この作品は、キュリー研究所、パリ、フランスで設立されました。機械式ストレッチャはダミアンCuvelier（キュリー研究所）によって設計され、GREM（メカニック-grem.com）によって製造されている。 PDMS上のパターニングはアマルAzioune（ボルドーII大学）によって開発されました。

1。 PDMSの不動態化<ol><li>あらかじめ作られたシート（材料の表に示すように、たとえば、GelPak、）からのX 20ミリメートルのPDMSが約35ミリメートルの部分をカット。 </li><li>プラスチックの上部と下部の保護層を除去（必要な場合）、ペトリ皿（処理した培養を細胞ではない）は、プラスチックに、PDMSを配置するためにピンセットを使用しています。 </li><li> /分30振動で回転装置上で5分間、70％エタノールで、PDMSを洗ってください。 </li><li>その上に空気を流すことにより、表面を乾燥させます。 </li><li>約5cmのUVバルブからの距離で5分間、深紫外（λ= 180 nm）をして点灯（ランプリファレンスのための材料のシートを参照してください。パラメータは、異なるランプに異なります）。 </li><li>各PDMSピース用EDC / NHS溶液200μlを準備し（溶液の反応性が時間のうちに崩壊するので、これは使用直前に調製しなければならない）。 pH6.0の0.05MのMES + 0.5 M NaCl緩衝液の1ミリリットルの場合は、スルホ-NHSの11.5 mgおよびEDCを19.2ミリグラムを追加します。 </li><li>転送照らされていないペトリ皿の蓋にペトリ皿からのPDMSシート。これはPDMSの周囲が非常に疎水性であることを確認して、次のステップを容易にするであろう。 </li><li> EDC / NHS溶液を添加し、室温で15分間インキュベートする。 </li><li>水とEDC / NHSを洗浄します。 </li><li> PLL-gの PEG-溶液（10mMのHEPES pHが8.6で0.5 mg / ml）を添加し、室温で一晩に3時間のインキュベート。 </li><li>水でPLL-G-PEGを洗浄します。 （PLL-gの -PEGで官能化された）不動態化されたPDMSは、4℃で数日間保存することができる</li></ol> 2。 PDMSのパターン化<ol><li> PDMSシートを取り、パターニング微小特徴を有する合成石英フォトマスクの上に置き（ 図1を参照）。フォトマスクのクロム側にPLL-G-PEGをもつPDMS側に配置します。 </li><li>約5cmのUVバルブから距離を置いて、フォトマスクを介して7分間点灯します。</li><li>マスク+ PDMS上に水を加え、徐々にマスクオフPDMSを剥離。 </li><li>室温で1時間、pH8.6のHEPESで緩衝液中に50 mg / mlのフィブロネクチン溶液でインキュベートする。それは、他のECMタンパク質を使用することが可能であるが、これらはこのプロトコルで試験されていない。 </li><li> PBSですすいでください。 </li></ol> 3。デバイスの取り付け<ol><li>ストレッチングデバイスに以前に不動態化されたPDMSをマウント（トラブルシューティングのための議論を参照）。 <ol><li>ストレッチャの固定部分にPDMSの1側を接続してください。 </li><li> PDMSシートのあまりをクランプすることなく、ストレッチャの可動部分に反対側を固定します。 </li></ol></li><li>厚手のPDMS刺しにPDMSの長方形（22ミリメートルX 19ミリメートル）をカットします（ 図2を参照）細胞および培地を保持し、プール（またはフレーム）を持つために内部に別の四角形を切った。 </li><li>この下にシリコーングリースを追加し、プールをPDMSおよびMEDを作成するために、PDMSシートの上部に配置しますイウムは、プールを保持。グリースは、延伸時のPDMSシート上のプールの滑空が可能になります。 </li></ol> 4。細胞のパターニング<ol><li>ベルセンと50％の集密度の培養フラスコから細胞を剥離。 </li><li>細胞を計数し、200,000細胞/ mlの濃度で再懸濁します。 </li><li> （詳細は、説明を参照）、プール内の細胞懸濁液の1ミリリットルを追加します。 </li><li>細胞が10〜30分間のパターンに結合する（細胞型に応じて、RPE-1細胞を20分間、10分間およびHeLa細胞がかかります）にしよう。 </li><li>静かに平衡化した培地（培養器内の媒質を平衡化）で浮遊細胞を洗い流す。 </li><li> （RPE-1は、少なくとも2時間が必要になります。HeLa細胞を3時間が必要になります）、細胞がパターンにはいくつかの時間のために普及してみよう。 </li><li> PDMSの改場合の蒸発とメディア漏れを回避するために、プールの上にカバースリップを追加します。 </li><li>倒立顕微鏡上のデバイスを入れて撮影開始。油浸OBの使用を避けるそれが原因で問題が焦点に動作しませんようにjectives。 </li></ol> 5。ストレッチング<ol><li> x軸、y軸、z軸（主にX）で​​のステージ位置を補正しながらマイクロメータネジを回します。ステージ位置は、PDMSの拡大、焦点の損失を打ち消すために補正する必要がある。 （議論では段落「ストレッチ中に」を参照してください）​​。 </li></ol>

<ol>
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Cell Biol. 10, 1401-1410 (2008).</li><li>Mitrossilis, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+single-cell+response+to+stiffness.">Real-time single-cell response to stiffness.</a> Proc. Natl. Acad. Sci. U.S.A. 107 (38), 16518-16523 (2010).</li><li>Irimia, D., Charras, G., Agrawal, N., Mitchison, T., Toner, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polar+stimulation+and+constrained+cell+migration+in+microfluidic+channels.">Polar stimulation and constrained cell migration in microfluidic channels.</a> Lab Chip. 12, 1783-1790 (2007).</li><li>Fink, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=External+forces+control+mitotic+spindle+positioning.">External forces control mitotic spindle positioning.</a> Nat. Cell. Biol. 13 (7), 771-778 (2011).</li><li>Azioune, A., Storch, M., Bornens, M., Th&#233;ry, M., Piel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+and+rapid+process+for+single+cell+micro-patterning.">Simple and rapid process for single cell micro-patterning.</a> Lab Chip. 9 (11), 1640-1642 (2009).</li><li>Azioune, A., Carpi, N., Tseng, Q., Th&#233;ry, M., Piel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+micropatterns:+A+direct+printing+protocol+using+deep+Uvs.">Protein micropatterns: A direct printing protocol using deep Uvs.</a> Methods Cell Biol. 97, 133-146 (2010).</li><li>Azioune, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robust+method+for+high-throughput+surface+patterning+of+deformable+substrates.">Robust method for high-throughput surface patterning of deformable substrates.</a> Langmuir. 27 (12), 7349-7352 (2011).</li><li>Carpi, N., Piel, M., Azioun, A., Cuvelier, D., Fink, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micropatterning+on+silicon+elastomer+(PDMS)+with+deep+UVs.">Micropatterning on silicon elastomer (PDMS) with deep UVs.</a> Protoc. Exch. , (2011).</li><li>Sinha, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cells+respond+to+mechanical+stress+by+rapid+disassembly+of+caveolae.">Cells respond to mechanical stress by rapid disassembly of caveolae.</a> Cell. 144 (3), 402-413 (2011).</li></ol>

著者らは、競合する経済的利益を宣言していません。

この技術は、多数回使用されていますし、徹底的にテストされていますが、失敗した実験につながることができ、いくつかの重要なステップがあります。 PDMSについて： この作業では、GelPak、市販の薄いPDMSシートを用いた。別の方法として、PDMSシートは、PDMSミックスから直接鋳造することができる。それは、より再現性があり、カスタムメイドのPDMS...

高等生物の組織を構成する細胞は、機械的緊張にさらされ、外部環境からか、周囲の細胞の1,2のいずれかから来る力を伸ばす。細胞は、に適応し、組織の完全性を維持するためにこれらの力に耐えなければならない。そのような力は、開発中に3,4の組織形態形成のためにも重要である。培養細胞に対する機械的な力を適用すると、組織内で何が起こるか模倣する方法ですが、細胞形状および細胞変形5,6の定量的かつ独立したコントロール機能を備えています。このために、いくつかの技術が使用されてもよい。一つは、AFMまたはその誘導体7,8を使用して、たとえば、細胞（全細胞またはその一部）に押したり、細胞が上に成長している基板を伸ばすことができます。 このホワイトペーパーで説明する方法は、細胞でメッキ面基板をストレッチする方法を示しています。この技術は、元々m個に作用する力の役割を評価するために開発されたitotic、哺乳動物細胞9。有糸分裂細胞は、引込みファイバを介して基板への接続を維持し、膜を延伸は今度は紡錘体の回転を引き起こし、これらの繊維に力を発揮した。接着マイクロパターンを組み合わせて、延伸の関心が力と個々の細胞の形状の独立した制御を達成することである。一軸延伸が適用されている間、それは、完全に等方性の丸い形状に卵形細胞を伸ばすために、例えば、可能である。細胞が微細にplattedされていない場合、ほとんどの細胞は一軸延伸軸と一致長軸を有する、細胞伸長における結果を延伸する。それは長い軸調整や細胞に適用し、ストレッチの効果の影響を分離することが、その後は難しい。 デバイスは、長い時間経過蛍光顕微鏡法を含む任意の生細胞イメージングのために適しており、薬物は、実験中に添加することができる。深いUVの用微細法10ら Aziouneに詳細に記載した。PDMS上11パターニングがAzioune らに記載された。12プロトコルを伸ばし存在カルピらのビデオ版です。13

<table><tbody><tr><td>GelPak</td><td>GelPak</td><td>PF-60-X4</td><td>Different thickness/stickiness are available. One alternative could be to cast your PDMS&amp;nbsp;yourself.</td></tr><tr><td>Silicon grease</td><td>GE Bayer Silicones</td><td>Baysilone-Paste</td><td>This one is biocompatible</td></tr><tr><td>Stretching device</td><td>GREM m&amp;eacute;canique</td><td>Stretcher 2011</td><td>&amp;nbsp;</td></tr><tr><td>EDC (N-(3-Dimethylaminopropyl)-N&amp;prime;-ethylcarbodiimide hydrochloride)</td><td>Sigma</td><td>3450</td><td>Stable 6 months at -20 &amp;deg;C</td></tr><tr><td>NHS (N-Hydroxysulfosuccinimide sodium salt)</td><td>Sigma</td><td>56485</td><td>Protect from humidity</td></tr><tr><td>Pll-g-peg (PLL(20)-g[3.5]-PEG(2) 20 mg)</td><td>SurfaceSolutions (Zurich)</td><td></td><td>&amp;nbsp;</td></tr><tr><td>Synthetic Quartz photomask</td><td>Toppan</td><td></td><td>Take standard binary photomask in Quartz</td></tr><tr><td>Fibronectin from bovine plasma</td><td>Sigma</td><td>F1141</td><td>&amp;nbsp;</td></tr></tbody></table>

stretching micropatterned cells on a pdms membrane

機械的力は、細胞に作用するおよび/または組織は、多くのプロセスにおいて重要な役割を果たしている。私たちは、イメージングと互換性ポリジメチルシロキサン（PDMS）膜上で平板培養した細胞を伸ばすためのデバイスを開発した。この手法は、再現性があり、汎用性があります。 PDMS膜は、特定の形状に細胞または組織を閉じ込めるために微細化することができる。最初のステップは、ディープUV技術とPDMS膜上に微細パターンを印刷することである。 PDMS膜は、次いで、機械的なストレッチャーに取り付けられている。室は、ストレッチの際に滑走できるように生体適合性グリース膜の上にバインドされています。細胞は播種し、微細パターン上の数時間広めるために許可されています。サンプルは、マイクロメータねじを用いて複数回延伸·未延伸することができる。それは、その全容（約30％）にストレッチを適用する分もかかります。ここで紹介するテクニックはために必要な電動式の装置が含まれていません迅速および/またはコンピュータ制御された延伸繰り返し延伸サイクルをpplyingが、これは実現することができる。細胞または組織の延伸は、細胞力、機械的なストレスや組織形態形成に対する細胞応答に関連した質問の対象となることができます。このビデオプレゼンテーションでは、一見シンプルなこのタイプの実験を行うときに発生する可能性のある一般的な問題を回避する方法を紹介します。

<html>このビデオプロトコルで提示技術は、有糸分裂、哺乳動物細胞の収縮繊維に力を加えることを可能にした。実際に、細胞分裂の間、有糸分裂の段階では、哺乳動物細胞は、球体の形状をとると、基板に取り付けられた膜で囲まれた細いアクチンケーブルを残すように後退させる。これらのケーブル（後退繊維）、除算に入る前にセル形状のメモリである。 PDMS薄膜上にフォトマスクを通?...

Watch this Scientific Journal Video about Stretching Micropatterned Cells on a PDMS Membrane at JoVE.com

Stretching Micropatterned Cells on a PDMS Membrane

この原稿は、単方向ストレッチを使用して接着細胞または組織に力を適用したり、解放する手法を提示します。

PDMS膜上のマイクロパターン細胞を伸ばす

Mechanical forces exerted on cells and/or tissues  play a major role in numerous processes. We have developed a device to stretch  cells plated on a ...

stretching-micropatterned-cells-on-a-pdms-membrane

Universidad de Cartagena UDEC

Research

JoVE Journal

Bioengineering

15.2K ビュー.  Institut Curie. この原稿は、単方向ストレッチを使用して接着細胞または組織に力を適用したり、解放する手法を提示します。 

ビデオ: Stretching Micropatterned Cells on a PDMS Membrane

Creating Two-Dimensional Patterned Substrates for Protein and Cell Confinement

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1 While microcontact printing can be employed to directly print a large number of molecules, including proteins,2 DNA,3 and silanes,4 the formation of self-assembled monolayers (SAMs) from long chain alkane thiols on gold provides a simple way to confine proteins and cells to specific patterns containing adhesive and resistant regions. This confinement can be used to control cell morphology and is useful for examining a variety of questions in protein and cell biology. Here, we describe a general method for the creation of well-defined protein patterns for cellular studies.5 This process involves three steps: the production of a patterned master using photolithography, the creation of a PDMS stamp, and microcontact printing of a gold-coated substrate. Once patterned, these cell culture substrates are capable of confining proteins and/or cells (primary cells or cell lines) to the pattern.
The use of self-assembled monolayer chemistry allows for precise control over the patterned protein/cell adhesive regions and non-adhesive regions; this cannot be achieved using direct protein stamping. Hexadecanethiol, the long chain alkane thiol used in the microcontact printing step, produces a hydrophobic surface that readily adsorbs protein from solution. The glycol-terminated thiol, used for backfilling the non-printed regions of the substrate, creates a monolayer that is resistant to protein adsorption and therefore cell growth.6 These thiol monomers produce highly structured monolayers that precisely define regions of the substrate that can support protein adsorption and cell growth. As a result, these substrates are useful for a wide variety of applications from the study of intercellular behavior7 to the creation of microelectronics.8
While other types of monolayer chemistry have been used for cell culture studies, including work from our group using trichlorosilanes to create patterns directly on glass substrates,9 patterned monolayers formed from alkane thiols on gold are straight-forward to prepare. Moreover, the monomers used for monolayer preparation are commercially available, stable, and do not require storage or handling under inert atmosphere. Patterned substrates prepared from alkane thiols can also be recycled and reused several times, maintaining cell confinement.10

Self-assembled monolayers (SAMs) formed from long chain alkane thiols on gold provide well-defined substrates for the formation of protein patterns and cell confinement. Microcontact printing of hexadecanethiol using a polydimethylsiloxane (PDMS) stamp followed by backfilling with a glycol-terminated alkane thiol monomer produces a pattern where protein and cells adsorb only to the stamped hexadecanethiol region.

タンパク質、細胞閉じ込めのための二次元加工基板を作成する

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1  While microcontact printing ...

生物工学

Stencil Micropatterning of Human Pluripotent Stem Cells for Probing Spatial Organization of Differentiation Fates

Human pluripotent stem cells (hPSCs), including embryonic stem cells and induced pluripotent stem cells, have the intrinsic ability to differentiate into all three germ layers. This makes them an attractive cell source for regenerative medicine and experimental modeling of normal and diseased organogenesis. However, the differentiation of hPSCs in vitro is heterogeneous and spatially disordered. Cell micropatterning technologies potentially offer the means to spatially control stem cell microenvironments and organize the resultant differentiation fates. Micropatterning hPSCs needs to take into account the stringent requirements for hPSC survival and maintenance. Here, we describe stencil micropatterning as a method that is highly compatible with hPSCs. hPSC micropatterns are specified by the geometries of the cell stencil through-holes, which physically confine the locations where hPSCs can access and attach to the underlying extracellular matrix-coated substrate. Due to this mode of operation, there is greater flexibility to use substrates that can adequately support hPSCs as compared to other cell micropatterning methods. We also highlight critical steps for the successful generation of hPSC micropatterns. As an example, we demonstrate that stencil micropatterning of hPSCs can be used to modulate spatial polarization of cell-cell and cell-matrix adhesions, which in turn determines mesoendoderm differentiation patterns. This simple and robust method to micropattern hPSCs widens the prospects of establishing experimental models to investigate tissue organization and patterning during early embryonic development.

Human pluripotent stem cells (hPSCs) have the intrinsic ability to differentiate and self-organize into distinct tissue patterns; although this requires the presentation of spatial environmental gradients. We present stencil micropatterning as a simple and robust method to generate biochemical and mechanical gradients for controlling hPSC differentiation patterns.

分化運命の空間組織を探るためのヒト多能性幹細胞のステンシルマイクロパターニング

Human pluripotent stem cells (hPSCs), including embryonic stem cells and induced pluripotent stem cells, have the intrinsic ability to differentiate into ...

発生生物学

A Novel Stretching Platform for Applications in Cell and Tissue Mechanobiology

Tools that allow the application of mechanical forces to cells and tissues or that can quantify the mechanical properties of biological tissues have contributed dramatically to the understanding of basic mechanobiology. These techniques have been extensively used to demonstrate how the onset and progression of various diseases are heavily influenced by mechanical cues. This article presents a multi-functional biaxial stretching (BAXS) platform that can either mechanically stimulate single cells or quantify the mechanical stiffness of tissues. The BAXS platform consists of four voice coil motors that can be controlled independently. Single cells can be cultured on a flexible substrate that can be attached to the motors allowing one to expose the cells to complex, dynamic, and spatially varying strain fields. Conversely, by incorporating a force load cell, one can also quantify the mechanical properties of primary tissues as they are exposed to deformation cycles. In both cases, a proper set of clamps must be designed and mounted to the BAXS platform motors in order to firmly hold the flexible substrate or the tissue of interest. The BAXS platform can be mounted on an inverted microscope to perform simultaneous transmitted light and/or fluorescence imaging to examine the structural or biochemical response of the sample during stretching experiments. This article provides experimental details of the design and usage of the BAXS platform and presents results for single cell and whole tissue studies. The BAXS platform was used to measure the deformation of nuclei in single mouse myoblast cells in response to substrate strain and to measure the stiffness of isolated mouse aortas. The BAXS platform is a versatile tool that can be combined with various optical microscopies in order to provide novel mechanobiological insights at the sub-cellular, cellular and whole tissue levels.

We present in this article a novel stretching platform that can be used to investigate single cell responses to complex anisotropic biaxial mechanical deformation and quantify the mechanical properties of biological tissues.

細胞および組織メカノでのアプリケーションのためのプラットフォームをストレッチ小説

Tools that allow the application of mechanical forces to cells and tissues or that can quantify the mechanical properties of biological tissues have ...

Expanding Nanopatterned Substrates Using Stitch Technique for Nanotopographical Modulation of Cell Behavior

Substrate nanotopography has been shown to be a potent modulator of cell phenotype and function. To dissect nanotopography modulation of cell behavior, a large area of nanopatterned substrate is desirable so that enough cells can be cultured on the nanotopography for subsequent biochemical and molecular biology analyses. However, current nanofabrication techniques have limitations to generate highly defined nanopatterns over a large area. Herein, we present a method to expand nanopatterned substrates from a small, highly defined nanopattern to a large area using stitch technique. The method combines multiple techniques, involving soft lithography to replicate poly(dimethylsiloxane) (PDMS) molds from a well-defined mold, stitch technique to assemble multiple PDMS molds to a single large mold, and nanoimprinting to generate a master mold on polystyrene (PS) substrates. With the PS master mold, we produce PDMS working substrates and demonstrate nanotopographical modulation of cell spreading. This method provides a simple, affordable yet versatile avenue to generate well-defined nanopatterns over large areas, and is potentially extended to create micro-/nanoscale devices with hybrid components.

A protocol for producing a large area of nanopatterned substrate from small nanopatterned molds for study of nanotopographical modulation of cell behavior is presented.

細胞の挙動のNanotopographical変調のステッチ法を用いたナノパターン基板を拡大

Substrate nanotopography has been shown to be a potent modulator of cell phenotype and function. To dissect nanotopography modulation of cell behavior, a ...

Patterning of Microorganisms and Microparticles through Sequential Capillarity-assisted Assembly

Controlled patterning of microorganisms into defined spatial arrangements offers unique possibilities for a broad range of biological applications, including studies of microbial physiology and interactions. At the simplest level, accurate spatial patterning of microorganisms would enable reliable, long-term imaging of large numbers of individual cells and transform the ability to quantitatively study distance-dependent microbe-microbe interactions. More uniquely, coupling accurate spatial patterning and full control over environmental conditions, as offered by microfluidic technology, would provide a powerful and versatile platform for single-cell studies in microbial ecology. 
This paper presents a microfluidic platform to produce versatile and user-defined patterns of microorganisms within a microfluidic channel, allowing complete optical access for long-term, high-throughput monitoring. This new microfluidic technology is based on capillarity-assisted particle assembly and exploits the capillary forces arising from the controlled motion of an evaporating suspension inside a microfluidic channel to deposit individual microsized objects in an array of traps microfabricated onto a polydimethylsiloxane (PDMS) substrate. Sequential depositions generate the desired spatial layout of single or multiple types of micro-sized objects, dictated solely by the geometry of the traps and the filling sequence. 
The platform has been calibrated using colloidal particles of different dimensions and materials: it has proven to be a powerful tool to generate diverse colloidal patterns and perform surface functionalization of trapped particles. Furthermore, the platform was tested on microbial cells, using Escherichia coli cells as a model bacterium. Thousands of individual cells were patterned on the surface, and their growth was monitored over time. In this platform, the coupling of single-cell deposition and microfluidic technology allows both geometric patterning of microorganisms and precise control of environmental conditions. It thus opens a window into the physiology of single microbes and the ecology of microbe-microbe interactions, as shown by preliminary experiments.

We present a technology that uses capillarity-assisted assembly in a microfluidic platform to pattern micro-sized objects suspended in a liquid, such as bacteria and colloids, into prescribed arrays on a polydimethylsiloxane substrate.

シーケンシャルキャピラリティーアシストアセンブリによる微生物と微粒子のパターニング

Controlled patterning of microorganisms into defined spatial arrangements offers unique possibilities for a broad range of biological applications, ...

工学

A Versatile Method of Patterning Proteins and Cells

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This article describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. This method enables researchers to pattern multiple substrates including fibronectin, collagen, antibodies (Sal-1), poly-D-lysine (PDL), and laminin. Patterning of substrates allows one to indirectly pattern a variety of cells. We have tested C2C12 myoblasts, the PC12 neuronal cell line, embryonic rat cortical neurons, and amphibian retinal neurons. In addition, we demonstrate that this technique can directly pattern fibroblasts in microfluidic channels via brief application of a low vacuum on cell suspensions. The low vacuum does not significantly decrease cell viability as shown by cell viability assays. Modifications are discussed for application of the method to different cell and substrate types. This technique allows researchers to pattern cells and proteins in specific patterns without the need for exotic materials or equipment and can be done in any laboratory with a vacuum.

This report describes a simple, easy to perform technique, using low pressure vacuum, to fill microfluidic channels with cells and substrates for biological research.

パターニングタンパク質および細胞の多彩な方法

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning ...

Preparation of Tunable Extracellular Matrix Microenvironments to Evaluate Schwann Cell Phenotype Specification

Traumatic peripheral nervous system (PNS) injuries currently lack suitable treatments to regain full functional recovery. Schwann cells (SCs), as the major glial cells of the PNS, play a vital role in promoting PNS regeneration by dedifferentiating into a regenerative cell phenotype following injury. However, the dedifferentiated state of SCs is challenging to maintain through the time-period needed for regeneration and is impacted by changes in the surrounding extracellular matrix (ECM). Therefore, determining the complex interplay between SCs and differing ECM to provide cues of regenerative potential of SCs is essential. To address this, a strategy was created where different ECM proteins were adsorbed onto a tunable polydimethylsiloxane (PDMS) substrate which provided a platform where stiffness and protein composition can be modulated. SCs were seeded onto the tunable substrates and critical cellular functions representing the dynamics of SC phenotype were measured. To illustrate the interplay between SC protein expression and cellular morphology, differing seeding densities of SCs in addition to individual microcontact printed cellular patterns were utilized and characterized by immunofluorescence staining and western blot. Results showed that cells with a smaller spreading area and higher extent of cellular elongation promoted higher levels of SC regenerative phenotypic markers. This methodology not only begins to unravel the significant relationship between the ECM and cellular function of SCs, but also provides guidelines for the future optimization of biomaterials in peripheral nerve repair.

This methodology aims to illustrate the mechanisms by which extracellular matrix cues such as substrate stiffness, protein composition and cell morphology regulate Schwann cell (SC) phenotype.

シュワン細胞表現型仕様を評価するための細胞外マトリックス微小環境の調製

Traumatic peripheral nervous system (PNS) injuries currently lack suitable treatments to regain full functional recovery. Schwann cells (SCs), as the ...

Control of Cell Geometry through Infrared Laser Assisted Micropatterning

Micropatterning is an established technique in the cell biology community used to study connections between the morphology and function of cellular compartments while circumventing complications arising from natural cell-to-cell variations. To standardize cell shape, cells are either confined in 3D molds or controlled for adhesive geometry through adhesive islands. However, traditional micropatterning techniques based on photolithography and deep UV etching heavily depend on clean rooms or specialized equipment. Here we present an infrared laser assisted micropatterning technique (microphotopatterning) modified from Doyle et al. that can be conveniently set up with commercially available imaging systems. In this protocol, we use a Nikon A1R MP+ imaging system to generate micropatterns with micron precision through an infrared (IR) laser that ablates preset regions on poly-vinyl alcohol coated coverslips. We employ a custom script to enable automated pattern fabrication with high efficiency and accuracy in systems not equipped with a hardware autofocus. We show that this IR laser assisted micropatterning (microphotopatterning) protocol results in defined patterns to which cells attach exclusively and take on the desired shape. Furthermore, data from a large number of cells can be averaged due to the standardization of cell shape. Patterns generated with this protocol, combined with high resolution imaging and quantitative analysis, can be used for relatively high throughput screens to identify molecular players mediating the link between form and function.

The protocol presented here enables automated fabrication of micropatterns that standardizes cell shape to study cytoskeletal structures within mammalian cells. This user-friendly technique can be set up with commercially available imaging systems and does not require specialized equipment inaccessible to standard cell biology laboratories.

赤外線レーザー支援マイクロパターンによる細胞形状の制御

Micropatterning is an established technique in the cell biology community used to study connections between the morphology and function of cellular ...

Pattern Generation for Micropattern Traction Microscopy

Micropattern traction microscopy allows control of the shape of single cells and cell clusters. Furthermore, the ability to pattern at the micrometer length scale allows the use of these patterned contact zones for the measurement of traction forces, as each micropatterned dot allows for the formation of a single focal adhesion that then deforms the soft, underlying hydrogel. This approach has been used for a wide range of cell types, including endothelial cells, smooth muscle cells, fibroblasts, platelets, and epithelial cells. 
This review describes the evolution of techniques that allow the printing of extracellular matrix proteins onto polyacrylamide hydrogels in a regular array of dots of prespecified size and spacing. As micrometer-scale patterns are difficult to directly print onto soft substrates, patterns are first generated on rigid glass coverslips that are then used to transfer the pattern to the hydrogel during gelation. First, the original microcontact printing approach to generate arrays of small dots on the coverslip is described. A second step that removes most of the pattern to leave islands of small dots is required to control the shapes of cells and cell clusters on such arrays of patterned dots. 
Next, an evolution of this approach that allows for the generation of islands of dots using a single subtractive patterning step is described. This approach is greatly simplified for the user but has the disadvantage of a decreased lifetime for the master mold needed to make the patterns. Finally, the computational approaches that have been developed for the analysis of images of displaced dots and subsequent cell-generated traction fields are described, and updated versions of these analysis packages are provided.

We describe improvements to a standard method for measuring cellular traction forces, based on microcontact printing with a single subtractive patterning step of dot arrays of extracellular matrix proteins on soft hydrogels. This method allows for simpler and more consistent fabrication of island patterns, essential for controlling cell cluster shape.

マイクロパターントラクション顕微鏡のパターン生成

Micropattern traction microscopy allows control of the shape of single cells and cell clusters. Furthermore, the ability to pattern at the micrometer ...

Generation of Multicue Cellular Microenvironments by UV-Photopatterning of Three-Dimensional Cell Culture Substrates

The extracellular matrix is an important regulator of cell function. Environmental cues existing in the cellular microenvironment, such as ligand distribution and tissue geometry, have been increasingly shown to play critical roles in governing cell phenotype and behavior. However, these environmental cues and their effects on cells are often studied separately using in vitro platforms that isolate individual cues, a strategy that heavily oversimplifies the complex in vivo situation of multiple cues. Engineering approaches can be particularly useful to bridge this gap, by developing experimental setups that capture the complexity of the in vivo microenvironment, yet retain the degree of precision and manipulability of in vitro systems.
This study highlights an approach combining ultraviolet (UV)-based protein patterning and lithography-based substrate microfabrication, which together enable high-throughput investigation into cell behaviors in multicue environments. By means of maskless UV-photopatterning, it is possible to create complex, adhesive protein distributions on three-dimensional (3D) cell culture substrates on chips that contain a variety of well-defined geometrical cues. The proposed technique can be employed for culture substrates made from different polymeric materials and combined with adhesive patterned areas of a broad range of proteins. With this approach, single cells, as well as monolayers, can be subjected to combinations of geometrical cues and contact guidance cues presented by the patterned substrates. Systematic research using combinations of chip materials, protein patterns, and cell types can thus provide fundamental insights into cellular responses to multicue environments.

Traditionally, cell culture is performed on planar substrates that poorly mimic the natural environment of cells in vivo. Here we describe a method to produce cell culture substrates with physiologically relevant curved geometries and micropatterned extracellular proteins, allowing systematic investigations into cellular sensing of these extracellular cues.