この作品は、フロリダ国際大学の医工学部門の設備を用いて行った。

1。エレクトロコレクターのセットアップ<ol><li>矩形片にアルミホイルを切った。 </li><li>短冊に矩形片を折るし、テープで平らな金属板（ 図1）に垂直に取り付けます。注：繊維マットの寸法は、ストリップの長さおよび幅に依存する。必要に応じて、このようにして、ストリップの寸法を調整することができる。 </li></ol> 2。高分子溶液の調製<ol><li> PGD​​ポリマーを得100時間、120℃でビーカーに1:1のモル比でグリセロールおよびドデカン二酸（DDA）を混ぜる。 </li><li> 15mlチューブ中の1.5:3:95.5の重量比65％エタノール中でのポリ（エチレンオキシド）（PEO）およびゼラチンを溶解させ、キャップを締めて、撹拌しながら1時間60℃のオーブン中で混合物を加熱それは均一な溶液（基礎溶液）になるまで。 </li><li>エレクトロスピニングの場合は、PGDポリマーと4時06分重量比で、基礎溶液を混合する。注意：PGD濃度は双方向がありグラム繊維径に与える影響。 30％-50％パーセントのPGDはもはや増加しなくなる繊維直径を有する5 cm未満の繊維を製造するのに許容可能である。 </li><li>ポリマー溶液に0.1％のリボフラビンを加え、よく混ぜる。 </li></ol> 3。エレクトロスピニング<ol><li> 18 gの5ミリリットル標準シリンジにポリマー溶液を供給するには、ステンレス製の針を平滑化。 </li><li>シリンジポンプへシリンジを挿入します。 </li><li>金属板への高電圧電源および針に正に荷電リードの接地されたリードを取り付ける。 </li><li> 15センチメートルに針とアルミ箔帯の間の距離を調整します。 </li><li>ストリップの前面に、繊維の凝集を防止するために、水平方向に約15°の角度でシリンジポンプを配置します。 </li><li>シリンジポンプの電源を入れ、0.6ミリリットル/時にポンプの流量を調整します。 </li><li>高電圧電源をオンにして、14.6 kVの動作電圧を設定する。 </li></ol> 4。繊維加工<ol><li>収集が完了すると、架橋のために60分間UV光に繊維マットを露出させる。 </li><li> 100ミリメートルのペトリ皿にアルミ箔ストリップから繊維マットを転送し、殺菌のためさらに20分間UV光にさらす。 </li><li>バイオセーフティキャビネットでは、外科用ブレードを用いて同じ大きさの円形の部分に繊維マットをカットし、24ウェルプレートに作品を配置します。 </li><li>電池プレシーディング処理のために、リン酸緩衝生理食塩水（PBS）1ml中に繊維サンプルを浸漬し、37℃で一晩インキュベートする。 </li><li>翌日、PBSを吸引除去し、慎重に、各ウェルに（材料表内のレシピを参照）を分化培地（DMEM/F12、N2、およびFGF2）の1ミリリットルを加え、3時間37℃でインキュベートする。 </li><li>吸引し分化培地を慎重に、各繊維サンプルに0.2mlのマトリゲルを添加し、30分間37℃でインキュベートする。注：ラミニンはまた、ファイバ被覆のために使用することができる。 20μg/ mlのラミニンの0.2ミリリットルを追加します。ファイバへと3時間室温でインキュベートする。 </li><li>慎重に各ウェルから過剰マトリゲルを削除します。一度分化培地2mlですすいでください。注：繊維試料は、細胞培養の準備ができている。 </li></ol>繊維上5。細胞播種<ol><li>のmES細胞培養皿にして、Accutase 1 mLを加え、37℃で10分間インキュベートする</li><li> 10分後、mES細胞を、培養皿から剥離される。プレートに分化培地4mlを加える。コロニーを破壊するには、上下15ミリリットルチューブとピペット細胞内に浮遊mES細胞を回収（約15倍）。 </li><li>分化培地4ml中の5分間再懸濁細胞を400×gで遠心する。 </li><li>血球計数器を用いて細胞を数える。 15ミリリットルチューブに細胞懸濁液200μlを移すと分化培地で10倍に希釈してください。所定の位置にカバースリップで血球計算板上のチャンバーに希釈した細胞懸濁液15μLを転送します。カウント1ミリメートルの中央広場や顕微鏡下で血球計算板の四隅の正方形のセル。注：ミリリットル当たりの細胞=×10 4希釈倍率X平方あたりの平均回数</li><li>各ウェルに約5×10 4 mES細胞を配置します。ゆっくりと繊維マットを水抜きからソリューションを防ぐために、代わりにほかの側にオフにスライドする、繊維試料の途中に細胞懸濁液をドロップします。 </li><li>各ウェルに分化培地1 mLを加え、37℃のインキュベーターにプレートを保持し、5％CO 2細胞の付着、増殖および分化を可能にする。 </li><li>各ウェルから古い培地を吸引し、一日おきに新鮮な分化培地1mlと交換してください。 </li></ol> 6。細胞生存率<ol><li>各ウェルから古い培地を吸引除去する。 </li><li>培養培地でレサズリン蛍光試薬の1/10の容積を混合し、各ウェルに1ミリリットルを加える。 </li><li> Incub37℃、直接光から保護し、4時間、5％CO 2で食べ。 </li><li> 4時間後、96ウェルプレートに各ウェルから試薬100μlの3倍を転送し、次にサンプルは560EX nm/590EMフィルタ設定を用いた蛍光分光光度計で測定される準備ができている。 </li></ol> 7。リアルタイムPCR <ol><li>培養14日後に、サンプルに溶解緩衝液を追加し、繊維試料上の細胞からトータルRNAを単離する。 </li><li>逆転写により20μlの反応スケールでcDNAを合成した全RNAの4μlを使用する。 </li><li> 10μlのマスターミックス（2×）、0.2μlの染料、8μlのヌクレアーゼフリー水、1μlのcDNA、および1μlのプライマー（本研究で用いたプライマーを表1に示します）：各鏡筒内のPCR反応液を調製する。 </li><li> PCRプログラムをセットアップします。 95℃で2時20分、1サイクルB。 95℃で3秒間→60℃で1分、40サイクルC。 95℃15秒、1サイクルd。 60℃で1分、1サイクルE。 95℃15秒、1サイクル。相対的な遺伝子発現レベルを決定するために、比較C T法を選択する。 </li><li> PCRが終了した後、StepOneソフトウェアでのリアルタイムPCRの結果を分析し、Excelに結果をエクスポート。 </li></ol>

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単純コレクタまたは現在いくつかの用途のための所望の長さおよび繊維マットのサイズを取得する制限を増加させるエレクトロスピニングするために使用されるコレクタを回転させる複雑さの限界。さらに、培養皿または他の基板に接地コレクタから繊維を転送することは挑戦5である。本報告では、接地された集電体にアルミニウム箔ストリップを取り付けることにより簡単に行わ?...

エレクトロスピニングは、マイクロ·ツー·ナノサイズの繊維足場を作製するための効果的な処理方法の一つである。エレクトロスピニングの基本原理は、針の先端と接地されたコレクタとの間に高電圧を印加して、針の開口部に保持される溶液のテーラーコーンを含む。溶液中の静電反発力が表面張力を克服したときに、荷電流体ジェットは、針先端から排出され、溶媒の蒸発と空気を通って移動し、最終的に接地された集電体上に堆積される。シリンジポンプは、紡糸口金から出てくる溶液の連続流を提供し、電界紡糸繊維のこのように複数のコピーが短時間で製造することができる。コレクタに到達するために紡糸口金を出るの過程の間に、帯電したジェットは、ポリマー溶液の粘度及び表面張力を含むパラメータの数、electrostatiに記載の伸縮及び泡立て受けるC溶液の力、及び外部電場との相互作用など2。 電界紡糸プロセスにおいては、集電体は、マイクロ·ツー·ナノファイバーが堆積することができる導電性基板として機能する。本研究では、繊維集新しいタイプの所望のサイズ（長さ×幅）で繊維マットを得るように設計した。伝統的に、アルミニウム箔を集電体として使用されるが、他の基板に平坦な表面から繊維を転送することは困難である。伝統的なコレクタから無傷の繊維マットを収穫することの難しさは、電界紡糸繊維がコレクターの表面に強固に付着するということが主な原因だった。そこで、短冊にアルミニウム箔片を折り畳み、金属平板に垂直に取り付けることによってコレクタを修飾。電界紡糸繊維は、ストリップの先端と簡単に別substratに転送することができる金属板との間の領域にわたって延伸されるE。 熱架橋エラストマーポリマーへの関心が急速にため、ポリ（グリセロールセバケート）（PGS）、2002年3において、加硫ゴムに似ています。PGSと同様にポリエステルを導入しましたロバート·ランガーのグループの先駆的な仕事の成長、私たちが開発に成功しているされているグリセロールおよびドデカン二酸の熱縮合によりポリ（グリセロール-ドデカン）（PGD）とその独特な形状記憶特性1を示した。より硬い合成材料であるポリ（ヒドロキシブチレート）又はポリ（L-ラクチド）（それぞれが250MPaおよび660メガパスカルのヤング率）とは異なり、PGDは、温度が37℃以上である1.08メガパスカルのヤング率を有するゴムのようなエラストマー性を示すその場末梢神経（0.45メガパスカル）に近い試合で、C、。加えて、PGDは、生分解性であり、分解時間は、グリセロールおよびドデカン二酸の比率を変えることによって微調整することができる。ドデカン二酸は12炭素のサブです2端子カルボキシル基、HOOC（CH 2）10 COOHとスタンス。セバシン酸及びドデカン二酸等が偶数番号のジカルボン酸は、アセチル-CoAおよびトリカルボン酸（TCA）/（クエン酸）サイクルを入力するように代謝され得る。ジカルボン酸の代謝産物、スクシニル-CoAは、糖新生前駆体およびTCA回路4の中間体である。したがって、いくつかの研究は、それらが、特に病的状態では、経腸および非経口栄養のための代替燃料の基質として利用できることが示唆された。そのガラス転移温度が31°Cであるため、また、PGD、従ってそれは室温及び体温で異なる機械的性質を示す、ユニークな形状記憶を呈する。要するに、PGDは、神経組織に類似した機械的特性を持つユニークな弾性特性を示す、生分解性、生体適合性である;従って、それは神経組織工学用途に適した材料である。このプロトコルでは、エレクトロ大沈着領域にまたがる長い繊維が、PGDから新設計のコレクタを経由して作製した。ファイバー足場は、マウス多能性幹細胞の増殖および分化を支持することができる。

<table><tbody><tr><td>Glycerol</td><td>Sigma-Aldrich</td><td>G7757</td><td></td></tr><tr><td>Dodecanedioic acid</td><td>Sigma-Aldrich</td><td>D1009</td><td></td></tr><tr><td>Gelatin</td><td>Sigma-Aldrich</td><td>D1890</td><td></td></tr><tr><td>Poly(ethylene oxide) (PEO)</td><td>Sigma-Aldrich</td><td>182028</td><td></td></tr><tr><td>Riboflavin</td><td>Sigma-Aldrich</td><td>132350250</td><td>0.10%</td></tr><tr><td>Mouse embryonic stem cells</td><td>GlobalStem</td><td>GSC-5002</td><td></td></tr><tr><td>Matrigel</td><td>Becton Dickinson</td><td>356234</td><td></td></tr><tr><td>DMEM/F12</td><td>Thermo Scientific</td><td>SH30272.02</td><td></td></tr><tr><td>N2 supplement</td><td>Invitrogen</td><td>17502048</td><td>1%</td></tr><tr><td>FGF2</td><td>Stemgent</td><td>03-0002</td><td>10 ng/ml</td></tr><tr><td>Accutase</td><td>Invitrogen</td><td>A11105-01</td><td></td></tr><tr><td>Phosphate buffered saline (PBS)</td><td>Invitrogen</td><td>10010-031</td><td></td></tr><tr><td>Resazurin fluorescence dye</td><td>Sigma-Aldrich</td><td>62758-13-8</td><td></td></tr><tr><td>SV Total RNA Isolation System</td><td>Promega</td><td>Z3100</td><td></td></tr><tr><td>GoScript Reverse Transcription System</td><td>Promega</td><td>A5000</td><td></td></tr><tr><td>GoTaq qPCR Master Mix</td><td>Promega</td><td>A6001</td><td></td></tr><tr><td>Syringe pump&amp;nbsp;</td><td>Fisher scientific</td><td>14-831-200</td><td></td></tr><tr><td>High voltage power source&amp;nbsp;</td><td>Spellman High Voltage Electronics Corporation</td><td></td><td>SL30</td></tr><tr><td>UV light</td><td>Philips</td><td>308643</td><td>15W/G15T8</td></tr><tr><td>Synergy HT Multi-Mode Microplate Reader</td><td>BioTek</td><td></td><td></td></tr><tr><td>Perkin Elmer GeneAmp PCR System 9600</td><td>Perkin Elmer</td><td>8488</td><td></td></tr><tr><td>StepOne Real-time PCR System</td><td>Applied Biosystems</td><td>4376357</td><td></td></tr></tbody></table>

electrospun fibrous scaffolds of poly(glycerol-dodecanedioate) for engineering neural tissues from mouse embryonic stem cells

組織工学用途のために、生分解性および生体適合性の足場の調製は、最も望ましいが困難なタスクである。様々な製造方法の中で、エレクトロスピニングは、そのシンプルさと汎用性に最も魅力の一つです。さらに、電界紡糸ナノ繊維は、細胞の生存および増殖のための追加の支持を確保する天然の細胞外マトリックスのサイズを模倣する。本研究では、エレクトロスピニングのために新たに設計されたコレクタを使用してポリ（グリセロール-ドデカン）（PGD）1という名前の新 ​​たな生分解性と生体適合性ポリマーのためのより大きな沈着領域にまたがる長繊維の製造の実現可能性を示した。 PGD​​は、従って、それが神経組織工学用途に適している、神経組織と同様の機械的特性を有する独特の弾性特性を呈する。繊維性足場材料を製造するための合成および製作のセットアップは、簡単で再現性の高い、安価であった。生体適合性に試験、マウスの胚性幹細胞由来の細胞はに付着し、エレクトロスピニングPGD繊維上で成長できた。要するに、このプロトコルは、マウス胚性幹細胞由来の神経系細胞の増殖を支持するためにPGDの電界紡糸繊維を製造するための多用途の製造方法を提供した。

エレクトロスピニングの主要なコンポーネントが図1に示されている。大型繊維マットは、典型的には、垂直に取り付けられたアルミニウム箔ストリップと金属平板を介して得た。 図2は、集電体の設計および電気紡糸繊維マットを示す。幅及び長さは、異なる用途のために調整することができる。 PGD​​ポリマーおよび基底溶液混合物で作られた繊維の長さは10cmま?...

Watch this Scientific Journal Video about Electrospun Fibrous Scaffolds of Polyglycerol-dodecanedioate for Engineering Neural Tissues From Mouse Embryonic Stem Cells at JoVE.com

Electrospun Fibrous Scaffolds of Polyglycerol-dodecanedioate for Engineering Neural Tissues From Mouse Embryonic Stem Cells

ポリ（グリセロール - ドデカン）という小説の生分解性ポリマーから新たに設計されたコレクタを経由して、より大きな沈着領域にまたがるエレクトロ長繊維（PGD）の合成及び製造が報告された。繊維は、マウス多能性幹細胞に由来する細胞の増殖を支持することができた。

マウス胚性幹細胞からの神経組織エンジニアリングのためのポリエレクトロ繊維状足場（グリセロール - ドデカン）

For tissue engineering applications, the preparation of biodegradable and biocompatible scaffolds is the most desirable but challenging task. &#160;Among ...

electrospun-fibrous-scaffolds-poly-glycerol-dodecanedioate-for

Research

JoVE Journal

Bioengineering

Electrospun Fibrous Scaffolds of Poly(glycerol-dodecanedioate) for Engineering Neural Tissues From Mouse Embryonic Stem Cells

10.8K ビュー.  Florida International University. ポリ（グリセロール - ドデカン）という小説の生分解性ポリマーから新たに設計されたコレクタを経由して、より大きな沈着領域にまたがるエレクトロ長繊維（PGD）の合成及び製造が報告された。繊維は、マウス多能性幹細胞に由来する細胞の増殖を支持することができた。 

ビデオ: Electrospun Fibrous Scaffolds of Polyglycerol-dodecanedioate for Engineering Neural Tissues From Mouse Embryonic Stem Cells

The Culture of Primary Motor and Sensory Neurons in Defined Media on Electrospun Poly-L-lactide Nanofiber Scaffolds

Electrospinning is a technique for producing micro- to nano-scale fibers. Fibers can be electrospun with varying degrees of alignment, from highly aligned to completely random. In addition, fibers can be spun from a variety of materials, including biodegradable polymers such as poly-L-lactic acid (PLLA). These characteristics make electrospun fibers suitable for a variety of scaffolding applications in tissue engineering. Our focus is on the use of aligned electrospun fibers for nerve regeneration. We have previously shown that aligned electrospun PLLA fibers direct the outgrowth of both primary sensory and motor neurons in vitro. We maintain that the use of a primary cell culture system is essential when evaluating biomaterials to model real neurons found in vivo as closely as possible. Here, we describe techniques used in our laboratory to electrospin fibrous scaffolds and culture dorsal root ganglia explants, as well as dissociated sensory and motor neurons, on electrospun scaffolds. However, the electrospinning and/or culture techniques presented here are easily adapted for use in other applications.

Aligned electrospun fibers direct the growth of neurons in vitro and are a potential component of nerve regeneration scaffolds. We describe a procedure for preparing electrospun fiber substrates and the serum-free culture of primary rat E15 sensory (DRG) and motor neurons. Visualization of neurons by immunocytochemistry is also included.

一次運動とエレクトロポリ- L -乳酸ナノファイバー足場上で定義されているメディアの感覚ニューロンの文化

Electrospinning is a technique for producing micro- to nano-scale fibers. Fibers can be electrospun with varying degrees of alignment, from highly aligned ...

神経科学

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 ...

生物工学

Cultivation of Human Neural Progenitor Cells in a 3-dimensional Self-assembling Peptide Hydrogel

The influence of 3-dimensional (3D) scaffolds on growth, proliferation and finally neuronal differentiation is of great interest in order to find new methods for cell-based and standardised therapies in neurological disorders or neurodegenerative diseases. 3D structures are expected to provide an environment much closer to the in vivo situation than 2D cultures. In the context of regenerative medicine, the combination of biomaterial scaffolds with neural stem and progenitor cells holds great promise as a therapeutic tool.1-5 Culture systems emulating a three dimensional environment have been shown to influence proliferation and differentiation in different types of stem and progenitor cells. Herein, the formation and functionalisation of the 3D-microenviroment is important to determine the survival and fate of the embedded cells.6-8 Here we used PuraMatrix9,10 (RADA16, PM), a peptide based hydrogel scaffold, which is well described and used to study the influence of a 3D-environment on different cell types.7,11-14 PuraMatrix can be customised easily and the synthetic fabrication of the nano-fibers provides a 3D-culture system of high reliability, which is in addition xeno-free.
Recently we have studied the influence of the PM-concentration on the formation of the scaffold.13 In this study the used concentrations of PM had a direct impact on the formation of the 3D-structure, which was demonstrated by atomic force microscopy. A subsequent analysis of the survival and differentiation of the hNPCs revealed an influence of the used concentrations of PM on the fate of the embedded cells. However, the analysis of survival or neuronal differentiation by means of immunofluorescence techniques posses some hurdles. To gain reliable data, one has to determine the total number of cells within a matrix to obtain the relative number of e.g. neuronal cells marked by &beta;III-tubulin. This prerequisites a technique to analyse the scaffolds in all 3-dimensions by a confocal microscope or a comparable technique like fluorescence microscopes able to take z-stacks of the specimen. Furthermore this kind of analysis is extremely time consuming. 
Here we demonstrate a method to release cells from the 3D-scaffolds for the later analysis e.g. by flow cytometry. In this protocol human neural progenitor cells (hNPCs) of the ReNcell VM cell line (Millipore USA) were cultured and differentiated in 3D-scaffolds consisting of PuraMatrix (PM) or PuraMatrix supplemented with laminin (PML). In our hands a PM-concentration of 0.25% was optimal for the cultivation of the cells13, however the concentration might be adapted to other cell types.12 The released cells can be used for e.g. immunocytochemical studies and subsequently analysed by flow cytometry. This speeds up the analysis and more over, the obtained data rest upon a wider base, improving the reliability of the data.

Here we describe the use of a self-assembling 3-dimensional scaffold to culture human neural progenitor cells. We present a protocol to release the cells from the scaffolds to be analysed subsequently e.g. by flow cytometry. This protocol might be adapted to other cell types to perform detailed mechanistically studies.

3次元自己組織化ペプチドハイドロゲル中のヒト神経前駆細胞の栽培

The  influence of 3-dimensional (3D) scaffolds on growth, proliferation and finally  neuronal differentiation is of great interest in order to find new ...

Electrospinning Growth Factor Releasing Microspheres into Fibrous Scaffolds

This procedure describes a method to fabricate a multifaceted substrate to direct nerve cell growth. This system incorporates mechanical, topographical, adhesive and chemical signals. Mechanical properties are controlled by the type of material used to fabricate the electrospun fibers. In this protocol we use 30% methacrylated Hyaluronic Acid (HA), which has a tensile modulus of ~500 Pa, to produce a soft fibrous scaffold. Electrospinning on to a rotating mandrel produces aligned fibers to create a topographical cue. Adhesion is achieved by coating the scaffold with fibronectin. The primary challenge addressed herein is providing a chemical signal throughout the depth of the scaffold for extended periods. This procedure describes fabricating&#160;poly(lactic-co-glycolic acid) (PLGA) microspheres that contain Nerve Growth Factor (NGF) and directly impregnating the scaffold with these microspheres during the electrospinning process. Due to the harsh production environment, including high sheer forces and electrical charges, protein viability is measured after production. The system provides protein release for over 60 days and has been shown to promote primary nerve cell growth.

This protocol combines electrospinning and microspheres to develop tissue engineered scaffolds to direct neurons. Nerve growth factor was encapsulated within PLGA microspheres and electrospun into Hyaluronic Acid (HA) fibrous scaffolds. The protein bioactivity was tested by seeding the scaffolds with primary chick Dorsal Root Ganglia and culturing for 4-6 days.

繊維状足場に微小球を離すエレクトロ成長因子

This procedure describes a method to fabricate a multifaceted substrate to direct nerve cell growth.  This system incorporates mechanical, topographical, ...

Electrospun Nanofiber Scaffolds with Gradations in Fiber Organization

The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible applications in controlling cell morphology/orientation. Nanofiber organization is controlled with a new fabrication apparatus that enables the gradual decrease of fiber organization in a scaffold. Changing the alignment of fibers is achieved through decreasing deposition time of random electrospun fibers on a uniaxially aligned fiber mat. By covering the collector with a moving barrier/mask, along the same axis as fiber deposition, the organizational structure is easily controlled. For tissue engineering purposes, adipose-derived stem cells can be seeded to these scaffolds. Stem cells undergo morphological changes as a result of their position on the varied organizational structure, and can potentially differentiate into different cell types depending on their locations. Additionally, the graded organization of fibers enhances the biomimicry of nanofiber scaffolds so they more closely resemble the natural orientations of collagen nanofibers at tendon-to-bone insertion site compared to traditional scaffolds. Through nanoencapsulation, the gradated fibers also afford the possibility to construct chemical gradients in fiber scaffolds, and thereby further strengthen their potential applications in fast screening of cell-materials interaction and interfacial tissue regeneration. This technique enables the production of continuous gradient scaffolds, but it also can potentially produce fibers in discrete steps by controlling the movement of the moving barrier/mask in a discrete fashion.

Here, we present a protocol to fabricate electrospun nanofiber scaffolds with gradated organization of fibers and explore their applications in regulating cell morphology/orientation. Gradients with regard to physical and chemical properties of the nanofiber scaffolds offer a wide variety of applications in the biomedical field.

繊維組織における階調の電界紡糸ナノファイバー足場

The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible ...

Engineered 3D Silk-collagen-based Model of Polarized Neural Tissue

Despite huge efforts to decipher the anatomy, composition and function of the brain, it remains the least understood organ of the human body. To gain a deeper comprehension of the neural system scientists aim to simplistically reconstruct the tissue by assembling it in vitro from basic building blocks using a tissue engineering approach. Our group developed a tissue-engineered silk and collagen-based 3D brain-like model resembling the white and gray matter of the cortex. The model consists of silk porous sponge, which is pre-seeded with rat brain-derived neurons, immersed in soft collagen matrix. Polarized neuronal outgrowth and network formation is observed with separate axonal and cell body localization. This compartmental architecture allows for the unique development of niches mimicking native neural tissue, thus enabling research on neuronal network assembly, axonal guidance, cell-cell and cell-matrix interactions and electrical functions.

Insight into the complex actions of the brain requires advanced research tools. Here we demonstrate a novel silk-collagen-based 3D engineered model of neural tissue resembling brain-like architecture. The model can be used to study neuronal network assembly, axonal guidance, cell-cell interactions and electrical activity.

偏神経組織のエンジニア3Dシルクコラーゲンベースモデル

Despite huge efforts to decipher the anatomy, composition and function of the brain, it remains the least understood organ of the human body. To gain a ...

Electrospinning Fibrous Polymer Scaffolds for Tissue Engineering and Cell Culture

As the field of tissue engineering evolves, there is a tremendous demand to produce more suitable materials and processing techniques in order to address the requirements (e.g., mechanics and vascularity) of more intricate organs and tissues. Electrospinning is a popular technique to create fibrous scaffolds that mimic the architecture and size scale of the native extracellular matrix. These fibrous scaffolds are also useful as cell culture substrates since the fibers can be used to direct cellular behavior, including stem cell differentiation (see extensive reviews by Mauck et al. and Sill et al. for more information). In this article, we describe the general process of electrospinning polymers and as an example, electrospin a reactive hyaluronic acid capable of crosslinking with light exposure (see Ifkovits et al. for a review on photocrosslinkable materials). We also introduce further processing capabilities such as photopatterning and multi-polymer scaffold formation. Photopatterning can be used to create scaffolds with channels and multi-scale porosity to increase cellular infiltration and tissue distribution. Multi-polymer scaffolds are useful to better tune the properties (mechanics and degradation) of a scaffold, including tailored porosity for cellular infiltration. Furthermore, these techniques can be extended to include a wide array of polymers and reactive macromers to create complex scaffolds that provide the cues necessary for the development of successful tissue engineered constructs.

The process of electrospinning polymers for tissue engineering and cell culture is addressed in this article. Specifically, the electrospinning of photoreactive macromers with additional processing capabilities of photopatterning and multi-polymer electrospinning is described.

組織工学と細胞培養のための繊維状重合体の足場をエレクトロ

As the field of tissue engineering evolves, there is a tremendous demand to produce more suitable materials and processing techniques in order to address ...

生物学

Electrically Conductive Scaffold to Modulate and Deliver Stem Cells

Stem cell therapy has emerged as an exciting stroke therapeutic, but the optimal delivery method remains unclear. While the technique of microinjection has been used for decades to deliver stem cells in stroke models, this technique is limited by the lack of ability to manipulate the stem cells prior to injection. This paper details a method of using an electrically conductive polymer scaffold for stem cell delivery. Electrical stimulation of stem cells using a conductive polymer scaffold alters the stem cell's genes involved in cell survival, inflammatory response, and synaptic remodeling. After electrical preconditioning, the stem cells on the scaffold are transplanted intracranially in a distal middle cerebral artery occlusion rat model. This protocol describes a powerful technique to manipulate stem cells via a conductive polymer scaffold and creates a new tool to further develop stem cell-based therapy.

This protocol describes fabrication of a cell culture system to allow seeding of stem cells on a conductive polymer scaffold for in vitro electrical stimulation and subsequent in vivo implantation of the stem cell-seeded scaffold using a minimally invasive technique.

導電性足場を調節して幹細胞を提供するには

Stem cell therapy has emerged as an exciting stroke therapeutic, but the optimal delivery method remains unclear. While the technique of microinjection ...

Anatomically Inspired Three-dimensional Micro-tissue Engineered Neural Networks for Nervous System Reconstruction, Modulation, and Modeling

Functional recovery rarely occurs&#160;following injury or disease-induced degeneration within the central nervous system (CNS)&#160;due to the inhibitory environment and the limited capacity for neurogenesis. We are developing&#160;a strategy to simultaneously address&#160;neuronal and axonal pathway loss within the damaged CNS. This manuscript presents the fabrication protocol for micro-tissue engineered neural networks (micro-TENNs), implantable constructs consisting of neurons and aligned axonal tracts spanning the extracellular matrix (ECM) lumen of a preformed hydrogel cylinder hundreds of microns in diameter that may extend centimeters in length. Neuronal aggregates are delimited to the extremes of the three-dimensional encasement and are spanned by axonal projections. Micro-TENNs are uniquely poised as a strategy for CNS reconstruction, emulating aspects of brain connectome cytoarchitecture and potentially providing means for network replacement. The neuronal aggregates may synapse with host tissue to form new functional relays to restore and/or modulate missing or damaged circuitry. These constructs may also act as pro-regenerative&#160;&#34;living scaffolds&#34; capable of exploiting developmental mechanisms for cell migration and axonal pathfinding, providing synergistic structural and soluble cues based on the state of regeneration. Micro-TENNs are fabricated by pouring liquid hydrogel into a cylindrical mold containing a longitudinally centered needle. Once the hydrogel has gelled, the needle is removed, leaving a hollow micro-column. An ECM solution is added to the lumen to provide an environment suitable for neuronal adhesion and axonal outgrowth. Dissociated neurons are mechanically aggregated for precise seeding within one or both ends of the micro-column. This methodology reliably produces self-contained miniature constructs with long-projecting axonal tracts that may recapitulate features of brain neuroanatomy. Synaptic immunolabeling and genetically encoded calcium indicators suggest that micro-TENNs possess extensive synaptic distribution and intrinsic electrical activity. Consequently, micro-TENNs represent a promising strategy for targeted neurosurgical reconstruction of brain pathways and may also be applied as biofidelic models to study neurobiological phenomena in vitro.

This manuscript details the fabrication of micro-tissue engineered neural networks: three-dimensional micron-sized constructs comprised of long aligned axonal tracts spanning aggregated neuronal population(s) encased in a tubular hydrogel. These living scaffolds can serve as functional relays to reconstruct or modulate neural circuitry or as biofidelic test-beds mimicking gray-white matter neuroanatomy.

神経系の再構築、変調、モデリングのための解剖学的にインスパイアされた3次元マイクロ組織工学ニューラルネットワーク

Functional recovery rarely occurs&#160;following injury or disease-induced degeneration within the central nervous system (CNS)&#160;due to the inhibitory ...

Controlling Electrospun Polymer Morphology for Tissue Engineering Demonstrated Using hepG2 Cell Line

Electrospinning affords researchers the opportunity to fabricate reproducible micro to nanoscale polymer fibers. The 3D fibrous architecture of electrospun polymers is regarded as a structural imitation of the extracellular matrix (ECM). Hence, electrospun fibers fabricated from biocompatible polymers have been widely investigated by tissue engineering researchers for their potential role as an artificial ECM for guiding tissue growth both in vitro and in vivo. All cells are acutely sensitive to their mechanical environment. This has been demonstrated by the discovery of multiple mechanotransduction pathways intrinsically linked to the cytoskeletal actin filaments. The cytoskeleton acts as a mechanical sensor that can direct the functionality and differentiation of the host cell depending on the stiffness and morphology of its substrate. Electrospun fibers can be tuned both in terms of fiber size and morphology to easily modulate the mechanical environment within a fibrous polymer scaffold. Here, methods for electrospinning polycaprolactone (PCL) for three distinct morphologies at two different fiber diameters are described. The morphological fiber categories consist of randomly oriented fibers, aligned fibers, and porous cryogenically spun fibers, with 1 &#181;m and 5 &#181;m diameters. The methods detailed within this study are proposed as a platform for investigating the effect of electrospun fiber architecture on tissue generation. Understanding these effects will allow researchers to optimize the mechanical properties of electrospun fibers and demonstrate the potential of this technology more thoroughly.

This method provides the means to test different polycaprolactone fiber morphologies and topographies for the purpose of tissue engineering. Small and large fibers are fabricated with random orientations, aligned orientations, and also porous cryogenically electrospun structures and used as platforms for cell culture.