著者は、技術支援のためのクリス·モローを承認したいと思います。資金は、NIH SBIR（R43）助成1R43GM101859-01（MPI）GRANT10940803によって提供された。

1。細胞培養の準備<ol><li>使用するまで液体窒素中でNIH/3T3細胞株を保管してください。 </li><li> 10％ウシ胎児血清を補充したダルベッコ改変イーグル培地（DMEM）を用いてNIH/3T3細胞について完全培地を調製し、10mMのHEPES緩衝液、50単位/ mlペニシリン、および50μg/ mlのストレプトマイシン。 </li><li> 37℃にて振とう水浴中で2〜3分間、細胞を解凍</li><li> 3分間1500×gで完全なメディアや遠心分離機の5ミリリットル中の細胞を再懸濁。 </li><li>細胞ペレットを乱すことなく細胞上清を取り除きます。 </li><li>メディア5mlに細胞を再懸濁し、血球計数器を用いて細胞を数える。 <ol><li> 0.5ミリリットルのマイクロチューブに細胞懸濁液と場所を10μlを削除します。 </li><li>細胞懸濁液にトリパンブルー10μlのを追加し、ピペットのチップでかき混ぜる。 </li><li>血球計数器室への染色された細胞のピペットを10μl。 </li><li> 10倍で血球計数器で細胞を数える倍率。 <ol><li> 9大正方形の4のために生きている細胞（小さな白いボールを）カウントします。トリパンブルー染色から濃い青色に表示されない、生きた細胞のみをカウントします。 </li><li>細胞は元の細胞懸濁液中の×10 4細胞/ mlの数を生じ、大きい正方形当たりの細胞の平均数を計算する。 </li><li> 1×10各T25フラスコ中の5mlを合計5細胞/ mlの密度で種子細胞。 </li></ol></li><li> 70％〜80％の集密度に培養細胞の実験を開始する前に。必要に応じて2〜3日ごとにメディアを更新するか。 </li></ol></li></ol> 2。印刷面の準備<ol><li>マーク·組織培養処理ポリスチレン（TCTPS）12ウェルプレートの底面にあるマーカーを持つ矩形のプリントヘッド（X 19ミリメートル7ミリメートル）の大きさ。 </li><li>ピペット50の矩形領域にウシ胎児血清のμLとチップとの全域に広げる。 </li><li>ペトリ皿を残す無菌バイオセーフティーフードのO / Nにおいて血清スポットが完全に乾燥することができます。これらのプレートは、使用前にこれ以上の2日以上を準備する必要があります。 </li></ol> 3。サブマージ印刷<ol><li>蒸留水でプリントヘッドをすすぐ。 <ol><li>蒸留水で60ミリメートルペトリ皿を記入し、表面にプリントヘッドをドッキング。 </li><li>空気ポンプを用いて150μlの/分で2分間線のそれぞれを介して蒸留水を流す。 </li><li>ペトリ皿から水を捨て、きれいな水でそれを埋める。 </li><li>水中で上下に3回プリントヘッドを移動します。 </li></ol></li><li>事前準備12ウェルプレート中の血清でコーティングされたスポット上でプリントヘッドの中心をドッキング。 </li><li>プライム予め温め完全なメディア、チャネルあたり300μlのプリントヘッド。 </li><li>印刷面に50,000細胞/ mlの濃度で細胞を懸濁し、60μL/分、チャンネルあたり100μL。 </li><li>プリントヘッドを置き、反対ドッキング左表面、および2時間、5％CO 2、37℃に設定し、細胞培養インキュベーター中でマニホールド。 </li><li> 2時間インキュベートした後、プリントヘッドを取り外して、培養皿にふたをする。プリントヘッドが除去される時間は、0時間の時点と考えられる。 </li></ol> 4。標準的な細胞培養<ol><li>ステップ2で調製した血清を点着TCTPS 12ウェルプレートの1に予め温めメディアの1ミリリットルを追加します。 </li><li> 12ウェルTCTPSプレートの単一ウェルにステップ2とピペットから残りの細胞懸濁液の1ミリリットルを取る。これは皿に50,000細胞を含む培養が生成されます。 </li><li> 2時間37℃のインキュベーター内で細胞培養プレートを置きます。 </li><li> 2時間インキュベートした後のタイミングを始める。印刷され、播種サンプル間の一貫性のために、これを0時間の時点と考えられている。 </li></ol> 5。文化の可視化<ol><li> 0,2、24、及び二つの方法の各々からの48時間のテイク細胞日後標準の倒立顕微鏡を用いて上記画像傍接した。 <ol><li>ヨウ化プロピジウムのみ死細胞の核内に組み込まれる赤色蛍光染色を用いて細胞を染色する。 <ol><li>穏やかに任意の破片を除去するために、カルシウムおよびマグネシウムを含むリン酸緩衝生理食塩水（PBS + +）1mlで細胞を3回すすぐ。 </li><li>各培養容器に予め温めPBS + +の1ミリリットルを追加します。 </li><li>各培養容器にヨウ化プロピジウム原液（1 mg / ml）をの1を添加する。 </li><li> 10分間37℃で、ヨウ化プロピジウムで染色した細胞をインキュベートする。 </li></ol></li><li>イメージ細胞を10倍と40倍の倍率で倒立顕微鏡を使用。 </li></ol></li><li>適切なバイオハザード容器にセルを廃棄。 </li></ol>

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著者らは、この原稿に使用される試薬および/または楽器を生産ワサッチマイクロ流体工学の従業員と株主である。

ここで説明した3Dマイクロ流体印刷技術は、よく充填された液体への細胞のmicrofluidically印刷アレイの一意ができる水没面、すなわち 。水没面に印刷することによって、細胞マイクロアレイは、細胞の生理学的に関連する細胞表現型ならびに単一ウェル、図4の底部に細胞を多重化する能力を維持するように製造することができる。microfluidically中の細胞の結果を印刷するこ?...

製薬業界における最近の進歩は、薬物スクリーニングおよび分析cytotoxicological 1,2,3ための創薬プロセスにおける細胞マイクロアレイを使用して関心の高まりをもたらした。細胞マイクロアレイを用いたin vitroハイスループットアッセイおよびスクリーニング方法の開発は、迅速かつ費用対効果の高い薬剤候補の開発、ならびに、予めセル1,4の基本的な理解を容易にするであろう。細胞を用いたスクリーニングに伝統的なアプローチは、従来のウェルプレートのプラットフォームを使用しています。しかしながら、このアプローチは、高いコスト、限定されたスループット、および細胞機能に関する定量1,5については限られた能力に制限される。原因これらの制限があるため、携帯マイクロアレイ技術の研究は、分子生物学的特性評価、組織工学、および薬剤スクリーニング1,6のために急成長されている。携帯マイクロアレイの利点は、より小さなサンプルを使用、最小限の影響を含む細胞表現型情報をマスキング異質性、そして最も重要なことには、より高いスループットアプリケーション1,7,8するためのアッセイを自動化する能力。 製薬業界は、現在、マイクロタイターウェルプレート9における薬物スクリーニングのための2D細胞単層培養物とのハイスループット細胞ベースのスクリーニングアッセイを利用する。マイクロタイタープレートのウェル中の多重化セルはユニークな実験のオプションでより高いスループットの可能性を提供しています。さらに、細胞のマイクロアレイのための現在の技術は飛躍的に生体内で 10,11 内から細胞の表現型を変える可能性がある細胞を乾燥させる。これらの問題を克服するために、MFCAは、操作された、 図1に示されている。MFCA 3次元流体工学の設計は、浴中に降下し、シールを形成する表面に対して圧縮されるように、図1のプリントヘッドチップを可能にする。プリントヘッドの柔らかいシリコーンチップは、同じように動作しガスケットと可逆的シールを形成する。 MFCA技術は、細胞培養物及び組織切片システムの両方に必要とされる浸漬表面とのインタフェースを一意に適しており、他のほとんどのアプローチでは困難又は不可能である。ピンやインクジェット印刷は機能しません、と2Dマイクロ流体デバイスは、蒸着やディスクリートスポットの大きな配列とのインタフェースに適していない。さらに、実験の小型化とローカル化することで - 携帯マイクロアレイを - MFCAは、ハイスループットの細胞ベースのスクリーニングアッセイに関連する主要な問題を克服する。 CFMは、表面12,13上の微小スポットの場所を介してサイクル少量流体サンプルに3Dチャンネルのネットワークを使用しています。流れに印刷することによって、生体分子、細胞、および他の試薬は、現在のセルの印刷技術を妨げる空気に曝すことなく敏感な生体分子および細胞の印刷を可能にする、印刷プロセス全体を通して液体環境に維持される。アレイ表面上の捕獲メカニズムが設けられ、このようなハイブリドーマまたは上清として粗物質から直接印刷することも可能である。本稿の目的は、表面上に詳細に2つの細胞型の浸漬印刷を説明することである。

<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>
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			<td height="21" style="height:21px;width:215px;"></td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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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.

線維芽細胞株NIH/3T3細胞を沈め表面に印刷又は播種した。細胞を、1ml当たり5×10 4細胞の密度まで増殖させた。細胞は、伝統的な細胞培養技術を用いて播種した。細胞は、大判、チャネルは、タンパク質および他の生体分子のために使用CFM以上（〜500μm）を大きい十二フローセルプリントヘッドを用いて印刷した。細胞は、血清コーティングされた表面に印刷または播種した。印刷処理...

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.

連続フローMicrospotterを使用して変更表面に細胞のサブマージ印刷

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

the-submerged-printing-cells-onto-modified-surface-using-continuous

Research

JoVE Journal

Bioengineering

8.6K ビュー.  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.

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

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.

導電性インクの平面および三次元印刷

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

生物工学

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.

層流のせん断応力下の内皮前駆細胞を評価するために、平行平板フローチャンバーと定常流回路

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 ...

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.

細胞の表面のガイダンスとBioprintingための自動ロボット調剤技術

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.

剪断応力の複数の平行平板流チャンバーを使用して内皮細胞の遺伝子発現解析

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.

マルチスペクトルイメージングフローサイトメトリーを用いてインビトロ微小核アッセイを行う自動化方法

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.

タイムラプス顕微鏡による 大腸菌 における生物学的ノイズの連続測定

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.

透過処理検出機能付き連続フローマイクロエレクトロポレーションシステムの構築と運用

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プリンティング技術を用いた血管フラップの作製

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

Automation of the Micronucleus Assay Using Imaging Flow Cytometry and Artificial Intelligence

The micronucleus (MN) assay is used worldwide by regulatory bodies to evaluate chemicals for genetic toxicity. The assay can be performed in two ways: by scoring MN in once-divided, cytokinesis-blocked binucleated cells or fully divided mononucleated cells. Historically, light microscopy has been the gold standard method to score the assay, but it is laborious and subjective. Flow cytometry has been used in recent years to score the assay, but is limited by the inability to visually confirm key aspects of cellular imagery. Imaging flow cytometry (IFC) combines high-throughput image capture and automated image analysis, and has been successfully applied to rapidly acquire imagery of and score all key events in the MN assay. Recently, it has been demonstrated that artificial intelligence (AI) methods based on convolutional neural networks can be used to score MN assay data acquired by IFC. This paper describes all steps to use AI software to create a deep learning model to score all key events and to apply this model to automatically score additional data. Results from the AI deep learning model compare well to manual microscopy, therefore enabling fully automated scoring of the MN assay by combining IFC and AI.

The micronucleus (MN) assay is a well-established test for quantifying DNA damage. However, scoring the assay using conventional techniques such as manual microscopy or feature-based image analysis is laborious and challenging. This paper describes the methodology to develop an artificial intelligence model to score the MN assay using imaging flow cytometry data.

イメージングフローサイトメトリーと人工知能を用いた小核アッセイの自動化

The micronucleus (MN) assay is used worldwide by regulatory bodies to evaluate chemicals for genetic toxicity. The assay can be performed in two ways: by ...

連続DLPプリンティングのためのバイオインク特性の定量的評価

Quantitative Characterization of Liquid Photosensitive Bioink Properties for Continuous Digital Light Processing Based Printing

Precise printing fabrication of bioinks is a prerequisite for tissue engineering; the Jacobs working curve is the tool to determine the precise printing parameters of digital light processing (DLP). However, the acquisition of working curves wastes materials and requires high formability of materials, which are not suitable for biomaterials. In addition, the reduction of cell activity due to multiple exposures and the failure of structural formation due to repeated positioning are both unavoidable problems in conventional DLP bioprinting. This work introduces a new method of obtaining the working curve and the improvement process of continuous DLP printing technology based on such a working curve. This method of obtaining the working curve is based on the absorbance and photorheological properties of the biomaterials, which do not depend on the formability of the biomaterials. The continuous DLP printing process, obtained from improving the printing process by analyzing the working curve, increases the printing efficiency more than tenfold and greatly improves the activity and functionality of cells, which is beneficial to the development of tissue engineering.

著者スポットライト:デジタル光処理ベースの連続印刷のための液体感光性バイオインク特性の定量的特性評価  

This study uses temperature and material composition to control the yield stress properties of yield stress fluids. The solid-like state of the ink can protect the printing structure, and the liquid-like state can continuously fill the printing position, realizing the digital light processing 3D printing of extremely soft bioinks.

連続デジタル光処理ベースの印刷のための液体感光性バイオインク特性の定量的特性評価

Precise printing fabrication of bioinks is a prerequisite for tissue engineering; the Jacobs working curve is the tool to determine the precise printing ...