı kafası. </li><li> Baskı, bir yüzey üzerine 50,000 hücre / ml &#39;lik konsantrasyon ile 60 ul / dk, kanal başına 100 ul süspansiyon hücreleri. </li><li> Karşı demirledi sol baskı kafasını, yerleştirinyüzey ve bir hücre kültürü inkübatöründe manifold 2 saat boyunca% 5 CO2 ile 37 ° C olarak ayarlanır. </li><li> 2 saat inkübasyondan sonra, baskı kafası çıkarın ve kültür çanağı üzerindeki kapağı yerleştirin. Yazıcı kafası kaldırıldı hangi süre 0 saat zaman noktası olarak kabul edilir. </li></ol> 4. Standard Hücre Kültürü <ol><li> Aşama 2&#39;de hazırlanan serum benekli TCTPS 12 oyuklu plaka birine önceden ısıtılmış ortam 1 ml ilave edilir. </li><li> Bir 12-yuvalı plaka TCTPS tek bir kuyuya pipetle adım 2 ve geri kalan hücre süspansiyonu 1 ml al. Bu tabak içinde 50,000 hücre ihtiva eden bir kültür üretecektir. </li><li> 2 saat boyunca 37 ° C&#39;de bir inkübatör içinde, hücre kültürü plakası yerleştirin. </li><li> 2 saat kuluçka zamanlaması başladıktan sonra; baskılı ve tohum örnekleri arasındaki tutarlılık için, bu 0 hr zaman noktası olarak kabul edilir. </li></ol> 5. Kültür Görselleştirme <ol><li> 0, 2, 24, ve iki yöntemlerin her biri 48 saat sonra, germe hücre dStandart bir ters mikroskop kullanılarak, yukarıda ve görüntü TANIMLANMIŞ. <ol><li> Propidyum iyodür, sadece ölü hücre çekirdeği içine dahil edilen kırmızı bir floresan boya kullanarak hücreleri Leke. <ol><li> Yavaşça kalsiyum ve pislikleri kaldırmak magnezyum (PBS + +) ile fosfat tamponlu tuzlu su, 1 ml ile hücreler 3 kez yıkayın. </li><li> Her bir kültür teknesine, önceden ısıtılmış PBS + + 1 ml ilave edilir. </li><li> Her bir kültür teknesine propidyum iyodür stok çözeltisi (1 mg / ml) 1 ul ekle. </li><li> 10 dakika boyunca 37 ° C &#39;de propidyum iyodürle boyanan hücreleri inkübe edin. </li></ol></li><li> Görüntü ters bir 10x ve 40x büyütme mikroskop kullanarak hücreleri. </li></ol></li><li> Uygun bir biohazard konteyner hücreleri atın. </li></ol>

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Yazarlar reaktifler ve / veya bu metinde kullanılan aletleri üreten Wasatch Microfluidics çalışanı ve hissedarları vardır.

Burada anlatılan 3D mikroakışkan baskı teknolojisi, iyi doldurulmuş bir sıvının içine hücre microfluidically baskı dizilerin benzersiz yeteneğine sahip bir batık yüzeyini yani. Batık yüzeyleri üzerine baskı ile, hücre mikroarray&#39;ler hücrelerin fizyolojik olarak ilgili hücre fenotipi hem de tek bir iyi Şekil 4&#39;ün alt hücreleri multiplex yeteneğini korumak üretilebilir. Microfluidically hücreleri sonuçlar baskı Bu çalışmanın sonuçları, karşılaştırıl...

Ilaç endüstrisinde son gelişmeler, ilaç tarama ve cytotoxicological analiz 1,2,3 için ilaç keşfi sürecinde hücresel mikrodiziler kullanarak artan ilgi yol açmıştır. Hücre mikrodizileri kullanılarak in vitro yüksek verimli tarama deneyleri ve yöntemlerinin geliştirilmesi, hızlı ve düşük maliyetli bir ilaç adaylarının gelişimi hem de önceden hücrenin 1,4 temel anlayışı kolaylaştıracaktır. Hücreleri ile tarama için geleneksel yaklaşım, geleneksel iyi-plaka platformları kullanır; Ancak bu yaklaşım nedeniyle yüksek maliyet, sınırlı verim ve hücre fonksiyonu 1,5 nicel bilgi için sınırlı yeteneği sınırlıdır. Bu sınırlamalar nedeniyle, hücresel mikroarray teknolojileri araştırma moleküler biyolojik karakterizasyonu, doku mühendisliği ve ilaç tarama 1,6 için gelişen edilir. Hücresel microarrays avantajları küçük bir örnek kullanımı, minimal etkilerini içerirhücresel fenotip heterojenite bilgi maskeleme ve daha yüksek hacimli uygulamalar 1,7,8 için tahliller otomatikleştirmek için en önemlisi yetenek. Farmasötik sanayi şu anda mikrotiter yuvalı plakalar 9 ilaç taraması için 2B hücre tek-tabakalı kültürler ile yüksek yayılmalı hücre bazlı bir tarama tahlilleri kullanır. Mikrotitre plakalara çoğullama hücreleri özgün deney seçenekleri ile daha yüksek verim için potansiyel sunmaktadır. Bundan başka, hücre mikrodizilerinde mevcut teknolojiler, hücreler, in vivo önemli ölçüde 10,11 gelen hücrelerin fenotipinin değiştirebilir ki kurumaya bırakın. Bu sorunların üstesinden gelmek için, MFCA tasarlanmış ve Şekil 1 &#39;de gösterilmiştir. MFCA 3D akışkansal tasarımı bir banyoya daldırılır ve bir yalıtım oluşturmak için bir yüzeye karşı sıkıştırılmak üzere, Şekil 1&#39; deki baskı kafası ucu sağlar. Kafasının yumuşak silikon ucu gibi davranırConta ve geri dönüşümlü bir mühür oluşturur. MFCA teknolojisi, özellikle, hücre kültürleri, doku dilim sistemler için gerekli olan batık yüzeyleri ile arabirim oluşturmak için uygun, ve diğer yaklaşımlar ile zor veya imkansız olur. Pimleri veya mürekkep püskürtmeli baskı çalışmaz, ve 2D mikroakışkan cihazlar birikimi veya ayrık noktalar büyük diziler ile arabirim için uygun değildir. Bundan başka, deney minyatürleştirme ve lokalize ile - hücresel mikro-dizi - MFCA, yüksek yayılmalı hücre bazlı tarama deneyleri ile ilgili önemli problemlerin üstesinden gelmektedir. CFM bir yüzey 12,13 mikroskobik nokta yerlerine bisikletle küçük hacimli sıvı örneklerinin 3D kanal ağlarını kullanır. Akış ile baskı ile, biyomoleküller, hücreler ve diğer reaktifler, mevcut hücre baskı teknikleri engellemektedir hava, maruz kalmadan hassas biyomoleküllerin ve hücrelerin baskı sağlayan, baskı işlemi boyunca sıvı bir ortamda muhafaza edilir. Bu dizi yüzeyde bir yakalama mekanizması vardır örneğin, hibridoma süpernatanları ya da sağlanan gibi ham malzeme doğrudan baskı için de mümkündür. Bu yazının amacı, bir yüzey üzerine ayrıntılı olarak, iki hücre tiplerinin batık baskı açıklamaktır.

<table border="0" cellpadding="0" cellspacing="0" width="571">
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:215px;">Continuous Flow Microspotter</td>
			<td style="width:71px;">Wasatch Microfluidics</td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">NIH/3T3 cells</td>
			<td style="width:71px;">ATCC</td>
			<td style="width:119px;">CRL-1658</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Dubbleco&#39;s Modified Eagle Medium</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">11965-092</td>
			<td>base media for cells</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">HEPES buffer</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">15630-080</td>
			<td>cell media additive (control pH)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Sodium pyruvate</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">11360-070</td>
			<td>cell media additive</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Penicillin-Streptomycin&#160;</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;"></td>
			<td>cell media additive</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Trypan blue</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">15250-061</td>
			<td>stain cell sfor counting</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Haemocytometer</td>
			<td style="width:71px;">Fisher</td>
			<td align="right" style="width:119px;">267110</td>
			<td>cell chamber to count cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Nikon Eclipse TS100</td>
			<td style="width:71px;">Nikon</td>
			<td style="width:119px;"></td>
			<td>Used to check on cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Nikon Eclipse TE2000-U</td>
			<td style="width:71px;">Nikon</td>
			<td style="width:119px;"></td>
			<td>Used for collecting images</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Phosphate Buffered Saline (with calcium and magnesium)</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">14040-133</td>
			<td>rinsing cells before passaging and before staining with PI</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">TrypLE Express&#160;</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">A12177-01</td>
			<td>used to remove cells from surface</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;"></td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

the submerged printing of cells onto a modified surface using a continuous flow microspotter

The printing of cells for microarray applications possesses significant challenges including the problem of maintaining physiologically relevant cell phenotype after printing, poor organization and distribution of desired cells, and the inability to deliver drugs and/or nutrients to targeted areas in the array. Our 3D microfluidic printing technology is uniquely capable of sealing and printing arrays of cells onto submerged surfaces in an automated and multiplexed manner. The design of the microfluidic cell array (MFCA) 3D fluidics enables the printhead tip to be lowered into a liquid-filled well or dish and compressed against a surface to form a seal. The soft silicone tip of the printhead behaves like a gasket and is able to form a reversible seal by applying pressure or backing away. Other cells printing technologies such as pin or ink-jet printers are unable to print in submerged applications. Submerged surface printing is essential to maintain phenotypes of cells and to monitor these cells on a surface without disturbing the material surface characteristics. By printing onto submerged surfaces, cell microarrays are produced that allow for drug screening and cytotoxicity assessment in a multitude of areas including cancer, diabetes, inflammation, infections, and cardiovascular disease.

Fibroblast hücre hattı NIH/3T3 hücreler, bir dalgıç yüzey üzerine basılı veya ekilmiştir. Hücreler, ml başına 5 x 10 4 hücre yoğunluğuna kadar büyütülmüştür. Hücreler, geleneksel hücre kültürü teknikleri kullanılarak ekilmiştir. Hücreler, geniş ebatlı, kanal proteinleri ve diğer biyomoleküllerin için kullanılan daha CFM (~ 500 um) daha büyük olan on iki akış hücresi baskı kafası kullanılarak basıldı. Hücreler serum kaplı yüzey üzerine basılı veya ekilmiştir...

Watch this Scientific Journal Video about The Submerged Printing of Cells onto a Modified Surface Using a Continuous Flow Microspotter at JoVE.com

The Submerged Printing of Cells onto a Modified Surface Using a Continuous Flow Microspotter

This 3D microfluidic printing technology prints arrays of cells onto submerged surfaces. We describe how arrays of cells are delivered microfluidically in 3D flow cells onto submerged surfaces. By printing onto submerged surfaces, cell microarrays were produced that allow for drug screening and cytotoxicity assessment in a multitude of areas.

Sürekli Akış Microspotter kullanma Modifiye yüzeye hücrelerin Batık Baskı

The printing of cells for microarray applications possesses significant challenges including the problem of maintaining physiologically relevant cell ...

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Research

JoVE Journal

Bioengineering

8.7K Görüntüleme.  Wasatch Microfluidics. This 3D microfluidic printing technology prints arrays of cells onto submerged surfaces. We describe how arrays of cells are delivered microfluidically in 3D flow cells onto submerged surfaces. By printing onto submerged surfaces, cell microarrays were produced that allow for drug screening and cytotoxicity assessment in a multitude of areas.

Video: The Submerged Printing of Cells onto a Modified Surface Using a Continuous Flow Microspotter

Measurement of Aggregate Cohesion by Tissue Surface Tensiometry

Rigorous measurement of intercellular binding energy can only be made using methods grounded in thermodynamic principles in systems at equilibrium. We have developed tissue surface tensiometry (TST) specifically to measure the surface free energy of interaction between cells. The biophysical concepts underlying TST have been previously described in detail1,2. The method is based on the observation that mutually cohesive cells, if maintained in shaking culture, will spontaneously assemble into clusters. Over time, these clusters will round up to form spheres. This rounding-up behavior mimics the behavior characteristic of liquid systems. Intercellular binding energy is measured by compressing spherical aggregates between parallel plates in a custom-designed tissue surface tensiometer. The same mathematical equation used to measure the surface tension of a liquid droplet is used to measure surface tension of 3D tissue-like spherical aggregates. The cellular equivalent of liquid surface tension is intercellular binding energy, or more generally, tissue cohesivity. Previous studies from our laboratory have shown that tissue surface tension (1) predicts how two groups of embryonic cells will interact with one another1-5, (2) can strongly influence the ability of tissues to interact with biomaterials6, (3) can be altered not only through direct manipulation of cadherin-based intercellular cohesion7, but also by manipulation of key ECM molecules such as FN8-11 and 4) correlates with invasive potential of lung cancer12, fibrosarcoma13, brain tumor14 and prostate tumor cell lines15. In this article we will describe the apparatus, detail the steps required to generate spheroids, to load the spheroids into the tensiometer chamber, to initiate aggregate compression, and to analyze and validate the tissue surface tension measurements generated.

We describe a method of measuring binding energy, expressible as tissue surface tension, between cells within 3D tissue-like aggregates. Differences in tissue surface tension have been demonstrated to correlate with invasiveness of lung, muscle, and brain tumors, and are fundamental determinants of establishing spatial relationships between different cell types.

Doku Yüzey tensiometresi Agrega Uyum ölçümü

Rigorous measurement of intercellular binding energy can only be made using methods grounded in thermodynamic principles in systems at equilibrium.  We ...

Biyomühendislik

Planar and Three-Dimensional Printing of Conductive Inks

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical devices1-3. In this paper, we focus on one- (1D), two- (2D), and three-dimensional (3D) printing of conductive metallic inks in the form of flexible, stretchable, and spanning microelectrodes.
Direct-write assembly4,5 is a 1-to-3D printing technique that enables the fabrication of features ranging from simple lines to complex structures by the deposition of concentrated inks through fine nozzles (~0.1 - 250 &mu;m). This printing method consists of a computer-controlled 3-axis translation stage, an ink reservoir and nozzle, and 10x telescopic lens for visualization. Unlike inkjet printing, a droplet-based process, direct-write assembly involves the extrusion of ink filaments either in- or out-of-plane. The printed filaments typically conform to the nozzle size. Hence, microscale features (&lt; 1 &mu;m) can be patterned and assembled into larger arrays and multidimensional architectures.
In this paper, we first synthesize a highly concentrated silver nanoparticle ink for planar and 3D printing via direct-write assembly. Next, a standard protocol for printing microelectrodes in multidimensional motifs is demonstrated. Finally, applications of printed microelectrodes for electrically small antennas, solar cells, and light-emitting diodes are highlighted.

Planar and three-dimensional printing of conductive metallic inks is described. Our approach provides new avenues for fabricating printed electronic, optoelectronic, and biomedical devices in unusual layouts at the microscale.

İletken Mürekkepler düzlemsel ve Üç Boyutlu Baskı

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical ...

Parallel-plate Flow Chamber and Continuous Flow Circuit to Evaluate Endothelial Progenitor Cells under Laminar Flow Shear Stress

The overall goal of this method is to describe a technique to subject adherent cells to laminar flow conditions and evaluate their response to well quantifiable fluid shear stresses1.
Our flow chamber design and flow circuit (Fig. 1) contains a transparent viewing region that enables testing of cell adhesion and imaging of cell morphology immediately before flow (Fig. 11A, B), at various time points during flow (Fig. 11C), and after flow (Fig. 11D). These experiments are illustrated with human umbilical cord blood-derived endothelial progenitor cells (EPCs) and porcine EPCs2,3.
This method is also applicable to other adherent cell types, e.g. smooth muscle cells (SMCs) or fibroblasts.
The chamber and all parts of the circuit are easily sterilized with steam autoclaving. In contrast to other chambers, e.g. microfluidic chambers, large numbers of cells (&gt; 1 million depending on cell size) can be recovered after the flow experiment under sterile conditions for cell culture or other experiments, e.g. DNA or RNA extraction, or immunohistochemistry (Fig. 11E), or scanning electron microscopy5. The shear stress can be adjusted by varying the flow rate of the perfusate, the fluid viscosity, or the channel height and width. The latter can reduce fluid volume or cell needs while ensuring that one-dimensional flow is maintained. It is not necessary to measure chamber height between experiments, since the chamber height does not depend on the use of gaskets, which greatly increases the ease of multiple experiments. Furthermore, the circuit design easily enables the collection of perfusate samples for analysis and/or quantification of metabolites secreted by cells under fluid shear stress exposure, e.g. nitric oxide (Fig. 12)6.

We are describing a method to subject adherent cells to laminar flow shear stress in a sterile continuous flow circuit. The cells' adhesion, morphology can be studied through the transparent chamber, samples obtained from the circuit for metabolite analysis and cells harvested after shear exposure for future experiments or culture.

Laminer Akış Kesme Stres altında endotel progenitör hücrelerin değerlendirin Paralel plakalı Akış Odası ve Sürekli Akış Devre

The overall goal of this method is to describe a technique to subject adherent cells to laminar flow conditions and evaluate their response to well ...

Measuring the Mechanical Properties of Living Cells Using Atomic Force Microscopy

Mechanical properties of cells and extracellular matrix (ECM) play important roles in many biological processes including stem cell differentiation, tumor formation, and wound healing. Changes in stiffness of cells and ECM are often signs of changes in cell physiology or diseases in tissues. Hence, cell stiffness is an index to evaluate the status of cell cultures. Among the multitude of methods applied to measure the stiffness of cells and tissues, micro-indentation using an Atomic Force Microscope (AFM) provides a way to reliably measure the stiffness of living cells. This method has been widely applied to characterize the micro-scale stiffness for a variety of materials ranging from metal surfaces to soft biological tissues and cells. The basic principle of this method is to indent a cell with an AFM tip of selected geometry and measure the applied force from the bending of the AFM cantilever. Fitting the force-indentation curve to the Hertz model for the corresponding tip geometry can give quantitative measurements of material stiffness. This paper demonstrates the procedure to characterize the stiffness of living cells using AFM. Key steps including the process of AFM calibration, force-curve acquisition, and data analysis using a MATLAB routine are demonstrated. Limitations of this method are also discussed.

This paper demonstrates a protocol to characterize the mechanical properties of living cells by means of microindentation using an Atomic Force Microscope (AFM).

Atomik Kuvvet Mikroskobu kullanarak Yaşam Hücrelerinin Mekanik Özellikleri Ölçme

Mechanical  properties of cells and extracellular matrix (ECM) play important roles in many  biological processes including stem cell differentiation, ...

Automated Robotic Dispensing Technique for Surface Guidance and Bioprinting of Cells

This manuscript describes the introduction of cell guidance features followed by the direct delivery of cells to these features in a hydrogel bioink using an automated robotic dispensing system. The particular bioink was selected as it allows cells to sediment towards and sense the features. The dispensing system bioprints viable cells in hydrogel bioinks using a backpressure assisted print head. However, by replacing the print head with a sharpened stylus or scalpel, the dispensing system can also be employed to create topographical cues through surface etching. The stylus movement can be programmed in steps of 10 &#181;m in the X, Y and Z directions. The patterned grooves were able to orientate mesenchymal stem cells, influencing them to adopt an elongated morphology in alignment with the grooves&#39; direction. The patterning could be designed using plotting software in straight lines, concentric circles, and sinusoidal waves. In a subsequent procedure, fibroblasts and mesenchymal stem cells were suspended in a 2% gelatin bioink, for bioprinting in a backpressure driven extrusion printhead. The cell bearing bioink was then printed using the same programmed coordinates used for the etching. The bioprinted cells were able to sense and react to the etched features as demonstrated by their elongated orientation along the direction of the etched grooves.

This protocol describes a bioprinting methodology using an automated robotic depositing system that incorporates etched topographical guidance cues with the precision deposition of a cell bearing hydrogel bioink. The printed cells are directly delivered to the etched features and are able to sense and orientate with them.

Hücre Yüzey Rehberlik ve Bioprinting için Otomatik Robotik Dağıtım Tekniği

This manuscript describes the introduction of cell guidance features followed by the direct delivery of cells to these features in a hydrogel bioink using ...

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.

Stres birden çok paralel-plaka akışı Chambers kullanarak yamultmak için maruz endotel hücrelerinin gen ifade Analizi

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

An Automated Method to Perform The In Vitro Micronucleus Assay using Multispectral Imaging Flow Cytometry

The in vitro micronucleus (MN) assay is often used to evaluate cytotoxicity and genotoxicity but scoring the assay via manual microscopy is laborious and introduces uncertainty in results due to variability between scorers. To remedy this, automated slide-scanning microscopy as well as conventional flow cytometry methods have been introduced in an attempt to remove scorer bias and improve throughput. However, these methods have their own inherent limitations such as inability to visualize the cytoplasm of the cell and the lack of visual MN verification or image data storage with flow cytometry. Multispectral Imaging Flow Cytometry (MIFC) has the potential to overcome these limitations. MIFC combines the high resolution fluorescent imagery of microscopy with the statistical robustness and speed of conventional flow cytometry. In addition, all collected imagery can be stored in dose-specific files. This paper describes the protocol developed to perform a fully automated version of the MN assay on MIFC. Human lymphoblastoid TK6 cells were enlarged using a hypotonic solution (75 mM KCl), fixed with 4% formalin and the nuclear content was stained with Hoechst 33342. All samples were run in suspension on the MIFC, permitting acquisition of high resolution images of all key events required for the assay (e.g. binucleated cells with and without MN as well as mononucleated and polynucleated cells). Images were automatically identified, categorized and enumerated in the MIFC data analysis software, allowing for automated scoring of both cytotoxicity and genotoxicity. Results demonstrate that using MIFC to perform the in vitro MN assay allows statistically significant increases in MN frequency to be detected at several different levels of cytotoxicity when compared to solvent controls following exposure of TK6 cells to Mitomycin C and Colchicine, and that no significant increases in MN frequency are observed following exposure to Mannitol.

The in vitro micronucleus assay is a well-established method for evaluating genotoxicity and cytotoxicity but scoring the assay using manual microscopy is laborious and suffers from subjectivity and inter-scorer variability. This paper describes the protocol developed to perform a fully automated version of the assay using multispectral imaging flow cytometry.

Multispectral görüntüleme akışı sitometrisi kullanarak In vitro micronucleus assay gerçekleştirmek için otomatik bir yöntem

The in vitro micronucleus (MN) assay is often used to evaluate cytotoxicity and genotoxicity but scoring the assay via manual microscopy is laborious and ...

Continuous Measurement of Biological Noise in Escherichia Coli Using Time-lapse Microscopy

The protocol developed here offers a tool to enable computer tracking of Escherichia coli division and fluorescent levels over several hours. The process starts by screening for colonies that survive on minimal media, assuming that only Escherichia coli harboring the correct plasmid will be able to thrive in the specific conditions. Since the process of building large genetic circuits, requiring the assembly of many DNA parts, is challenging, circuit components are often distributed between multiple plasmids at different copy numbers requiring the use of several antibiotics. Mutations in the plasmid can destroy transcription of the antibiotic resistance genes and interject with resources management in the cell leading to necrosis. The selected colony is set on a glass-bottom Petri dish and a few focus planes are selected for microscopy tracking in both bright field and fluorescent domains. The protocol maintains the image focus for more than 12 hours under initial conditions that cannot be regulated, creating a few difficulties. For example, dead cells start to accumulate in the lenses' field of focus after a few hours of imaging, which causes toxins to buildup and the signal to blur and decay. Depletion of nutrients introduces new metabolic processes and hinder the desired response of the circuit. The experiment's temperature lowers the effectivity of inducers and antibiotics, which can further damage the reliability of the signal. The minimal media gel shrinks and dries, and as a result the optical focus changes over time. We developed this method to overcome these challenges in Escherichia coli, similar to previous works developing analogous methods for other micro-organisms. In addition, this method offers an algorithm to quantify the total stochastic noise in unaltered and altered cells, finding that the results are consistent with flow analyzer predictions as shown by a similar coefficient of variation (CV).

Continuous Measurement of Biological Noise in Escherichia Coli Using Time-lapse Microscopy

This work presents a microscopy method that allows live imaging of a single cell of Escherichia coli for analysis and quantification of the stochastic behavior of synthetic gene circuits.

Zaman Atlamalı Mikroskopi Kullanılarak Escherichia Coli'de Biyolojik Gürültünün Sürekli Ölçümü

The protocol developed here offers a tool to enable computer tracking of Escherichia coli division and fluorescent levels over several hours. The process ...

The Fabrication and Operation of a Continuous Flow, Micro-Electroporation System with Permeabilization Detection

Current therapeutic innovations, such as CAR-T cell therapy, are heavily reliant on viral-mediated gene delivery. Although efficient, this technique is accompanied by high manufacturing costs, which has brought about an interest in using alternative methods for gene delivery. Electroporation is an electro-physical, non-viral approach for the intracellular delivery of genes and other exogenous materials. Upon the application of an electric field, the cell membrane temporarily allows molecular delivery into the cell. Typically, electroporation is performed on the macroscale to process large numbers of cells. However, this approach requires extensive empirical protocol development, which is costly when working with primary and difficult-to-transfect cell types. Lengthy protocol development, coupled with the requirement of large voltages to achieve sufficient electric-field strengths to permeabilize the cells, has led to the development of micro-scale electroporation devices. These micro-electroporation devices are manufactured using common microfabrication techniques and allow for greater experimental control with the potential to maintain high throughput capabilities. This work builds off a microfluidic-electroporation technology capable of detecting the level of cell membrane permeabilization at a single-cell level under continuous flow. However, this technology was limited to 4 cells processed per second, and thus a new approach for increasing the system throughput is proposed and presented here. This new technique, denoted as cell-population-based feedback control, considers the cell permeabilization response to a variety of electroporation pulsing conditions and determines the best-suited electroporation pulse conditions for the cell type under test. A higher-throughput mode is then used, where this 'optimal' pulse is applied to the cell suspension in transit. The steps for fabricating the device, setting up and running the microfluidic experiments, and analyzing the results are presented in detail. Finally, this micro-electroporation technology is demonstrated by delivering a DNA plasmid encoding for green fluorescent protein (GFP) into HEK293 cells.

This protocol describes the microfabrication techniques required to build a lab-on-a-chip, microfluidic electroporation device. The experimental setup performs controlled, single-cell-level transfections in a continuous flow and can be extended to higher throughputs with population-based control. An analysis is provided showcasing the ability to electrically monitor the degree of cell membrane permeabilization in real-time.

Sürekli akışlı, permeabilizasyon algılamalı mikro-elektroporasyon sisteminin imalatı ve işletilmesi

Current therapeutic innovations, such as CAR-T cell therapy, are heavily reliant on viral-mediated gene delivery. Although efficient, this technique is ...

Fabrication of Engineered Vascular Flaps Using 3D Printing Technologies

Engineering implantable, functional, thick tissues requires designing a hierarchical vascular network. 3D bioprinting is a technology used to create tissues by adding layer upon layer of printable biomaterials, termed bioinks, and cells in an orderly and automatic manner, which allows for creating highly intricate structures that traditional tissue engineering techniques cannot achieve. Thus, 3D bioprinting is an appealing in vitro approach to mimic the native vasculature complex structure, ranging from millimetric vessels to microvascular networks. 
Advances in 3D bioprinting in granular hydrogels enabled the high-resolution extrusion of low-viscosity extracellular matrix-based bioinks. This work presents a combined 3D bioprinting and sacrificial mold-based 3D printing approach for fabricating engineered vascularized tissue flaps. 3D bioprinting of endothelial and support cells using recombinant collagen-methacrylate bioink within a gelatin support bath is utilized for the fabrication of a self-assembled capillary network. This printed microvasculature is assembled around a mesoscale vessel-like porous scaffold, fabricated using a sacrificial 3D printed mold, and is seeded with endothelial cells. 
This assembly induces the endothelium of the mesoscale vessel to anastomose with the surrounding capillary network, establishing a hierarchical vascular network within an engineered tissue flap. The engineered flap is then directly implanted by surgical anastomosis to a rat femoral artery using a cuff technique. The described methods can be expanded for the fabrication of various vascularized tissue flaps for use in reconstruction surgery and vascularization studies.

Engineered flaps require an incorporated functional vascular network. In this protocol, we present a method of fabricating a 3D printed tissue flap containing a hierarchical vascular network and its direct microsurgical anastomoses to rat femoral artery.

3D Baskı Teknolojileri Kullanılarak Mühendislik Vasküler Flaplarının İmalatı

Engineering implantable, functional, thick tissues requires designing a hierarchical vascular network. 3D bioprinting is a technology used to create ...