This project was supported by grants NIH NIGMS 8P41 GM103540-28 and P50-GM076516

1試料の調製<ol><li> 10％ウシ胎児血清およびペニシリンストレプトマイシン50μgの/ mlの100 IU / mlを補足したDMEMを用いて組織培養フラスコ中CHOK1細胞を維持する。 37℃で5％CO 2の加湿インキュベーターで細胞を培養する。 </li><li>収穫した後、0.16ミリメートルの表面厚さで直径14mmのマイクロウェルにCHOK1細胞をプレート。イメージング、周りの60〜70％の集密度に最適な密度のための種の細胞。 </li><li> 37°C、5％CO 2で一晩細胞をインキュベートする。 HBSS（ハンクス緩衝生理食塩液）中で細胞を3回洗浄し、リソトラッカーDND26の50 nMの緑とチューブリントラッカーグリーンの150 nMのを含む溶液で細胞を培養する。 37℃で1時間、細胞をインキュベートする。オプションの手順：インキュベーションに先立って、ミトコンドリアマトリックス染色色素（25 nM）を用いて付加的な染色を行う。 </li><li>未結合の色素を除去し、HBSSで細胞を3回洗浄する。虚部の前に新鮮なDMEM増殖培地を追加します。細胞をる。 </li></ol> 2顕微鏡の構成ビデオプロトコルに記載粒子追跡用顕微鏡は、市販の倒立顕微鏡（ 図4）のフレームに組み付けられている。しかし3D軌道粒子追跡のための商用モジュールが利用可能になりました。 <ol><li> 690 nmの1040 nmの波長可変出力波長範囲は、Saはフェムト秒レーザー励起光源：コヒーレントカメレオン-ウルトラIIチタンを使用してください。 </li><li>レーザ光は、IRコーティングされたミラーを用いて顕微鏡の背面ポートに揃っていることを確認します。レーザビームは、方解石直線偏光子に続いて回転半波長板を用いて減衰される。サンプルの平均電力は、0.5〜2 mWの間にあるようにビームを減衰させる。 注：レーザ光が試料面内の集束ビームの位置および軌道の制御を可能にするガルバノモータ作動一対のミラーによって反射される。中にショートパスダイクロイックミラーでの反射後の顕微鏡対物レンズの後方に入る前に、ビームエキスパンダを通過するガルバノミラーから出るコリメートされたレーザビームが拡大される典型的な構成（10X）。 </li><li>光路内に高開口数水目標（60X、NA 1.2）を配置することにより、試料からの蛍光発光を収集します。 1つまたは2つのチャネル構成で所望の発光波長に応じて蛍光フィルタキューブを選択する。さらに、放出された蛍光のスペクトル範囲を選択するために、発光帯域フィルタを採用している。 </li><li>電動ステージ上にサンプルを置き、客観的なピエゾコントローラを使用して顕微鏡対物レンズの微動を調整します。 </li><li>信号を判別し、デジタルI / Oデータ取得カードに送信される光電子増倍管にフィルターキューブからの光を導く。 注：コンピュータの波形は、I / Oカードのアナログ出力であり、提供します：ある生成されたスキャナ制御エレクトロニクス編。光電子増倍管やスキャナへの出力信号から光子計数入力を測定し、蛍光ダイナミクスSimFCSソフトウェアのための研究所のI / Oカードを介して制御される。 </li></ol> 3イメージング<ol><li>ステージ上のセルを置き、透過光照明を使用して焦点を合わせる。 </li><li>色素を取り込んだ細胞を同定する基礎となる微小管を可視化するために、ラスタースキャン画像に切り替える。小胞の動きが存在している初期領域を特定します。 </li><li>孤立した小胞が識別されると、軌道追跡のための次のパラメータを設定します。 <ol><li>追跡されている粒子の大きさに合わせて円形走査のサイズを定義する軌道の半径を選択します。ポイントエミッタでは、感度および応答を最大にする励起光の点広がり関数（PSF）の腰部に等しい軌道の半径を設定する。 </li><li>軸方向を設定します。軸方向に沿った粒子位置を局在化するために行わ二つの軌道との間の距離を定義する距離。 1.5-3倍のPSF腰までの軸方向の距離を設定します。 </li><li>また、光漂白速度を決定する軌道の各点に費やされた時間を設定するために、粒子の明るさに応じて滞留時間を定義する。 10〜100秒の間の滞留時間を使用してください。 </li><li> 4-32ミリ秒のオーダーで軌道周期が得られ、粒子の位置を決定するための高い時間分解能を提供するために、64または128にそれぞれ軌道の点の数を設定します。 </li></ol></li><li>ラスタースキャンされた画像のカーソル選択により、グラフィカル·ユーザー·インターフェースを介して粒子上にビームをセンタリングするために、ミラーに送信された信号を、DCオフセットを変更します。 </li><li>軌道スキャンラスタイメージングから顕微鏡モードを切り替えることで、追跡を開始します。 </li><li>フィードバックとデータ収集を有効にします。 </li></ol> 4。TrajectORY分析<ol><li>軌道に沿って「強度カーペット」の形式で、各時点での各ポイントで収集された蛍光を表示するには、ソフトウェアを使用してください。カーペットに沿って収集された強度は、他の明るい物体と粒子の相互作用に関する情報を提供します。同様に、時系列の形で時間の経過とともに光電子増倍管から採取し、蛍光強度の（x、yスキャナおよびz -piezoの時間にわたってDC変位すなわち ）軌跡情報の両方を表示するためにソフトウェアを使用する。 </li><li>軌道内の関心領域のみを選択するために、時系列表現と「強度カーペット」の情報を使用してください。 </li><li>粒子軌道の選択された部分の2次元投影を表示するには、ソフトウェアを使用してください。粒子の蛍光強度に応じて色分けする軌道を適切なコントロールを選択します。 </li><li>ページを表示するオプションを選択します蛍光強度に応じて3Dで記事軌道、および色分けそれ。微小管に沿ってリソソームの動きの特徴を視覚化するためにコントロールを使用して3Dで軌道を回転させます。 </li></ol>

<ol>
	<li>So, P. T., Dong, C. Y., Masters, B. R., Berland, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two+photon+excitation+fluorescence+microscopy.">Two photon excitation fluorescence microscopy.</a> Annu Rev Biomed Eng. 2, 399-429 (2000).</li><li>Dupont, A., Lamb, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoscale+three+dimensional+single+particle+tracking.">Nanoscale three dimensional single particle tracking.</a> Nanoscale. 3, 4532-4541 (2011).</li><li>Estrada, L. 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S., Lakadamyali, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlative+live+cell+and+superresolution+microscopy+reveals+cargo+transport+dynamics+at+microtubule+intersections.">Correlative live cell and superresolution microscopy reveals cargo transport dynamics at microtubule intersections.</a> Proceedings of the National Academy of Sciences of the United States of America. 110, 3375-3380 (2013).</li><li>Huotari, J., Helenius, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endosome+maturation.">Endosome maturation.</a> Embo Journal. 30, 3481-3500 (2011).</li><li>Ragan, T., So, P. T., Kwon, H. 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The authors have nothing to disclose.

ここ数年、蛍光顕微鏡技術とインストルメンテーションの驚異的な進歩にもかかわらず、高い時間分解能で三次元での蛍光粒子の軌跡を達成することは、フィールドでの課題となってきた。高い時間分解能は、二次元でトラッキング粒子が達成された場合には、軸方向への拡張は、典型的には、システム10の周波数応答の劇的な減少をもたらす。 このビデオプロ?...

アプローチは、多数の顕微鏡を用いて三次元で蛍光粒子を追跡するためにこれまでに開発されてきた。ほとんどのアプローチは、理想的には、典型的には、軸方向にトラッキングを達成するために、顕微鏡の発光光学系のカスタマイズされた修飾と組み合わせた二次元的に追跡するために適した、高速カメラの使用に依存する。このプロセスは、典型的には、時間がかかり、かつ粒子が追跡されている場合にのみ、妥当な時間分解能（10 Hz）をされ得たが、レーザ走査型顕微鏡（共焦点またはつの光子のいずれか）は従来のz-スタックの時間シーケンスを実行することにより、蛍光粒子を追跡することができ能動的フィードバック機構2により小さなラスタ撮像領域の中心に保った。 ロックイン粒子にするという考えは、軌道追跡法の拠点となっています。代わりに、ラスタの円軌道を蛍光粒子の周囲に実行されるスキャンします。に沿って蛍光の強度軌道は正確に粒子位置4を局在する。 粒子の局所的な位置は、顕微鏡スキャナおよび再中央粒子位置の軌道を作動させるために使用することができる。顕微鏡のガルバノスキャナはアナログ電圧によって駆動される。この電圧の交流成分、 すなわち正弦波、集束レーザビームを軌道を行うことができ、XとYスキャンミラーに適用される余弦波を円軌道を実行可能にする。信号のDCオフセットは、軌道中心の位置を変化させることを容易にする。軌道周期が決定され、AC信号の波形が設定されると、フィードバックシステムは、信号のDC成分のみを更新する必要がある。 検出器から収集した蛍光シグナルを読み取ることができるソフトウェアは、スキャナおよび検出器を制御するために、粒子の位置を計算し、DC電源をオフに更新が要求されるセット。軌道パラメータ（サイズ及びタイミング）の注意深い選択を撮像成功したフィードバックに必要なこれらのパラメータは、追跡する必要がある蛍光粒子の特性に基づいて調整されなければならないれる。 技術の物理的および数学的な基礎は、2Dと3D両方のアプリケーションのために、過去4,5で説明した。このプロトコルでは、簡単にセットアップの主要なハードウェアコンポーネントを記述し、より詳細にパラメータの選択と私たちは、生細胞内で高い時間分解能でのリソソームの変位を可能にする以下の典型的な実験に必要なサンプル調製。

<table border="0" cellpadding="0" cellspacing="0" width="525">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:197px;">Name</td>
			<td style="width:160px;">Company</td>
			<td style="width:168px;">Model</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Lysotracker DND 26</td>
			<td>Life technologies</td>
			<td>L-7526</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">tubuline tracker Green</td>
			<td>Life technologies</td>
			<td>T34075</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Mitotracker RED</td>
			<td>Life technologies</td>
			<td>M7512</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Coherent Chamelon- ultra II TI</td>
			<td>Coherent</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Calcite polarize</td>
			<td>Melles Griot Glan&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Galvanometer-motor mirror</td>
			<td>Cambridge technologies</td>
			<td>M 6350</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Dichroic mirror</td>
			<td>Chroma technologies</td>
			<td>700 DCSPXR</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Motorized stage</td>
			<td>ASI</td>
			<td>MS2000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Piezo&#160;</td>
			<td>PI</td>
			<td>P721-LLQ</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Photomultiplier tube</td>
			<td>Hamamatsu</td>
			<td>H7422P-40</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Data acquisition card</td>
			<td>IO tech</td>
			<td>PCI 1128-4000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Imaging software</td>
			<td>LFD</td>
			<td>Global for images-SimFCS</td>
		</tr>
	</tbody>
</table>

3d orbital tracking in a modified two-photon microscope: an application to the tracking of intracellular vesicles

このビデオプロトコルの目的は、改変された二光子顕微鏡1を用いた三次元蛍光軌道粒子追跡実験を行い、分析する方法を議論することである。従来のアプローチ（ラスタスキャンまたは広視野フレームのスタックに基づく）とは対照的に、3D軌道追跡は、3次元変位を局所化し、高い空間（10nmの精度）と時間分解能（50 Hzの周波数応答）で追従させるミクロン2、数百の長さスケールに移る蛍光粒子。方法は、追跡される物体の周りの円軌道を実行するために二光子レーザー走査顕微鏡のハードウェアを制御フィードバックアルゴリズムに基づいている：フィードバック機構は、変位を制御することにより、中央に蛍光被写体を維持する走査ビーム3-5。この技術の利点を実証するために、私たちはアル中で動きの速い細胞小器官、リソソームを、続いてivingセル6,7。細胞は、標準的なプロトコルに従って播種し、商業的にリソソーム色素を用いて染色した。私たちは、生きた細胞内の3D軌道追跡実験を行うために、短時間のハードウェア構成をより詳細に制御ソフトウェアを議論する。私たちは、詳細に走査顕微鏡を制御し、粒子の周りに周回軌道でビームの運動を可能にするために必要なパラメータを議論する。私たちは、この方法が効果的に生きた細胞内の3Dでの微小管に沿っラベルリソソームの速い動きを追跡するために使用することができる方法を示すことで結論付けている。リソソームは、典型的には、微小管ネットワーク8に沿って向けられた動きを表示し、0.4ミクロン/秒の範囲の速度で移動することができる。

このプロトコルによれば、高速3D単一粒子追跡は、蛍光標識されたリソソームの変位を追跡するために修飾された二光子顕微鏡を用いて生細胞の内部で行うことができる。行った実験は、エンドソーム成熟過程9後の細胞内を移動する孤立したリソソームの追跡で構成されています。リソソームは、蛍光緑の色素を用いて染色し、2光子励起を利用し930 nmで励起した。本発明者らのデー?...

Watch this Scientific Journal Video about 3D Orbital Tracking in a Modified Two-photon Microscope: An Application to the Tracking of Intracellular Vesicles at JoVE.com

3D Orbital Tracking in a Modified Two-photon Microscope: An Application to the Tracking of Intracellular Vesicles

In this video protocol we track - at high speed and in three dimensions - fluorescently labeled lysosomes within living cells, using the orbital tracking method in a modified two-photon microscope.

細胞内小胞の追跡への応用：変形二光子顕微鏡での3d軌道の追跡

The objective of this video protocol is to discuss how to perform and analyze a three-dimensional fluorescent orbital particle tracking experiment using a ...

3d-orbital-tracking-modified-two-photon-microscope-an-application-to

Research

JoVE Journal

Bioengineering

10.1K ビュー.  University of California, Irvine. In this video protocol we track - at high speed and in three dimensions - fluorescently labeled lysosomes within living cells, using the orbital tracking method in a modified two-photon microscope. 

ビデオ: 3D Orbital Tracking in a Modified Two-photon Microscope: An Application to the Tracking of Intracellular Vesicles

Tracking Hypoxic Signaling within Encapsulated Cell Aggregates

In Diabetes mellitus type 1, autoimmune destruction of the pancreatic &beta;-cells results in loss of insulin production and potentially lethal hyperglycemia. As an alternative treatment option to exogenous insulin injection, transplantation of functional pancreatic tissue has been explored1,2. This approach offers the promise of a more natural, long-term restoration of normoglycemia. Protection of the donor tissue from the host's immune system is required to prevent rejection and encapsulation is a method used to help achieve this aim.
Biologically-derived materials, such as alginate3 and agarose4, have been the traditional choice for capsule construction but may induce inflammation or fibrotic overgrowth5 which can impede nutrient and oxygen transport. Alternatively, synthetic poly(ethylene glycol) (PEG)-based hydrogels are non-degrading, easily functionalized, available at high purity, have controllable pore size, and are extremely biocompatible,6,7,8. As an additional benefit, PEG hydrogels may be formed rapidly in a simple photo-crosslinking reaction that does not require application of non-physiological temperatures6,7. Such a procedure is described here. In the crosslinking reaction, UV degradation of the photoinitiator, 1-[4-(2-Hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (Irgacure 2959), produces free radicals which attack the vinyl carbon-carbon double bonds of dimethacrylated PEG (PEGDM) inducing crosslinking at the chain ends. Crosslinking can be achieved within 10 minutes. PEG hydrogels constructed in such a manner have been shown to favorably support cells7,9, and the low photoinitiator concentration and brief exposure to UV irradiation is not detrimental to viability and function of the encapsulated tissue10. While we methacrylate our PEG with the method described below, PEGDM can also be directly purchased from vendors such as Sigma.
An inherent consequence of encapsulation is isolation of the cells from a vascular network. Supply of nutrients, notably oxygen, is therefore reduced and limited by diffusion. This reduced oxygen availability may especially impact &beta;-cells whose insulin secretory function is highly dependent on oxygen11-13. Capsule composition and geometry will also impact diffusion rates and lengths for oxygen. Therefore, we also describe a technique for identifying hypoxic cells within our PEG capsules. Infection of the cells with a recombinant adenovirus allows for a fluorescent signal to be produced when intracellular hypoxia-inducible factor (HIF) pathways are activated14. As HIFs are the primary regulators of the transcriptional response to hypoxia, they represent an ideal target marker for detection of hypoxic signaling15. This approach allows for easy and rapid detection of hypoxic cells. Briefly, the adenovirus has the sequence for a red fluorescent protein (Ds Red DR from Clontech) under the control of a hypoxia-responsive element (HRE) trimer. Stabilization of HIF-1 by low oxygen conditions will drive transcription of the fluorescent protein (Figure 1). Additional details on the construction of this virus have been published previously15. The virus is stored in 10% glycerol at -80&deg; C as many 150 &mu;L aliquots in 1.5 mL centrifuge tubes at a concentration of 3.4 x 1010 pfu/mL. 
Previous studies in our lab have shown that MIN6 cells encapsulated as aggregates maintain their viability throughout 4 weeks of culture in 20% oxygen. MIN6 aggregates cultured at 2 or 1% oxygen showed both signs of necrotic cells (still about 85-90% viable) by staining with ethidium bromide as well as morphological changes relative to cells in 20% oxygen. The smooth spherical shape of the aggregates displayed at 20% was lost and aggregates appeared more like disorganized groups of cells. While the low oxygen stress does not cause a pronounced drop in viability, it is clearly impacting MIN6 aggregation and function as measured by glucose-stimulated insulin secretion15. Western blot analysis of encapsulated cells in 20% and 1% oxygen also showed a significant increase in HIF-1&alpha; for cells cultured in the low oxygen conditions which correlates with the expression of the DsRed DR protein.

A method for photo-encapsulation of cells in a crosslinked PEG hydrogel is described. Hypoxic signaling within encapsulated murine insulinoma (MIN6) aggregates is tracked using a fluorescent marker system. This system allows serial examination of cells within a hydrogel scaffold and correlation of hypoxic signaling with changes in cell phenotype.

カプセル化された細胞凝集体の中で低酸素シグナルの追跡

In Diabetes mellitus type 1, autoimmune destruction of the pancreatic &beta;-cells results in loss of insulin production and potentially lethal ...

生物工学

Longitudinal Measurement of Extracellular Matrix Rigidity in 3D Tumor Models Using Particle-tracking Microrheology

The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and modified as part of a set of complex, two-way mechanosensitive interactions. While the development of biologically-relevant 3D tumor models have facilitated mechanistic studies on the impact of matrix rheology on tumor growth, the inverse problem of mapping changes in the mechanical environment induced by tumors remains challenging. Here, we describe the implementation of particle-tracking microrheology (PTM) in conjunction with 3D models of pancreatic cancer as part of a robust and viable approach for longitudinally monitoring physical changes in the tumor microenvironment, in situ. The methodology described here integrates a system of preparing in vitro 3D models embedded in a model extracellular matrix (ECM) scaffold of Type I collagen with fluorescently labeled probes uniformly distributed for position- and time-dependent microrheology measurements throughout the specimen. In vitro tumors are plated and probed in parallel conditions using multiwell imaging plates. Drawing on established methods, videos of tracer probe movements are transformed via the Generalized Stokes Einstein Relation (GSER) to report the complex frequency-dependent viscoelastic shear modulus, G*(&#969;). Because this approach is imaging-based, mechanical characterization is also mapped onto large transmitted-light spatial fields to simultaneously report qualitative changes in 3D tumor size and phenotype. Representative results showing contrasting mechanical response in sub-regions associated with localized invasion-induced matrix degradation as well as system calibration, validation data are presented. Undesirable outcomes from common experimental errors and troubleshooting of these issues are also presented. The 96-well 3D culture plating format implemented in this protocol is conducive to correlation of microrheology measurements with therapeutic screening assays or molecular imaging to gain new insights into impact of treatments or biochemical stimuli on the mechanical microenvironment.

Particle-tracking microrheology can be used to non-destructively quantify and spatially map changes in extracellular matrix mechanical properties in 3D tumor models.

粒子追跡マイクロレオロジーを用いて3次元腫瘍モデルにおける細胞外マトリックス剛性の縦測定

The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and ...

Long-term Intravital Immunofluorescence Imaging of Tissue Matrix Components with Epifluorescence and Two-photon Microscopy

Besides being a physical scaffold to maintain tissue morphology, the extracellular matrix (ECM) is actively involved in regulating cell and tissue function during development and organ homeostasis. It does so by acting via biochemical, biomechanical, and biophysical signaling pathways, such as through the release of bioactive ECM protein fragments, regulating tissue tension, and providing pathways for cell migration. The extracellular matrix of the tumor microenvironment undergoes substantial remodeling, characterized by the degradation, deposition and organization of fibrillar and non-fibrillar matrix proteins. Stromal stiffening of the tumor microenvironment can promote tumor growth and invasion, and cause remodeling of blood and lymphatic vessels. Live imaging of matrix proteins, however, to this point is limited to fibrillar collagens that can be detected by second harmonic generation using multi-photon microscopy, leaving the majority of matrix components largely invisible. Here we describe procedures for tumor inoculation in the thin dorsal ear skin, immunolabeling of extracellular matrix proteins and intravital imaging of the exposed tissue in live mice using epifluorescence and two-photon microscopy. Our intravital imaging method allows for the direct detection of both fibrillar and non-fibrillar matrix proteins in the context of a growing dermal tumor. We show examples of vessel remodeling caused by local matrix contraction. We also found that fibrillar matrix of the tumor detected with the second harmonic generation is spatially distinct from newly deposited matrix components such as tenascin C. We also showed long-term (12 hours) imaging of T-cell interaction with tumor cells and tumor cells migration along the collagen IV of basement membrane. Taken together, this method uniquely allows for the simultaneous detection of tumor cells, their physical microenvironment and the endogenous tissue immune response over time, which may provide important insights into the mechanisms underlying tumor progression and ultimate success or resistance to therapy.

The extracellular matrix undergoes substantial remodeling during wound healing, inflammation and tumorigenesis. We present a novel intravital immunofluorescence microscopy approach to visualize the dynamics of fibrillar as well as mesh-like matrix components with high spatial and temporal resolution using epifluorescence or two-photon microscopy.

落射蛍光による組織マトリックスのコンポーネントと二光子顕微鏡の長期生体内免疫蛍光イメージング

Besides being a physical scaffold to maintain tissue morphology, the extracellular matrix (ECM) is actively involved in regulating cell and tissue ...

In Situ Mapping of the Mechanical Properties of Biofilms by Particle-tracking Microrheology

Bacterial cells are able to form surface-attached biofilm communities known as biofilms by encasing themselves in extracellular polymeric substances (EPS). The EPS serves as a physical and protective scaffold that houses the bacterial cells and consists of a variety of materials that includes proteins, exopolysaccharides and DNA. The composition of the EPS may change, which remodels the mechanic properties of the biofilm to further develop or support alternative biofilm structures, such as streamers, as a response to environmental cues. Despite this, there are little quantitative descriptions on how EPS components contribute to the mechanical properties and function of biofilms. Rheology, the study of the flow of matter, is of particular relevance to biofilms as many biofilms grow in flow conditions and are constantly exposed to shear stress. It also provides measurement and insight on the spreading of the biofilm on a surface. Here, particle-tracking microrheology is used to examine the viscoelasticity and effective crosslinking roles of different matrix components in various parts of the biofilm during development. This approach allows researchers to measure mechanic properties of biofilms at the micro-scale, which might provide useful information for controlling and engineering biofilms.

In Situ Mapping of the Mechanical Properties of Biofilms by Particle-tracking Microrheology

Particle-tracking microrheology investigates the viscoelasticity of materials. Here, the technique is used to determine the viscoelasticity, creep compliance and effective crosslinking roles of different matrix components of a bacterial biofilm. The matrix consists of polymeric substances secreted by the bacteria and its components determine biofilm structure and mechanical properties.

粒子追跡マイクロレオロジーによりバイオフィルムの機械的特性のその場でのマッピング

Bacterial cells are able to form surface-attached biofilm communities known as biofilms by encasing themselves in extracellular polymeric substances ...

Microfluidic Platform with Multiplexed Electronic Detection for Spatial Tracking of Particles

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to spatially fractionate the sample based on a biological property of interest. For the resultant spatial distribution to be used as the assay readout, microfluidic devices are often subjected to microscopic analysis requiring complex instrumentation with higher cost and reduced portability. To address this limitation, we have developed an integrated electronic sensing technology for multiplexed detection of particles at different locations on a microfluidic chip. Our technology, called Microfluidic CODES, combines Resistive Pulse Sensing with Code Division Multiple Access to compress 2D spatial information into a 1D electrical signal. In this paper, we present a practical demonstration of the Microfluidic CODES technology to detect and size cultured cancer cells distributed over multiple microfluidic channels. As validated by the high-speed microscopy, our technology can accurately analyze dense cell populations all electronically without the need for an external instrument. As such, the Microfluidic CODES can potentially enable low-cost integrated lab-on-a-chip devices that are well suited for the point-of-care testing of biological samples.

We demonstrate a microfluidic platform with an integrated surface electrode network that combines resistive pulse sensing (RPS) with code division multiple access (CDMA), to multiplex detection and sizing of particles in multiple microfluidic channels.

粒子の空間追跡のための多重化された電子の検出とマイクロ流体プラットフォーム

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to ...

Assembly and Tracking of Microbial Community Development within a Microwell Array Platform

The development of microbial communities depends on a combination of complex deterministic and stochastic factors that can dramatically alter the spatial distribution and activities of community members. We have developed a microwell array platform that can be used to rapidly assemble and track thousands of bacterial communities in parallel. This protocol highlights the utility of the platform and describes its use for optically monitoring the development of simple, two-member communities within an ensemble of arrays within the platform. This demonstration uses two mutants of Pseudomonas aeruginosa, part of a series of mutants developed to study Type VI secretion pathogenicity. Chromosomal inserts of either mCherry or GFP genes facilitate the constitutive expression of fluorescent proteins with distinct emission wavelengths that can be used to monitor community member abundance and location within each microwell. This protocol describes a detailed method for assembling mixtures of bacteria into the wells of the array and using time-lapse fluorescence imaging and quantitative image analysis to measure the relative growth of each member population over time. The seeding and assembly of the microwell platform, the imaging procedures necessary for the quantitative analysis of microbial communities within the array, and the methods that can be used to reveal interactions between microbial species area all discussed.

The development of microbial communities depends on a combination of factors, including environmental architecture, member abundance, traits, and interactions. This protocol describes a synthetic, microfabricated environment for the simultaneous tracking of thousands of communities contained in femtoliter wells, where key factors such as niche size and confinement can be approximated.

マイクロウェルアレイプラットフォーム内での微生物コミュニティ開発の組み立てと追跡

The development of microbial communities depends on a combination of complex deterministic and stochastic factors that can dramatically alter the spatial ...

A Protocol for Real-time 3D Single Particle Tracking

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although various RT-3D-SPT methods have been put forward in recent years, tracking high speed 3D diffusing particles at low photon count rates remains a challenge. Moreover, RT-3D-SPT setups are generally complex and difficult to implement, limiting their widespread application to biological problems. This protocol presents a RT-3D-SPT system named 3D Dynamic Photon Localization Tracking (3D-DyPLoT), which can track particles with high diffusive speed (up to 20 &#181;m2/s) at low photon count rates (down to 10 kHz). 3D-DyPLoT employs a 2D electro-optic deflector (2D-EOD) and a tunable acoustic gradient (TAG) lens to drive a single focused laser spot dynamically in 3D. Combined with an optimized position estimation algorithm, 3D-DyPLoT can lock onto single particles with high tracking speed and high localization precision. Owing to the single excitation and single detection path layout, 3D-DyPLoT is robust and easy to set up. This protocol discusses how to build 3D-DyPLoT step by step. First, the optical layout is described. Next, the system is calibrated and optimized by raster scanning a 190 nm fluorescent bead with the piezoelectric nanopositioner. Finally, to demonstrate real-time 3D tracking ability, 110 nm fluorescent beads are tracked in water.

This protocol details the construction and operation of a real-time 3D single particle tracking microscope capable of tracking nanoscale fluorescent probes at high diffusive speeds and low photon count rates.

リアルタイム 3 D 単一粒子追跡のためのプロトコル

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although ...

An Orbital Shaking Culture of Mammalian Cells in O-shaped Vessels to Produce Uniform Aggregates

Suspension cultures of mammalian cell aggregates are required for various applications in medical and biotechnological fields. The disposable bag-based method is one of the simplest techniques for the mass production of cellular aggregates, but it does not protect the cultures against over-aggregation, which occurs when they gather at the bottom center of the culture vessel. To solve this problem, we developed an O-shaped dish and an O-shaped bag, neither of which contains a central region. Aggregates grown in either O-shaped culture vessel were noticeably more uniform in size than aggregates grown in conventional vessels. Histological analyses showed that aggregates in conventional culture dishes contained necrotic cores most likely caused by a poor oxygen supply. In contrast, aggregates that were grown in the O-shaped bag, even those with similar diameters to aggregates in conventional culture dishes, did not show necrotic cores. These results suggest that the O-shaped bag provides sufficient oxygen to the aggregates due to the oxygen permeability of the bag material. We, therefore, propose that this novel gas-permeable O-shaped culture bag is suitable for the mass production of uniform aggregates that are necessary in various biotechnological fields.

Here we present a protocol for using O-shaped vessels, specialized for suspension cultures of cellular aggregates, with orbital shaking. The HEK293 cells grown in this bag form more homogeneous aggregates than those grown in conventional culture vessels.

哺乳類細胞培養を均一な骨材を生産する O の形をした船で揺れ、軌道

Suspension cultures of mammalian cell aggregates are required for various applications in medical and biotechnological fields. The disposable bag-based ...

Segmenting Growth of Endothelial Cells in 6-Well Plates on an Orbital Shaker for Mechanobiological Studies

Shear stress imposed on the arterial wall by the flow of blood affects endothelial cell morphology and function. Low magnitude, oscillatory and multidirectional shear stresses have all been postulated to stimulate a pro-atherosclerotic phenotype in endothelial cells, whereas high magnitude and unidirectional or uniaxial shear are thought to promote endothelial homeostasis. These hypotheses require further investigation, but traditional in vitro techniques have limitations, and are particularly poor at imposing multidirectional shear stresses on cells. 
One method that is gaining increasing use is to culture endothelial cells in standard multi-well plates on the platform of an orbital shaker; in this simple, low-cost, high-throughput and chronic method, the swirling medium produces different patterns and magnitudes of shear, including multidirectional shear, in different parts of the well. However, it has a significant limitation: cells in one region, exposed to one type of flow, may release mediators into the medium that affect cells in other parts of the well, exposed to different flows, hence distorting the apparent relation between flow and phenotype. 
Here we present an easy and affordable modification of the method that allows cells to be exposed only to specific shear stress characteristics. Cell seeding is restricted to a defined region of the well by coating the region of interest with fibronectin, followed by passivation using passivating solution. Subsequently, the plates can be swirled on the shaker, resulting in exposure of cells to well-defined shear profiles such as low magnitude multidirectional shear or high magnitude uniaxial shear, depending on their location. As before, the use of standard cell-culture plasticware allows straightforward further analysis of the cells. The modification has already allowed the demonstration of soluble mediators, released from endothelium under defined shear stress characteristics, that affect cells located elsewhere in the well.

This protocol describes a coating method to restrict endothelial cell growth to a specific region of a 6-well plate for shear stress application using the orbital shaker model.

メカノ生物学的研究のための軌道シェーカー上の6ウェルプレートにおける内皮細胞の成長のセグメント化

Shear stress imposed on the arterial wall by the flow of blood affects endothelial cell morphology and function. Low magnitude, oscillatory and ...

An In vitro System to Gauge the Thrombolytic Efficacy of Histotripsy and a Lytic Drug

Deep vein thrombosis (DVT) is a global health concern. The primary approach to achieve vessel recanalization for critical obstructions is catheter-directed thrombolytics (CDT). To mitigate caustic side effects and the long treatment time associated with CDT, adjuvant and alternative approaches are under development. One such approach is histotripsy, a focused ultrasound therapy to ablate tissue via bubble cloud nucleation. Pre-clinical studies have demonstrated strong synergy between histotripsy and thrombolytics for clot degradation. This report outlines a benchtop method to assess the efficacy of histotripsy-aided thrombolytic therapy, or lysotripsy.
Clots manufactured from fresh human venous blood were introduced into a flow channel whose dimensions and acousto-mechanical properties mimic an iliofemoral vein. The channel was perfused with plasma and the lytic&#160;recombinant tissue-type plasminogen activator. Bubble clouds were generated in the clot with a focused ultrasound source designed for the treatment of femoral venous clots. Motorized positioners were used to translate the source focus along the clot length. At each insonation location, acoustic emissions from the bubble cloud were passively recorded, and beamformed to generate passive cavitation images. Metrics to gauge treatment efficacy included clot mass loss (overall treatment efficacy), and the concentrations of D-dimer (fibrinolysis) and hemoglobin (hemolysis) in the perfusate. There are limitations to this in vitro design, including lack of means to assess in vivo side effects or dynamic changes in flow rate as the clot lyses. Overall, the setup provides an effective method to assess the efficacy of histotripsy-based strategies to treat DVT.

Histotripsy-aided lytic delivery or lysotripsy is under development for the treatment of deep vein thrombosis. An in vitro procedure is presented here to assess the efficacy of this combination therapy. Key protocols for the clot model, image guidance, and assessment of treatment efficacy are discussed.