Name: observing and quantifying fibroblast-mediated fibrin gel compaction
Uploaded: 2014-01-16T13:45:00
Description: Watch this Scientific Journal Video about Observing and Quantifying Fibroblast-mediated Fibrin Gel Compaction at JoVE.com

ジョージ・ジュディスとスティーブン・エリアソンは、ヒトの真皮線維芽細胞とラメシュ・ラグパシーに株追跡アルゴリズムの助けを寄付してくれたことに感謝します。この作業の支援は、米国教育省の国家支援フェローシップ(GAANN P200A120071)の大学院支援によって提供されました。

1. ステンシルの準備
パラフィルム上にステンシルを用意して、各外植の位置を、目的のジオメトリ(図1A および 1B)に従ってレイアウトします。スペースは、約1〜2ミリメートル離れて各植え出し。この距離は、外植間の繊維の整列を生成するための理想的な間隔に対応します。カバーグラスの下に、サンプルをテープで用意する場所の...

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このプロトコルは、細胞介在ECMリモデリングに関与する力学を観察し、定量化することを目的として開発されました。このようなプロセスは、多くの生物現象の根源であり、工学組織2,22に重要な意味を持ち、瘢痕1,23を減少させ、病理学的組織改修を理解する12,24。タイムラプスDIC顕微鏡を使用することで、細胞牽引力の結果として生じるフィブリン繊維の変位と位置...

細胞とマトリックスの相互作用を研究するための重要なツールは、細胞に取り込まれたコラーゲンゲル1,2である。ゲルは、組織の in vivo 特性に近く、従来の2D培養3によって提供されるよりも細胞の挙動を理解するのに適した3D環境を提供する。線維芽細胞がコラーゲンゲル内に均一に分布していた初期の研究では、細胞がコラーゲン線維を急速に統合し、ゲル4,5をコンパクト化することを発見した。フリーフローティングゲルの収縮線維芽細胞は、ゲルが完全に圧縮1,6,7に達した直後に静止状態に移行する。境界で拘束されたゲル中の線維芽細胞は活性な合成状態8のままであり、ゲル幾何学と外部拘束に依存する方法で繊維アライメントを生成する5,9。細胞活性の違いは、細胞がゲル内のコラーゲン線維にインテグリンを介して牽引力を発揮するにつれて発症する内部張力(またはその欠如)の結果であるように思われる。
この技術の変形は、線維芽細胞の外植体(すなわち細胞の塊)をコラーゲンゲル内に離れた距離に配置し、細胞とマトリックスの相互作用を観察し、外植体(靭帯状ストラップと呼ばれることもある)10-12の間の繊維アライメントの段階的な発達を含む。外植システムの主な利点は、細胞を単純な幾何学的パターンに配置できるため、細胞駆動型繊維再調整の基礎となるメカニズムをより簡単に視覚化して調査できることです。これらのアライメントパターンは、主に細胞牽引力、細胞空間分布、ゲル形状、およびゲル上の機械的制約間の相互作用に依存するものであり、グローバル組織組織、機械的機能、および局所的な機械環境における中心的な役割を果たすため、理解することが重要である。
組織工学の分野では、機械的に機能的で工学的組織を製造するための1つの戦略は、人工組織がネイティブ組織14,15のそれを模した繊維アライメントを有するように、細胞圧縮から発生する繊維アライメントパターンを制御することを含む。このようなアライメントは、人工組織がネイティブ組織の複雑な機械的挙動を複製するために必要と考えられる。この戦略の修正は、コラーゲンゲルをフィブリンゲル16に置換することです。フィブリンゲルは、圧縮時にコラーゲンゲルと同様のアライメントパターンを発現する。時間が経つにつれて、フィブリンは分解され、初期のフィブリン繊維アライメントパターンに従う細胞合成ECMに置き換えられます。得られた工学的構造は、コラーゲンゲル由来の構築物17と比較して有意に改善された機械的特性を有する。
フィブリンゲルにおけるアライメントプロセスとその後のリモデリングイベントは、複雑で理解が不十分な方法で進行します。これらの相互作用と細胞挙動とECMリモデリングへの影響をより良く特徴付けるために、我々は、外植法に基づく手順を開発した。この方法では、線維芽細胞の外植は、異なる幾何学的パターンでフィブリンゲル上に配置される。ゲルは、環境制御された顕微鏡実装型バイオリアクター18に維持され、圧縮および繊維再調整のプロセスは、タイムラプス差動干渉コントラスト(DIC)顕微鏡で監視される。変位フィールドはカスタムアルゴリズムで定量化されます。これらの実験から得られたデータは、組織工学戦略の最適化、創傷治癒の改善、病理学的組織リモデリングの治療など、多くのプロセスに大きな影響を及ぼします。

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Sigma-Aldrich</td>
			<td>F8630</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sigma-Aldrich</td>
			<td>T4648</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gibco</td>
			<td>11965-092</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gibco</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sigma-Aldrich</td>
			<td>A2942</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sigma-Aldrich</td>
			<td>H0887</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sigma-Aldrich</td>
			<td>223506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gibco</td>
			<td>25200-056</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Invitrogen</td>
			<td>3000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lonza</td>
			<td>DE14-701F</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Molecular Probes</td>
			<td>F8858</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GIBCO</td>
			<td>A10483-01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GIBCO</td>
			<td>11430-030</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fisher-Scientific</td>
			<td>SS264-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sigma-Aldrich</td>
			<td>A3428-25MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:297px;">Biotense Bioreactor</td>
			<td style="width:85px;">ADMET</td>
			<td style="width:125px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ti-Eclipe Microscope</td>
			<td>Nikon</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"># 0 35 mm Glass Bottom Petri Dish</td>
			<td>MatTek</td>
			<td>P35G-0-20-C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"># 0 35 mm Glass Top Petri Dish</td>
			<td>MatTek</td>
			<td>P35GTOP-0-20-C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plastic Luer fittings, PVC tubing with Luer ends</td>
			<td>Cole-Parmer</td>
			<td>30600-65</td>
		</tr>
	</tbody>
</table>

observing and quantifying fibroblast-mediated fibrin gel compaction

コラーゲンおよびフィブリンゲルに埋め込まれた細胞は、ゲルの繊維に牽引力を加え、作用します。これらの力は、ゲル微細構造の局所およびグローバルな再編成および再編成につながる可能性があります。このプロセスは、細胞の位置、ゲルの幾何学的形状、およびゲルの機械的拘束との相互作用に部分的に依存する複雑な方法で進みます。これらの変数がグローバルな繊維アライメントパターンを生成する方法をよりよく理解するために、我々は、環境制御されたバイオリアクターと組み合わせたタイムラプス差動干渉コントラスト(DIC)顕微鏡を使用して、幾何学的に間隔をあけた外植(線維芽細胞のクラスター)間の圧縮プロセスを観察する。次に、画像をカスタム画像処理アルゴリズムで分析し、歪みのマップを取得します。この技術から得られた情報は、創傷治癒、疾患の発生、および組織工学の応用におけるプロセスを理解する上で重要な意味を持つ様々な細胞マトリックス相互作用のメカノバイオロジーを調査するために使用することができる。

組織のリモデリングは、細胞と周囲のマトリックスとの間の相互的な物理的相互作用によって部分的に駆動される複雑なプロセスです。細胞は周囲の繊維を再編成し、繊維ネットワークで張力を発生させる。繊維と機械環境の位置合わせは、細胞の挙動を制御し、細胞とマトリックスの両方がグローバルに再編成して再構成された組織を作り出す。本実験では、外植体の細胞は、最初は形態?...

Watch this Scientific Journal Video about Observing and Quantifying Fibroblast-mediated Fibrin Gel Compaction at JoVE.com

Observing and Quantifying Fibroblast-mediated Fibrin Gel Compaction

時間経過顕微鏡と画像処理技術は、48時間の期間にわたって環境制御バイオリアクターにおける線維芽細胞媒介ゲル圧縮およびフィブリン線維再調整を観察し、分析するために使用された。

線維芽細胞媒介フィブリンゲル圧縮の観察と定量

Cells embedded in collagen and fibrin gels attach and exert traction forces on the fibers of the gel. These forces can lead to local and global ...

observing-and-quantifying-fibroblast-mediated-fibrin-gel-compaction

Research

JoVE Journal

Bioengineering

Preparation of Complaint Matrices for Quantifying Cellular Contraction

The regulation of cellular adhesion to the extracellular matrix (ECM) is essential for cell migration and ECM remodeling. Focal adhesions are macromolecular assemblies that couple the contractile F-actin cytoskeleton to the ECM. This connection allows for the transmission of intracellular mechanical forces across the cell membrane to the underlying substrate. Recent work has shown the mechanical properties of the ECM regulate focal adhesion and F-actin morphology as well as numerous physiological processes, including cell differentiation, division, proliferation and migration. Thus, the use of cell culture substrates has become an increasingly prevalent method to precisely control and modulate ECM mechanical properties.
To quantify traction forces at focal adhesions in an adherent cell, compliant substrates are used in conjunction with high-resolution imaging and computational techniques in a method termed traction force microscopy (TFM). This technique relies on measurements of the local magnitude and direction of substrate deformations induced by cellular contraction. In combination with high-resolution fluorescence microscopy of fluorescently tagged proteins, it is possible to correlate cytoskeletal organization and remodeling with traction forces.
Here we present a detailed experimental protocol for the preparation of two-dimensional, compliant matrices for the purpose of creating a cell culture substrate with a well-characterized, tunable mechanical stiffness, which is suitable for measuring cellular contraction. These protocols include the fabrication of polyacrylamide hydrogels, coating of ECM proteins on such gels, plating cells on gels, and high-resolution confocal microscopy using a perfusion chamber. Additionally, we provide a representative sample of data demonstrating location and magnitude of cellular forces using cited TFM protocols.

In this video, we demonstrate the experimental techniques used to fabricate compliant, extracellular matrix (ECM) coated substrates suitable for cell culture, and which are amenable to traction force microscopy and observing effects of ECM stiffness on cell behavior.

細胞収縮を定量化するための苦情の行列の準備

The regulation of cellular adhesion to the extracellular matrix (ECM) is essential for cell migration and ECM remodeling.  Focal adhesions are ...

生物工学

Fabrication of Micro-tissues using Modules of Collagen Gel Containing Cells

This protocol describes the fabrication of a type of micro-tissues called modules.  The module approach generates uniform, scalable and vascularized tissues.  The modules can be made of collagen as well as other gelable or crosslinkable materials.  They are approximately 2 mm in length and 0.7 mm in diameter upon fabrication but shrink in size with embedded cells or when the modules are coated with endothelial cells.  The modules individually are small enough that the embedded cells are within the diffusion limit of oxygen and other nutrients but modules can be packed together to form larger tissues that are perfusable.  These tissues are modular in construction because different cell types can be embedded in or coated on the modules before they are packed together to form complex tissues.  There are three main steps to making the modules: (1) neutralizing the collagen and embedding cells in it, (2) gelling the collagen in the tube and cutting the modules and (3) coating the modules with endothelial cells.

Creation of micro-tissues using cylindrical collagen gels, called modules, that contain embedded cells and which surface is coated with endothelial cells.

コラーゲンゲル含有する細胞のモジュールを使用してマイクロ組織の作製

This protocol describes the fabrication of a type of micro-tissues called modules.  The module approach generates uniform, scalable and vascularized ...

Encapsulation of Cardiomyocytes in a Fibrin Hydrogel for Cardiac Tissue Engineering

Culturing cells in a three dimensional hydrogel environment is an important technique for developing constructs for tissue engineering as well as studying cellular responses under various culture conditions in vitro. The three dimensional environment more closely mimics what the cells observe in vivo due to the application of mechanical and chemical stimuli in all dimensions 1. Three-dimensional hydrogels can either be made from synthetic polymers such as PEG-DA 2 and PLGA 3 or a number of naturally occurring proteins such as collagen 4, hyaluronic acid 5 or fibrin 6,7. Hydrogels created from fibrin, a naturally occurring blood clotting protein, can polymerize to form a mesh that is part of the body's natural wound healing processes 8. Fibrin is cell-degradable and potentially autologous 9, making it an ideal temporary scaffold for tissue engineering.
Here we describe in detail the isolation of neonatal cardiomyocytes from three day old rat pups and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. Neonatal myocytes are a common cell source used for in vitro studies in cardiac tissue formation and engineering 4. Fibrin gel is created by mixing fibrinogen with the enzyme thrombin. Thrombin cleaves fibrinopeptides FpA and FpB from fibrinogen, revealing binding sites that interact with other monomers 10. These interactions cause the monomers to self-assemble into fibers that form the hydrogel mesh. Because the timing of this enzymatic reaction can be adjusted by altering the ratio of thrombin to fibrinogen, or the ratio of calcium to thrombin, one can injection mold constructs with a number of different geometries 11,12. Further we can generate alignment of the resulting tissue by how we constrain the gel during culture 13.
After culturing the engineered cardiac tissue constructs for two weeks under static conditions, the cardiac cells have begun to remodel the construct and can generate a contraction force under electrical pacing conditions 6. As part of this protocol, we also describe methods for analyzing the tissue engineered myocardium after the culture period including functional analysis of the active force generated by the cardiac muscle construct upon electrical stimulation, as well as methods for determining final cell viability (Live-Dead assay) and immunohistological staining to examine the expression and morphology of typical proteins important for contraction (Myosin Heavy Chain or MHC) and cellular coupling (Connexin 43 or Cx43) between myocytes.

We describe the isolation of neonatal cardiomyocytes and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. We describe methods for analyzing the tissue engineered myocardium after the culture period including active force generated upon electrical stimulation and cell viability and immunohistological staining.

心臓組織工学のためのフィブリンゲルにおける心筋細胞のカプセル化

Culturing cells in a three dimensional hydrogel environment is an important technique for developing constructs for tissue engineering as well as studying ...

Preparation of 3D Fibrin Scaffolds for Stem Cell Culture Applications

Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche 1. Culturing stem cells inside of 3D biomaterial scaffolds provides a way to accurately mimic these microenvironments, providing an advantage over traditional 2D culture methods using polystyrene as well as a method for engineering replacement tissues 2. While 2D tissue culture polystrene has been used for the majority of cell culture experiments, 3D biomaterial scaffolds can more closely replicate the microenvironments found in vivo by enabling more accurate establishment of cell polarity in the environment and possessing biochemical and mechanical properties similar to soft tissue.3 A variety of naturally derived and synthetic biomaterial scaffolds have been investigated as 3D environments for supporting stem cell growth. While synthetic scaffolds can be synthesized to have a greater range of mechanical and chemical properties and often have greater reproducibility, natural biomaterials are often composed of proteins and polysaccharides found in the extracelluar matrix and as a result contain binding sites for cell adhesion and readily support cell culture. Fibrin scaffolds, produced by polymerizing the protein fibrinogen obtained from plasma, have been widely investigated for a variety of tissue engineering applications both in vitro and in vivo 4. Such scaffolds can be modified using a variety of methods to incorporate controlled release systems for delivering therapeutic factors 5. Previous work has shown that such scaffolds can be used to successfully culture embryonic stem cells and this scaffold-based culture system can be used to screen the effects of various growth factors on the differentiation of the stem cells seeded inside 6,7.
 This protocol details the process of polymerizing fibrin scaffolds from fibrinogen solutions using the enzymatic activity of thrombin. The process takes 2 days to complete, including an overnight dialysis step for the fibrinogen solution to remove citrates that inhibit polymerization. These detailed methods rely on fibrinogen concentrations determined to be optimal for embryonic and induced pluripotent stem cell culture. Other groups have further investigated fibrin scaffolds for a wide range of cell types and applications - demonstrating the versatility of this approach 8-12.

This work details the preparation of 3D fibrin scaffolds for culturing and differentiating plutipotent stem cells. Such scaffolds can be used to screen the effects of various biological compounds on stem cell behavior as well as modified to contain drug delivery systems.

幹細胞培養アプリケーションのための3Dフィブリン足場の調製

Stem cells are found in naturally occurring 3D microenvironments in vivo, which are often referred to as the stem cell niche 1. Culturing stem cells ...

Engineering Fibrin-based Tissue Constructs from Myofibroblasts and Application of Constraints and Strain to Induce Cell and Collagen Reorganization

Collagen content and organization in developing collagenous tissues can be influenced by local tissue strains and tissue constraint. Tissue engineers aim to use these principles to create tissues with predefined collagen architectures. A full understanding of the exact underlying processes of collagen remodeling to control the final tissue architecture, however, is lacking. In particular, little is known about the (re)orientation of collagen fibers in response to changes in tissue mechanical loading conditions. We developed an in&#160;vitro model system, consisting of biaxially-constrained myofibroblast-seeded fibrin constructs, to further elucidate collagen (re)orientation in response to i) reverting biaxial to uniaxial static loading conditions and ii) cyclic uniaxial loading of the biaxially-constrained constructs before and after a change in loading direction, with use of the Flexcell FX4000T loading device. Time-lapse confocal imaging is used to visualize collagen (re)orientation in a nondestructive manner.
Cell and collagen organization in the constructs can be visualized in real-time, and an internal reference system allows us to relocate cells and collagen structures for time-lapse analysis. Various aspects of the model system can be adjusted, like cell source or use of healthy and diseased cells. Additives can be used to further elucidate mechanisms underlying collagen remodeling, by for example adding MMPs or blocking integrins. Shape and size of the construct can be easily adapted to specific needs, resulting in a highly tunable model system to study cell and collagen (re)organization.

This model system starts from a myofibroblast-populated fibrin gel that can be used to study endogenous collagen (re)organization real-time in a nondestructive manner. The model system is very tunable, as it can be used with different cell sources, medium additives, and can be adapted easily to specific needs.

エンジニアリングフィブリンベースの組織の筋線維芽細胞と制約の適用からの構築と細胞とコラーゲン（再）組織を誘導するためにひずみ

Collagen content and organization in developing collagenous tissues can be influenced by local tissue strains and tissue constraint. Tissue engineers aim ...

Characterization of Leukocyte-platelet Rich Fibrin, A Novel Biomaterial

Autologous platelet concentrates represent promising innovative tools in the field of regenerative medicine and have been extensively used in oral surgery. Unlike platelet rich plasma (PRP) that is a gel or a suspension, Leukocyte-Platelet Rich Fibrin (L-PRF) is a solid 3D fibrin membrane generated chair-side from whole blood containing no anti-coagulant. The membrane has a dense three dimensional fibrin matrix with enriched platelets and abundant growth factors. L-PRF is a popular adjunct in surgeries because of its superior handling characteristics as well as its suturability to the wound bed. The goal of the study is to demonstrate generation as well as provide detailed characterization of relevant properties of L-PRF that underlie its clinical success.

Leucocyte-Platelet Rich Fibrin (L-PRF) represents an FDA cleared preparation of autologous platelet concentrates that possesses unique fibrin architecture, enriched platelets and abundant growth factors. Here, we present a protocol for chair-side generation of L-PRF as well as evaluate its mechanical properties including uniaxial testing and suture retention strength testing.

白血球、血小板リッチフィブリン、新規生体材料の特性評価

Autologous platelet concentrates represent promising innovative tools in the field of regenerative medicine and have been extensively used in oral ...

Forming Giant-sized Polymersomes Using Gel-assisted Rehydration

Polymer vesicles, or polymersomes, are being widely explored as synthetic analogs of lipid vesicles based on their stability, robustness, barrier properties, chemical versatility and tunable physical characteristics. Typical methods used to prepare giant-sized (&gt; 4 &#181;m) vesicles, however, are both time and labor intensive, yielding low numbers of intact polymersomes. Here, we present for the first time the use of gel-assisted rehydration for the rapid and high-yielding formation of giant (&gt;4 &#181;m) polymer vesicles (polymersomes). Using this method, polymersomes can be formed from a wide array of rehydration solutions including several different physiologically-compatible buffers and full cell culture media, making them readily useful for biomimicry studies. This technique is also capable of reliably producing polymersomes from different polymer compositions with far better yields and much less difficulty than traditional methods. Polymersome size is readily tunable by altering temperature during rehydration or adding membrane fluidizers to the polymer membrane, generating giant-sized polymersomes (&gt;100 &#181;m).

We present a protocol to rapidly form giant polymer vesicles (pGVs). Briefly, polymer solutions are dehydrated on dried agarose films adhered to coverslips. Rehydration of the polymer films results in rapid formation of pGVs. This method greatly advances the preparation of synthetic giant vesicles for direct applications in biomimetic studies.

ジェル支援補水を使用した巨大なサイズのポリマーソームを形成します

Polymer vesicles, or polymersomes, are being widely explored as synthetic analogs of lipid vesicles based on their stability, robustness, barrier ...

A Novel Technique for Generating and Observing Chemiluminescence in a Biological Setting

Intraoperative imaging techniques have the potential to make surgical interventions safer and more effective; for these reasons, such techniques are quickly moving into the operating room. Here, we present a new approach that utilizes a technique not yet explored for intraoperative imaging: chemiluminescent imaging. This method employs a ruthenium-based chemiluminescent reporter along with a custom-built nebulizing system to produce ex vivo or in vivo images with high signal-to-noise ratios. The ruthenium-based reporter produces light following exposure to an aqueous oxidizing solution and re-reduction within the surrounding tissue. This method has allowed us to detect reporter concentrations as low as 6.9 pmol/cm2. In this work, we present a visual guide to our proof-of-concept in vivo studies involving subdermal and intravenous injections in mice. The results suggest that this technology is a promising candidate for further preclinical research and might ultimately become a useful tool in the operating room.

This protocol describes a new intraoperative imaging technique that uses a ruthenium complex as a source of chemiluminescent light emission, thereby producing high signal-to-noise ratios during in vivo imaging. Intraoperative imaging is an expanding field that could revolutionize the way that surgical procedures are performed.

生物学的設定における生成と観測化学発光のための新しい技術

Intraoperative imaging techniques have the potential to make surgical interventions safer and more effective; for these reasons, such techniques are ...

A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is restricted to platelet deposition only. The intricate relationship between Ca2+-dependent coagulation and platelet function requires careful and controlled recalcification of blood prior to analysis. Our setup uses a Y-shaped mixing channel, which supplies concentrated Ca2+/Mg2+ buffer to flowing blood just prior to perfusion, enabling rapid recalcification without sample stasis. A ten-fold difference in flow velocity between both reservoirs minimizes dilution. The recalcified blood is then perfused in a collagen-coated analysis chamber, and differential labeling permits real-time imaging of both platelet and fibrin deposition using fluorescence video microscopy. The system uses only commercially available tools, increasing the chances of standardization. Reconstitution of thrombocytopenic blood with platelets from banked concentrates furthermore models platelet transfusion, proving its use in this research domain. Exemplary data demonstrated that coagulation onset and fibrin deposition were linearly dependent on the platelet concentration, confirming the relationship between primary and secondary hemostasis in our model. In a timeframe of 16 perfusion min, contact activation did not take place, despite recalcification to normal Ca2+ and Mg2+ levels. When coagulation factor XIIa was inhibited by corn trypsin inhibitor, this time frame was even longer, indicating a considerable dynamic range in which the changes in the procoagulant nature of the platelets can be assessed. Co-immobilization of tissue factor with collagen significantly reduced the time to onset of coagulation, but not its rate. The option to study the tissue factor and/or the contact pathway increases the versatility and utility of the assay.

This paper describes an experimental model of hemostasis that simultaneously measures platelet function and coagulation. Platelet and fibrin fluorescence is measured in real-time, and platelet adhesion rate, coagulation rate, and onset of coagulation are determined. The model is used to determine platelet procoagulant properties under flow in concentrates for transfusion.

血小板輸血や止血のためのマイクロ流体フローチャンバーモデルは、リアルタイムでの血小板沈着およびフィブリン形成を測定します

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is ...

Gel-seq: A Method for Simultaneous Sequencing Library Preparation of DNA and RNA Using Hydrogel Matrices

The ability to amplify and sequence either DNA or RNA from small starting samples has only been achieved in the last five years. Unfortunately, the standard protocols for generating genomic or transcriptomic libraries are incompatible and researchers must choose whether to sequence DNA or RNA for a particular sample. Gel-seq solves this problem by enabling researchers to simultaneously prepare libraries for both DNA and RNA starting with 100 - 1000 cells using a simple hydrogel device. This paper presents a detailed approach for the fabrication of the device as well as the biological protocol to generate paired libraries. We designed Gel-seq so that it could be easily implemented by other researchers; many genetics labs already have the necessary equipment to reproduce the Gel-seq device fabrication. Our protocol employs commonly-used kits for both whole-transcript amplification (WTA) and library preparation, which are also likely to be familiar to researchers already versed in generating genomic and transcriptomic libraries. Our approach allows researchers to bring to bear the power of both DNA and RNA sequencing on a single sample without splitting and with negligible added cost.

Gel-seq enables researchers to simultaneously prepare libraries for both DNA- and RNA-seq at negligible added cost starting from 100 - 1000 cells using a simple hydrogel device. This paper presents a detailed approach for the fabrication of the device as well as the biological protocol to generate paired libraries.

ゲル-seq: DNA および RNA のゲルのマトリックスを使用しての同時配列ライブラリの準備の方法

The ability to amplify and sequence either DNA or RNA from small starting samples has only been achieved in the last five years. Unfortunately, the ...