This work was funded by the National Science Foundation (CBET 0845754, AHH).

アルギン酸ディスクの形成のために1.準備<ol><li> 37℃の水浴中で添加し、塩化カルシウムまたは塩化マグネシウムと場所なしで1×ダルベッコのリン酸緩衝生理食塩水で4％（w / v）のアルギン酸塩溶液を調製します。 （w / v）のアルギン酸塩溶液が推奨されている4％ - アルギン酸塩溶液の濃度は様々であるが、1することができます。 </li><li>所望の細胞型のために暖かい細胞培養培地塩基（ 例えば 、ダルベッコ改変イーグル培地。）との1：1の割合でアルギン酸塩溶液を混ぜます。アルギン酸塩の濃度は、現在元の濃度の半分、 すなわち 、2％（W / V）。無菌の0.2μmのナイロンシリンジフィルターを用いて、アルギン酸塩/培地溶液を滅菌します。 </li><li> （ - 300ミリリットル〜200）を金型を沈めるために十分な溶液で滅菌水に無菌の102 mMの塩化カルシウム二水和物のバスを準備します。 </li><li>アルミ板で×3の3中の滅菌「ゲル形成型」（直径6mmのx 3ミリメートル背の高い円筒形の井戸を収集し、参照してください。 <strong&gt;図1）およびエンドプレート（下：1のアルミニウム板中のx 3の3、トップ：アルミ板で×3で1 1.5）と、次のように金型を準備します。 <ol><li>上部および下部終板のサイズに厚い濾紙（吸取濾紙）および細胞マイクロ篩膜（10ミクロン孔径）を切断し、飽和、約1分まで塩化カルシウム浴中に置き。所望の場合、使用前に30分間、オートクレーブまたは紫外光を介して厚い濾紙とマイクロシーブ膜を滅菌します。 </li><li>セットアップモールド構造体の半分（下半分）を。 <ol><li>次の順序で互いに上に以下の項目を配置し、滅菌スパチュラを用いて平滑化：大規模なエンドプレート、厚手のろ紙、その後、マイクロシーブ膜（3×3でで）。 </li><li>反転および過剰な塩化カルシウム溶液の損失を保証するために、ペーパータオルのスタックに金型を押してください。 </li><li> Cの上に円筒状のウェルを備えた「ゲル形成型」を配置しますエル膜をマイクロシーブ、静かに左右にバインダークリップを使用して、両側に一緒に金型を固定します。完全後で井戸をカバーするために（中×3で1.5）トップエンドプレートのための十分な余地を残していることを確認してください。 </li></ol></li><li>セットアップモールド構造体の後半（上半分）を。 <ol><li>次の順序で互いに上に以下の項目を配置し、円滑：小端板、厚手のろ紙、マイクロシーブ膜。 </li><li>過剰の塩化カルシウム溶液の損失を保証するために、ペーパータオルのスタック上に金型のこの半分を反転し、押します。この時点でバインダークリップを使用して、金型のこの半分を固定しないでください。 </li></ol></li></ol></li><li>培養細胞は、製造業者の指示に従ってお勧めします。層状のアルギン酸ハイドロゲルに埋め込むべき所望の細胞を採取します。推奨される細胞密度は1 - 2×10 6細胞/ mlで、これは、所望の実験に応じて変化させることができます。 注：この方法を使用する場合異なる細胞型を有する層を作製するために、重ね着に並列に文化2つの細胞型に確認してください。 （MSCS）は、1×10 6細胞/ mlの細胞密度で播種した間葉系幹細胞は、以下のプロトコルのための例として使用されます。必要に応じて、細胞数とディスク番号が実験のためにスケーリングすることができます。 <ol><li>基礎成長培地10mlの（ダルベッコ改変イーグル培地、10％ウシ胎児血清、2％L-グルタミン、1で5,000細胞/ cm 2 - 1〜2週間前に3,000の細胞密度で、種間葉系幹細胞を包埋しますT-75フラスコ中の％非必須アミノ酸、1％ペニシリン/ストレプトマイシン）。 </li><li> 3日後、細胞が80になるまで、基礎増殖培地10mlで置き換える - - すべての2使用済みメディアを取り出し、90％のコンフルエント。 </li><li>収穫細胞に、細胞をすすぐために使用済み培地、および追加された塩化カルシウムや塩化マグネシウムなしの1×ダルベッコのリン酸緩衝生理食塩水のピペット3ミリリットルを削除します。ピペット、0.25％の試行の3ミリリットルをこのソリューションを削除しますT-75フラスコ中で増殖している細胞へPSIN-EDTA、および37℃で5分間インキュベートします。基礎成長培地の9ミリリットル - 細胞が付着面から持ち上げた後、6を追加します。 </li><li>遠心機MSCは、室温で5分間、600×gで、上清を吸引し、そして1に再懸濁 - 基礎成長培地5mlの。デバイス命令を使用して、血球計数器を用いて細胞を数えます。 </li><li>同じ条件を用いて、全細胞の再懸濁、遠心機から1×10 6細胞を除去し、上清を吸引除去します。 </li></ol></li></ol>セルシードアルギン酸ディスクの2形成<ol><li> 1×10 6細胞/ mlの細胞密度を達成するために、滅菌アルギネート/培地溶液1mlで細胞ペレットを再懸濁します。細胞が適切に混在している場合、細胞 - アルギン酸塩の混合物は、外観が均一に曇っなります。 </li><li>ピペット金型の下半分の6つの直径6mmのx 3ミリメートル背の高いウェルに細胞 - アルギン酸塩の混合物130μlの気泡を作成しないように、滴下して構築します。わずかな凸状メニスカスは、各ウェルの縁上記表示されるはずです。 </li><li>慎重に滅菌スパチュラを用いて、金型構造体の上半分を滑らかと細胞マイクロシーブ膜が井戸の上になるように、それを裏返します。完全セルとアルギン酸塩の混合物を含むウェルをカバーするのに確認して、井戸の上にモールド構造体を配置します。 </li><li>中央をしっかり押しながら、ロードされたモールド構造体を持ち上げて、バインダーは、モールド構造体の上部と下部の半分を固定するために、残りの二辺（上部と下部）をクリップします。細胞アルギン酸ソリューションは確実にこの時点でウェルに囲まれるべきです。 </li><li>構築物全体が水没していることを確認して、102 mMの塩化カルシウム浴中の固定金型構造体を浸し。 90分間室温で細胞培養フード中でインキュベートします。 </li><li> 90分の終わりに、102 mMの塩化カルシウムからモールド構造体を除去します細胞培養フード内ペーパータオルのスタック上の風呂と場所。すべての4つのバインダークリップを外し、金型構造体の2つの半分を分けます。ウェル内に形成されたヒドロゲルは、任意の気泡を持つべきではないと完全に井戸を埋める必要があります。 </li><li>へらを使用して、慎重に慎重に緩め、ヒドロゲルをウェッジハイドロゲルを含むウェルの縁をたどります。金型構築物からヒドロゲルを除去した後、塩化カルシウムおよび塩化マグネシウムと1×ダルベッコのリン酸緩衝生理食塩水の槽に直接ヒドロゲルをドロップします。 5分 - 1のための過剰な塩化カルシウム溶液を洗い流し、完全にゲルをカバーしています。 </li><li>完全にハイドロゲルをカバーする目的の皿の中の基礎増殖培地溶液（ 例えば 、6ウェルプレート）にヒドロゲルを転送します。積層工程に進む前に、37℃で細胞培養インキュベーター中で少なくとも1時間、5％CO 2インキュベートします。 注：細胞を含むヒドロゲルを中に保持することができます3日 - 別の細胞集団とゲルの積層までこの時無期限細胞培養インキュベーターは、メディアの変更はすべて2完了したことを条件とする、望ましいです。 </li></ol>アルギン酸ディスクの3層化<ol><li> 1時間のインキュベーションの最後の半分の時間の間に、ゲルをアニールするための無菌金型やソリューションを収集し、準備します。 <ol><li> x方向（エンドプレートに3（アルミ板に×3の3で、直径6mmのx 1.5ミリメートル背の高い井戸） &quot;ゲル形成型」の高さのウェルの半分を持っている金型を固定することにより、「切断金型を&quot;準備左右にバインダークリップを使用してアルミニウム板3）。 </li><li> X 3（終板に「ゲル形成型」よりも直径が3ミリメートル大きい金型を固定することにより、「アニーリング金型」（9ミリメートルの直径のx 3ミリメートルのアルミニウム板中のx 3の3で背の高い井戸）を準備左右にバインダークリップを使用してアルミニウム板3）。 </li><li>の溶液を準備します100mMの滅菌水にクエン​​酸ナトリウム/ 30mMのEDTA（クエン酸ナトリウム二水和物、エチレンジアミン四酢酸四ナトリウム塩二水和物）。 </li></ol></li><li>皿にメディアから（この例では、hMSCを持つ2つのディスク）所望の細胞集団のゲルを外し、「切断金型」ウェルに配置します。各ゲルは、金型の上に突出したゲルの半分でウェルにぴったりとフィットする必要があります。 </li><li>メスを用いて、（これは半分にヒドロゲルを削減する）金型の表面に沿ってゲルスライス。ゲルの上半分を反転し、開放金型のウェルに配置します。ゲルの半分もよく、金型にぴったりとフィットする必要がありますが、今、両方の半ゲルは、可視カット内面に金型の高さでなければなりません。第二のゲルで繰り返します。 注：警告：のみ内側の切断面は、層状のディスクを形成することになります。外表面を使用して分離半分になります。これは、ゲル表面防止に転写マイクロシーブ膜からそのテクスチャを疑われますアニール処理の成功。 </li><li>マイクロシーブ膜をアニールするゲルの半分の全てに接触していることを確認すると、それらを完全にカバーし、井戸の上に乾電池マイクロシーブ膜のピースを置きます。完全にゲルをカバーすることを確認して、マイクロシーブ膜の上に厚手のろ紙を置きます。 </li><li>それが飽和するまでの厚さの濾紙上に100mMのクエン酸ナトリウム/ 30mMのEDTA（クエン酸ナトリウム二水和物、エチレンジアミン四酢酸四ナトリウム塩二水和物）の溶液をピペット。約750μlの4つのウェルのために十分です。 </li><li>室温で1分間ゲルをインキュベートします。その後、細胞マイクロ篩膜と厚いろ紙を削除し、それらを捨てます。バインダークリップを外し、金型を開きます。 </li><li>各アニールゲルについて、切断面を上に​​向けて準備された「アニーリング金型」にヒドロゲルの1クエン酸ナトリウム/ EDTA処理の半分を転送します。これは、アニール定数の半分になりますruct。 </li><li>切断面が入っているように、この第2の半ゲルを反転、既に「アニーリング型」のゲル上に（異なる細胞型を含んでいてもよい）へら、リフトを使用し、第二クエン酸ナトリウム/ EDTA処理した半ゲルを配置「アニーリング型」で既にゲルの切断面に接触します。 </li><li>そっと2つのゲルの間の任意の気泡を除去するためにスパチュラを用いて2つのゲルを押し。また、必要に応じて、彼らは互いの上に直接あることを確認するために、ゲルを再配置します。 </li><li>穏やかに「アニール型」を持ち上げ、30分間、102 mMの塩化カルシウム浴中に沈めます。エンドプレートでウェルをカバーしないでください。 </li><li> 30分のインキュベーションの後、「アニーリングモールド」を削除し、ペーパータオルの上に置きます。バインダークリップを外し、エンドプレートからモールドを分離します。 </li><li>スパチュラを用いて、アニールゲルを収集し、塩化カルシウムおよびmは1×ダルベッコのリン酸緩衝生理食塩水に入れますagnesium塩化物浴は、ゲルを洗浄します。続いて、転送は、培養のための所望のディッシュ（ 例えば 、6ウェルプレート）で細胞培養培地にヒドロゲルをアニール。 </li></ol>

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The authors have nothing to disclose.

ここでは、軟骨、例えば 、生理学的に層状の組織のものなど、複数の細胞集団の共培養を、研究するための層状のアルギン酸ハイドロゲルディスクを形成するためのプロトコルについて説明します。そのような記載培養プラットフォームとしての層状構造は、同一の培養環境や負荷の下で施す二つの異なる細胞集団との間の相互作用を調べるために使用することができます。 <p clas...

このような関節軟骨や椎間板などの圧縮荷重支持組織は、組織の両方の生体力学的機能と適切なメカノトランスダクションのために重要である異種の組織領域で構成されています。だけでなく、細胞組織化され、さまざまな地域での異なる機能が、細胞外マトリックス（ECM）は、組成や組織に変化しています。例えば、関節軟骨は、細胞の形態、機械的機能、およびECMを変えて3プライマリゾーンで構成されています。耐荷重の責任を差動に自分のECMリードの違い。真ん中の深いゾーンは圧縮1への応答のために主に責任がありながら、表層は、主に、ロードするために引張応答に関与しています。同様に、椎間板に、ゲル状の髄核は、ラメラ線維輪に囲まれており、これらの二つの異なる領域内の細胞は、生物物理学的刺激の異なる種類を体験されています組織が ​​受けると、機械的な力に応答するように2組織層内の組織、細胞と細胞外マトリックスのこれらのタイプでは、互いに相互作用します。 このような不均質な組織構造の要約は、組織工学および再生医療における課題のままであり、その生物学的意義の理解は限られています。層状組織ならびに1つの構築物内の細胞の異なる集団の共培養物を分析するためのプラットフォームを培養する必要があります。関節軟骨組織工学では、足場レス層状構築物は、この組織3,4の異なる層を模倣するために様々なECMを堆積する帯状の軟骨細胞の能力を活用することによって構築されてきました。しかしながら、層状ヒドロゲル構築物は、独立して、強固な組織を形成する能力を欠いている細胞集団の多様な種類の相互作用を調査するための機会を提供します。例えば、異なるポップ間葉系幹細胞のulations層状のコンストラクト内で共培養することができます。このような層状足場は、軟骨細胞および改善された組織工学5のための間葉系幹細胞を分化の両方で使用されてきました。異なる細胞集団は、類似のハイドロゲル層に共培養することができるが、単一の細胞型は、細胞6,7から異なる応答を誘発するために剛性または生化学的なコンテンツを変化しているために操作された層内に培養することができる。のみならず多くの異なる生体材料のヒドロゲルは、ポリエチレングリコール又はポリビニルアルコールベース7-9を使用するもののような軟骨組織工学のための細胞集団の層に使用されてきました。しかし、アルギン酸ハイドロゲルは、共培養に不均一な細胞集団を研究するための層状の足場を作成するための最も簡単な生体材料の一つです。アガロースハイドロゲルも容易に形成されているが、アルギン酸ハイドロゲルは容易であることが可能という利点を持っています個々の細胞の分析のために3-D構築物からの細胞のオレーション以前10に記載されているように。以前の研究では、二層アルギン酸ハイドロゲルは、薄いシートに形成されており、これらのシートから、セクションでは、スライスした（ 例えば 、生検パンチを使用して）、そのような生化学的コンテンツや界面剪断特性11,12の分析のためのような特定のアプリケーションのために。薄いアルギネートシートを形成するための別の方法は、複数の層に層別化の可能性と説明したが、依然として機械的試験13に使用するためのヒドロゲルの変更を必要とするであろう。 ここでは、再現性の細胞の異なる集団を共培養に使用するための二層アルギン酸ヒドロゲルのディスクを作成するための方法を提示します。このアルギン酸ディスク・プラットフォームは、いくつかの利点を有しています。主に、再現可能な形状とサイズが小さい生検PUを必要とせずに埋め込まれた細胞の機械的刺激のために助長していますNCH​​や多くのアプリケーションのためのヒドロゲルに他の物理的変化。さらに、細胞生存率は、積層プロセス中に高いままであり、ゲル形成後のゲル内の2つの細胞集団の明確な分離はありません最初のオーバーラップ領域で表示されます。

<table><tbody><tr><td>Alginic Acid sodium salt</td><td>Sigma Aldrich</td><td>A1112</td><td>Solution made in wt% using DPBS (-/-)</td></tr><tr><td>1x Dulbecco&#039;s Phosphate Buffered Saline (-/-)</td><td>Gibco Life Technologies&amp;nbsp;</td><td>14190</td><td></td></tr><tr><td>1x Dulbecco&#039;s Phosphate Buffered Saline (+/+)</td><td>Gibco Life Technologies&amp;nbsp;</td><td>14190</td><td></td></tr><tr><td>Dulbecco&#039;s Modified Eagle Medium</td><td>Gibco Life Technologies&amp;nbsp;</td><td>11965</td><td>Example. Use desired medium type</td></tr><tr><td>Syringe Filters (0.02 &amp;#956;m Nylon)</td><td>FisherBrand</td><td>0979C</td><td></td></tr><tr><td>Calcium Chloride Dihydrate</td><td>Fisher Bioreagents</td><td>BP510</td><td>Prepare solution in sterile water</td></tr><tr><td>Criterion Blotter Filter Paper</td><td>Biorad</td><td>1704085</td><td>Cut to size of endplates for mold formation</td></tr><tr><td>Cell Microsieve Membrane (10 &amp;#956;m pore size)</td><td>Biodesign Inc of New York</td><td>N10R</td><td>Cut to size of endplates for mold formation</td></tr><tr><td>Sodium citrate dihydrate</td><td>FisherScience</td><td>S93364</td><td></td></tr><tr><td>Ethylenediaminetetraacetic acid tetrasodium salt dihydrate (EDTA)</td><td>FisherBioreagent</td><td>BP121</td><td></td></tr><tr><td>Fetal Bovine Serum&amp;nbsp;</td><td>Gibco Life Technologies&amp;nbsp;</td><td>26140</td><td>Used in example mesenchymal stem cell basal growth media</td></tr><tr><td>Penicilin/Streptomycin (10,000 U/ml)</td><td>Gibco Life Technologies&amp;nbsp;</td><td>15140</td><td>Used in example mesenchymal stem cell basal growth media</td></tr><tr><td>L-Glutamine (200 mM)</td><td>Gibco Life Technologies&amp;nbsp;</td><td>25030081</td><td>Used in example mesenchymal stem cell basal growth media</td></tr><tr><td>Non-essential Amino Acids (100x)</td><td>Gibco Life Technologies&amp;nbsp;</td><td>11140050</td><td>Used in example mesenchymal stem cell basal growth media</td></tr></tbody></table>

layered alginate constructs: a platform for co-culture of heterogeneous cell populations

Many load bearing tissues possess structurally and functionally distinct regions, typically accompanied by different cell phenotypes with differential mechanosensing characteristics. Engineering and analysis of these tissue types remain a challenge. Layered hydrogel constructs provide an opportunity for investigating the interactions among multiple cell populations within single constructs. Alginate hydrogels are both biocompatible and allow for easy isolation of cells after experimentation. Here, we describe a method for the development of small sized dual layered alginate hydrogel discs. This process maintains high cell viability of human mesenchymal stem cells during the formation process and these layered discs can withstand unconfined cyclic compression, commonly used for stimulation of hMSCs undergoing chondrogenesis. These layered constructs can potentially be scaled up to include additional levels, and also be used to segregate cell populations initially after layering. This dual layer alginate hydrogel culture platform can be used for many different applications including engineering and analysis of cells of load bearing tissues and co-cultures of other cell types.

図1は、アルギン酸塩ヒドロゲルの形成と階層化を示しています。 図2に示すように、完成した二層状ゲルは、細胞集団の完全な初期の分離を示す。ヒト間葉系幹細胞の細胞生存率）をこれらのヒドロゲル内に埋め込 ​​まれ、層状、図3に示すように、バルクのヒドロゲル高と同等のままである。生存率を評価しました。アニー?...

Watch this Scientific Journal Video about Layered Alginate Constructs: A Platform for Co-culture of Heterogeneous Cell Populations at JoVE.com

Layered Alginate Constructs: A Platform for Co-culture of Heterogeneous Cell Populations

Engineering and analysis of load bearing tissues with heterogeneous cell populations are still a challenge. Here, we describe a method for creating bi-layered alginate hydrogel discs as a platform for co-culture of diverse cell populations within one construct.

階層化アルギン酸構築：異種細胞集団の共培養のためのプラットフォーム

Many load bearing tissues possess structurally and functionally distinct regions, typically accompanied by different cell phenotypes with differential ...

layered-alginate-constructs-platform-for-co-culture-heterogeneous

Universidad de Cartagena UDEC

Research

JoVE Journal

Bioengineering

7.8K ビュー.  University of Maryland. Engineering and analysis of load bearing tissues with heterogeneous cell populations are still a challenge. Here, we describe a method for creating bi-layered alginate hydrogel discs as a platform for co-culture of diverse cell populations within one construct. 

ビデオ: Layered Alginate Constructs: A Platform for Co-culture of Heterogeneous Cell Populations

Microfabricated Platforms for Mechanically Dynamic Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

機械的にダイナミックな細胞培養のための微細加工プラットフォーム

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or ...

生物工学

Alginate Hydrogels for Three-Dimensional Organ Culture of Ovaries and Oviducts

Ovarian cancer is the fifth leading cause of cancer deaths in women and has a 63% mortality rate in the United States1. The cell type of origin for ovarian cancers is still in question and might be either the ovarian surface epithelium (OSE) or the distal epithelium of the fallopian tube fimbriae2,3. Culturing the normal cells as a primary culture in vitro will enable scientists to model specific changes that might lead to ovarian cancer in the distinct epithelium, thereby definitively determining the cell type of origin. This will allow development of more accurate biomarkers, animal models with tissue-specific gene changes, and better prevention strategies targeted to this disease.
Maintaining normal cells in alginate hydrogels promotes short term in vitro culture of cells in their three-dimensional context and permits introduction of plasmid DNA, siRNA, and small molecules. By culturing organs in pieces that are derived from strategic cuts using a scalpel, several cultures from a single organ can be generated, increasing the number of experiments from a single animal. These cuts model aspects of ovulation leading to proliferation of the OSE, which is associated with ovarian cancer formation. Cell types such as the OSE that do not grow well on plastic surfaces can be cultured using this method and facilitate investigation into normal cellular processes or the earliest events in cancer formation4.
Alginate hydrogels can be used to support the growth of many types of tissues5. Alginate is a linear polysaccharide composed of repeating units of &beta;-D-mannuronic acid and &alpha;-L-guluronic acid that can be crosslinked with calcium ions, resulting in a gentle gelling action that does not damage tissues6,7. Like other three-dimensional cell culture matrices such as Matrigel, alginate provides mechanical support for tissues; however, proteins are not reactive with the alginate matrix, and therefore alginate functions as a synthetic extracellular matrix that does not initiate cell signaling5. The alginate hydrogel floats in standard cell culture medium and supports the architecture of the tissue growth in vitro.
A method is presented for the preparation, separation, and embedding of ovarian and oviductal organ pieces into alginate hydrogels, which can be maintained in culture for up to two weeks. The enzymatic release of cells for analysis of proteins and RNA samples from the organ culture is also described. Finally, the growth of primary cell types is possible without genetic immortalization from mice and permits investigators to use knockout and transgenic mice.

Culture of normal cells in their three-dimensional context represents an alternative method to study early events required for cellular transformation and tumorigenesis. This method is used to grow normal ovarian and oviductal cells to study early events in ovarian cancer formation.

卵巣と卵管の三次元器官培養用アルギン酸ゲル

Ovarian cancer is the fifth leading cause of cancer deaths in women and has a 63% mortality rate in the United States1. The cell type of origin for ...

Alginate Encapsulation of Pluripotent Stem Cells Using a Co-axial Nozzle

Pluripotent stem cells (PS cells) are the focus of intense research due to their role in regenerative medicine and drug screening. However, the development of a mass culture system would be required for using PS cells in these applications. Suspension culture is one promising culture method for the mass production of PS cells, although some issues such as controlling aggregation and limiting shear stress from the culture medium are still unsolved. In order to solve these problems, we developed a method of calcium alginate (Alg-Ca) encapsulation using a co-axial nozzle. This method can control the size of the capsules easily by co-flowing N2 gas. The controllable capsule diameter must be larger than 500 &#181;m because too high a flow rate of N2 gas causes the breakdown of droplets and thus heterogeneous-sized capsules. Moreover, a low concentration of Alg-Na and CaCl2 causes non-spherical capsules. Although an Alg-Ca capsule without a coating of Alg-PLL easily dissolves enabling the collection of cells, they can also potentially leak out from capsules lacking an Alg-PLL coating. Indeed, an alginate-PLL coating can prevent cellular leakage but is also hard to break. This technology can be used to research the stem cell niche as well as the mass production of PS cells because encapsulation can modify the micro-environment surrounding cells including the extracellular matrix and the concentration of secreted factors.

We established a method of encapsulating pluripotent stem cells (PS cells) into alginate hydrogel capsules using a co-axial nozzle. This prevents cells from aggregating excessively and limits the shear stress experienced by cells in suspension culture. The technique is applicable to the mass production of PS cells as well as research on stem cell niche.

同軸ノズルを用いて多能性幹細胞のアルギン酸カプセル化

Pluripotent stem cells (PS cells) are the focus of intense research due to their role in regenerative medicine and drug screening.  However, the ...

発生生物学

Generation of Alginate Microspheres for Biomedical Applications

Alginate-based materials have received considerable attention for biomedical applications because of their hydrophilic nature, biocompatibility, and physical architecture. Applications include cell encapsulation, drug delivery, stem cell culture, and tissue engineering scaffolds. In fact, clinical trials are currently being performed in which islets are encapsulated in PLO coated alginate microbeads as a treatment of type I diabetes. However, large numbers of islets are required for efficacy due to poor survival following transplantation. The ability to locally stimulate microvascular network formation around the encapsulated cells may increase their viability through improved transport of oxygen, glucose and other vital nutrients. Fibroblast growth factor-1 (FGF-1) is a naturally occurring growth factor that is able to stimulate blood vessel formation and improve oxygen levels in ischemic tissues. The efficacy of FGF-1 is enhanced when it is delivered in a sustained fashion rather than a single large-bolus administration. The local long-term release of growth factors from islet encapsulation systems could stimulate the growth of blood vessels directly towards the transplanted cells, potentially improving functional graft outcomes. In this article, we outline procedures for the preparation of alginate microspheres for use in biomedical applications. In addition, we describe a method we developed for generating multilayered alginate microbeads. Cells can be encapsulated in the inner alginate core, and angiogenic proteins in the outer alginate layer. The release of proteins from this outer layer would stimulate the formation of local microvascular networks directly towards the transplanted islets.

In the following sections, we outline procedures for the preparation of alginate microspheres for use in biomedical applications. We specifically illustrate a technique for creating multilayered alginate microspheres for the dual purpose of cell and protein encapsulation as a potential treatment for type 1 diabetes.

バイオメディカル応用のためのアルギン酸ミクロスフェアの生成

Alginate-based materials have received considerable attention for biomedical applications because of their hydrophilic nature, biocompatibility, and ...

医学

Cell Co-culture Patterning Using Aqueous Two-phase Systems

Cell patterning technologies that are fast, easy to use and affordable will be required for the future development of high throughput cell assays, platforms for studying cell-cell interactions and tissue engineered systems. This detailed protocol describes a method for generating co-cultures of cells using biocompatible solutions of dextran (DEX) and polyethylene glycol (PEG) that phase-separate when combined above threshold concentrations. Cells can be patterned in a variety of configurations using this method. Cell exclusion patterning can be performed by printing droplets of DEX on a substrate and covering them with a solution of PEG containing cells. The interfacial tension formed between the two polymer solutions causes cells to fall around the outside of the DEX droplet and form a circular clearing that can be used for migration assays. Cell islands can be patterned by dispensing a cell-rich DEX phase into a PEG solution or by covering the DEX droplet with a solution of PEG. Co-cultures can be formed directly by combining cell exclusion with DEX island patterning. These methods are compatible with a variety of liquid handling approaches, including manual micropipetting, and can be used with virtually any adherent cell type.

Aqueous two-phase systems were used to simultaneously pattern multiple populations of cells. This fast and easy method for cell patterning takes advantage of the phase separation of aqueous solutions of dextran and polyethylene glycol and the interfacial tension that exists between the two polymer solutions.

水性二相系を用いた細胞の共培養パターニング

Cell patterning  technologies that are fast, easy to use and affordable will be required for the  future development of high throughput cell assays, ...

Construction of Modular Hydrogel Sheets for Micropatterned Macro-scaled 3D Cellular Architecture

Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue geometry. The resulting 3D hydrogel-based cellular constructs have been introduced as an alternative to animal experiments for advanced biological studies, pharmacological assays and organ transplant applications. Although hydrogel-based particles and fibers can be easily fabricated, it is difficult to manipulate them for tissue reconstruction. In this video, we describe a fabrication method for micropatterned alginate hydrogel sheets, together with their assembly to form a macro-scale 3D cell culture system with a controlled cellular microenvironment. Using a mist form of the calcium gelling agent, thin hydrogel sheets are easily generated with a thickness in the range of 100 - 200 &#181;m, and with precise micropatterns. Cells can then be cultured with the geometric guidance of the hydrogel sheets in freestanding conditions. Furthermore, the hydrogel sheets can be readily manipulated using a micropipette with an end-cut tip, and can be assembled into multi-layered structures by stacking them using a patterned polydimethylsiloxane (PDMS) frame. These modular hydrogel sheets, which can be fabricated using a facile process, have potential applications of in vitro drug assays and biological studies, including functional studies of micro- and macrostructure and tissue reconstruction.

We describe the fabrication of micropatterned hydrogel sheets using a simple process, which can be assembled and manipulated in a freestanding form. Using these modular hydrogel sheets, a simple macro-scaled 3D cell culture system can be generated with a controlled cellular microenvironment.

マイクロパターンマクロスケール3D細胞構造のためのモジュラーヒドロゲルシートの構築

Hydrogels can be patterned at the micro-scale using microfluidic or micropatterning technologies to provide an in vivo-like three-dimensional (3D) tissue ...

Ultrathin Porated Elastic Hydrogels As a Biomimetic Basement Membrane for Dual Cell Culture

The basement membrane is a critical component of cellular bilayers that can vary in stiffness, composition, architecture, and porosity. In vitro studies of endothelial-epithelial bilayers have traditionally relied on permeable support models that enable bilayer culture, but permeable supports are limited in their ability to replicate the diversity of human basement membranes. In contrast, hydrogel models that require chemical synthesis are highly tunable and allow for modifications of both the material stiffness and the biochemical composition via incorporation of biomimetic peptides or proteins. However, traditional hydrogel models are limited in functionality because they lack pores for cell-cell contacts and functional in vitro migration studies. Additionally, due to the thickness of traditional hydrogels, incorporation of pores that span the entire thickness of hydrogels has been challenging. In the present study, we use poly-(ethylene-glycol) (PEG) hydrogels and a novel zinc oxide templating method to address the previous shortcomings of biomimetic hydrogels. As a result, we present an ultrathin, basement membrane-like hydrogel that permits the culture of confluent cellular bilayers on a customizable scaffold with variable pore architectures, mechanical properties, and biochemical composition.

Current bilayer culture models do not allow for functional in vitro studies that mimic in vivo microenvironments. Using polyethylene glycol and a zinc oxide templating method, this protocol describes the development of an ultrathin biomimetic basement membrane with tunable stiffness, porosity, and biochemical composition that closely mimics in vivo extracellular matrices.

デュアルのバイオミメティック基底膜として極薄 Porated 弾性ゲルの細胞培養

The basement membrane is a critical component of cellular bilayers that can vary in stiffness, composition, architecture, and porosity. In vitro studies ...

Three-dimensional Alginate-bead Culture of Human Pituitary Adenoma Cells

A three-dimensional culture method is described in which primary pituitary adenoma cells are grown in alginate beads. Alginate is a polymer derived from brown sea algae. Briefly, the tumor tissue is cut into small pieces and submitted to an enzymatic digestion with collagenase and trypsin. Next, a cell suspension is obtained. The tumor cell suspension is mixed with 1.2% sodium alginate and dropped into a CaCl2 solution, and the alginate/cell suspension is gelled on contact with the CaCl2 to form spherical beads. The cells embedded in the alginate beads are supplied with nutrients provided by the culture media enriched with 20% FBS. Three-dimensional culture in alginate beads maintains the viability of adenoma cells for long periods of time, up to four months. Moreover, the cells can be liberated from the alginate by washing the beads with sodium citrate and seeded on glass coverslips for further immunocytochemical analyses. The use of a cell culture model allows for the fixation and visualization of the actin cytoskeleton with minimal disorganization. In summary, alginate beads provide a reliable culture system for the maintenance of pituitary adenoma cells.

Three-dimensional culture in alginate beads, due to its simplicity and reproducibility, was chosen to maintain the pituitary adenoma cells. The procedures included an initial enzymatic digestion and mechanical dissociation of the tumor tissue, and the subsequent cell suspension was encapsulated in alginate beads.

ヒト下垂体腺腫細胞の三次元アルギン酸ビーズ文化

A three-dimensional culture method is described in which primary pituitary adenoma cells are grown in alginate beads. Alginate is a polymer derived from ...

Core/shell Printing Scaffolds For Tissue Engineering Of Tubular Structures

Three-dimensional (3D) printing of core/shell filaments allows direct fabrication of channel structures with a stable shell that is cross-linked at the interface with a liquid core. The latter is removed post-printing, leaving behind a hollow tube. Integrating an additive manufacturing technique (like the one described here with tailor-made [bio]inks, which structurally and biochemically mimic the native extracellular matrix [ECM]) is an important step towards advanced tissue engineering. However, precise fabrication of well-defined structures requires tailored fabrication strategies optimized for the material in use. Therefore, it is sensible to begin with a set-up that is customizable, simple-to-use, and compatible with a broad spectrum of materials and applications. This work presents an easy-to-manufacture core/shell nozzle with luer-compatibility to explore core/shell printing of woodpile structures, tested with a well-defined, alginate-based scaffold material formulation.

Presented here is a simple-to-use, core/shell, three-dimensional bioprinting set-up for one-step fabrication of hollow scaffolds, suitable for tissue engineering of vascular and other tubular structures.

管状構造の組織工学のためのコア/シェル印刷足場

Three-dimensional (3D) printing of core/shell filaments allows direct fabrication of channel structures with a stable shell that is cross-linked at the ...

Microgel-Extracellular Matrix Composite Support for the Embedded 3D Printing of Human Neural Constructs

The embedded 3D printing of cells inside a granular support medium has emerged in the past decade as a powerful approach for the freeform biofabrication of soft tissue constructs. However, granular gel formulations have been restricted to a limited number of biomaterials that allow for the cost-effective generation of large amounts of hydrogel microparticles. Therefore, granular gel support media have generally lacked the cell-adhesive and cell-instructive functions found in the native extracellular matrix (ECM).
To address this, a methodology has been developed for the generation of self-healing annealable particle-extracellular matrix (SHAPE) composites. SHAPE composites consist of a granular phase (microgels) and a continuous phase (viscous ECM solution) that, together, allow for both programmable high-fidelity printing and an adjustable biofunctional extracellular environment. This work describes how the developed methodology can be utilized for the precise biofabrication of human neural constructs.
First, alginate microparticles, which serve as the granular component in the SHAPE composites, are fabricated and combined with a collagen-based continuous component. Then, human neural stem cells are printed inside the support material, followed by the annealing of the support. The printed constructs can be maintained for weeks to allow the differentiation of the printed cells into neurons. Simultaneously, the collagen continuous phase allows for axonal outgrowth and the interconnection of regions. Finally, this works provides information on how to perform live-cell fluorescence imaging and immunocytochemistry to characterize the 3D-printed human neural constructs.

This work describes a protocol for the freeform embedded 3D printing of neural stem cells inside self-healing annealable particle-extracellular matrix composites. The protocol enables the programmable patterning of interconnected human neural tissue constructs with high fidelity.

ヒト神経構築物の埋め込み3D印刷のためのミクロゲル-細胞外マトリックス複合サポート

The embedded 3D printing of cells inside a granular support medium has emerged in the past decade as a powerful approach for the freeform biofabrication ...