この作品は、プラズマ理工学におけるNSF / DOEパートナーシップ（NSFグラント号CBET - 0853777およびDOEグラント番号DE - SC0001169）、STTRフェーズIプロジェクト（NSF STTR PHASE I No.1010133）によってサポートされていました。著者らは、アークの実験をサポートするための核融合エネルギー科学のオフィスによってサポートされているPPPLオフサイトの研究プログラムに感謝します。

1。アノードの準備<ol><li>触媒粉末として4.2:1のモルラジオによると規模ニッケル粉末（99.8％、300メッシュ）とイットリウム粉末（99.9％、40メッシュ）。 </li><li>非常によく黒鉛粉末と触媒粉末（99.9995パーセント、200メッシュ）を混ぜる。しっかりと中空のグラファイト棒（5mmの外径は、2.5内径と75mmの長さ）に混合した粉体を埋める。ニッケル：：アノードロッドのYは94.8:4.2:1場合、SWCNT 9合成する最適な比率であるCの合計モルラジオを確認してください。 </li><li>陰極棒（純粋なグラファイト、13mmの直径）と円筒形のチャンバー内部の詰め物を陽極ロッド（ステンレス製、152 mm径と254 mmの長さ）をインストールします。約3 mmにカソードとアノードとの間のギャップ距離を調整します。 </li></ol> 2。基板のセットアップ<ol><li>電極間軸から約25 mmの距離でチャンバー内の直方体の永久磁石（25ミリメートル× 25ミリメートル× 100 mm）を置きます。使用される超高温度アルニコ磁石実験で650グラムの重量は持っています。電極間ギャップは、永久磁石の底部からH約= 75ミリメートル（ 図1a）の距離に配置された構成を使用してください。 </li><li> 25ミリメートル× 100mmの長方形の形状として0.3mm厚のモリブデンシート（99.95％）カット。 50パーセント超音波処理の振幅、150ワットの出力電力と40 kHzの周波数で30分間アセトンおよびエタノールで超音波dismembratorによる表面汚染を削除します。 </li><li>永久磁石の片側を接続するモリブデンシートをインストールし、電極に向かってこちら側に回します。 </li><li>ガウスメーターにより、電極間ギャップに磁界を測定します。電極間の平均磁界は約0.06 Tの維持</li></ol> 3。アークプラズマの着火<ol><li>圧力未満10 -1 Torrの真空としてヘリウム（99.995パーセント）でそれを埋め〜500 Torrに円筒状のチャンバーをポンプダウン。 </li><li> DC weldiにアーク電極を接続するngの電源と約75 Aの電流をアークに電源を設定する</li><li>アーク電流、アーク電圧とポスト実験解析のためのチャンバ圧力のリアルタイム値を記録します。 </li><li>同時に二つのデジタルカメラで右と正面ビューポートからアークのビデオを始める。弧の1秒は起動後にスナップショットは、 図1bに示すように、（右ビューポートから）と図1d（フロントビューポートから）されています。 </li><li> 15秒間のアークを実行します。少なくとも20分間自然対流によってチャンバを冷やす。 </li></ol> 4。合成後の解析と特性評価<ol><li>アークプラズマジェットが指示されたモリブデンシートの表面から沈着のフレークをティアオフするピンセットを使用してください。別のサンプルは、カソードの黒襟から収集されます。 SEMの下に堆積フレーク（30 KVの加速電圧が使われていた）の両側の形態を観察。 </li><li>のための試料調製に関しては<html> TEM分析、サンプルの薄膜は、50％振幅の超音波処理と超音波dismembratorを使用して60分間超音波処理した後、メタノール分散SWCNTソリューションの懸濁液をキャストしドロップすることによって得られた。メタノール溶液の揮発後に100 KVの電圧でJEOL TEM下で薄膜の形態を観察。試料中の目的の位置については、電子線回折パターンはTEMに関連付けられている50cmのCCDカメラの長さを得ることができます。 </li><li>ラマン分光法は、ホログラフィック光学系、0.5 mの分光器とCCD検出器冷却液体窒素で、200 mWのLexel 3000 Arイオンレーザー（波長可変シングルライン出力）に基づいて、顕微ラマンシステム上で実行され、波長に対応する514 nmの2.33 eVのエネルギー。ラマン測定は、100 cm -1【〜3100 cm -1の範囲をカバーし、グラフェンフレークの表面に実施した。 </li></ol> 5。代表的な結果&quot;チャンバーの右側と正面ビューポートから同時に得られる&gt;ビデオスナップショットを図1bに示されて、時間D = 75 mmである。これらの画像は、軸対称アーク柱と比較して、外部磁界の存在下でアークプラズマ柱の重要な摂動を示しています磁気フィールド10のない場合に観察された。 図2aおよび2bは 、それぞれ、磁場のない陰極の襟にとTEMの下でB = 0.06テスラの磁場で収集したSWCNTや触媒粒子の典型的な形態が表示されます。それは、磁場を持つSWCNTは2〜20 nmのため、個々のSWCNTの間にファンデルワールス相互作用の範囲の直径を持つバンドルに密であることがわかる。比較では、磁場のないSWCNTはバンドルの直径が大きいとラマンスペクトルの解析と一致している大規模な個々の直径を、持っている。また、磁場CA図2a及び2bに示すように、より高い純度を持つSWCNT内のn個の結果。 磁場の中で最も興味深い影響がグラフェン薄片が同じプロセスでモリブデンシートに近い堆積フレークの表面から得られることである。 図2Cおよび2Dは ​​グラフェンフレークのSEMおよびTEM像を示すだけでなく、いくつかの、場所で採取したサンプルから得られた層のグラフェンは、アークプラズマジェットに相当する。 図2dの挿入図は、グラフェンに関連付けられた電子回折パターンを示しています 。電子線回折の六角形のドットパターンは規則正しい結晶構造の証拠を提示。 ラマンスペクトルは、グラフェンのフレークとSWCNTの特性評価のための強力なツールです。グラフェンで観測された典型的なピークは514 nmの励起波長を使用して、〜1600 cm -1にすると-1をそれぞれ〜2700センチメートルでGと2Dのピークです。 Gピークは、すべてのsp2炭素材料で観察することができる面内振動に起因しています。 2Dピークは、四次のフォノンの運動量の交換二重共鳴過程に起因するDピークの二階ですが、さらに非乱れた系で見られている。それは、グラフェンの特性評価において重要な役割を果たしている。私（2D）/ I（G）強度がこういった可能性グラフェン層の厚さを推定すること、それに続く層の追加により、約4単層グラフェンと減少するためである。11 図3は、私の値（2D）ことを示しています/ I（G）は、数層グラフェンの証拠とすることができる、1付近です。 120およびラマンスペクトルに-1 350センチメートルの間にラジアルブリージングモード（RBM）は半径方向のC原子のコヒーレント振動の周波数を通じて、ナノチューブの直径を識別するために使用することができます。周波数とSWCNTの直径の間に実験的な関係は、ωRBMです= A / D T + B、パラメータOバンドル内に形成された典型的なSWCNTのためのそれぞれf Aおよび234と10cm -1に等しいB、、。 図3から、なしと磁場によるSWCNTのRBM周波数は1.52と1.14 nmの平均個々のSWCNTの直径に相当する163.8と215.2センチメートル-1、それぞれです。 <img alt="図1。" src="/files/ftp_upload/3455/3455fig1.jpg" /> 図1。FEMM 4.2ソフトウェアでシミュレート磁場の分布（）、右のビューポート（B）、電極間ギャップが配置されている場合のギャップの電極の位置と方向磁界の模式図から、アークプラズマジェットの写真永久磁石の底部（c）は上記の約75mm、およびアークプラズマの写真正面ビューポート（D）からジェット。 <img alt="図2。" src="/files/ftp_upload/3455/3455fig2.jpg" /> 図2のような合成の代表的なTEM像磁場なしのSWCNTバンドル（）と磁場（B）、磁場（C）、および磁場を持つグラフェンのTEM像と合成されたグラフェン薄片の代表的なSEM像とSWCNTバンドル。挿入図は、グラフェンの結晶構造を示す、選択した領域の電子回折パターンです。 <img alt="図3。" src="/files/ftp_upload/3455/3455fig3.jpg" /> 図3。100〜3100センチメートル-1の範囲の磁場で試料のラマンスペクトル。挿入図：RBM周波数の周りの磁場のない試料のラマンスペクトル。 <img alt="図4。" src="/files/ftp_upload/3455/3455fig4.jpg" /> 図4電極の左側と右側に示すように、炭素とニッケルの密度は、同じ地域で共存している60 Aの注の弧のための炭素とニッケルのナノ構造の成長領域と数密度。

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我々は、開示することは何もない。

電極間ギャップは、永久磁石の底部から約H = 75 mmの距離に配置されている場合のために、 図1bおよび1Dに示すようにビデオのスナップショットでは、磁石の位置の変化が（我々は磁石のシフトをテストすることに留意すべきであるz軸に沿ってと磁石をめくっ） 図1cに示すJ × B力の方向に対応するx方向のアークジェット流れの偏差の結果。また、アークプ...

特定の試薬と機器の表： <table border="1"><tbody><tr><th>試薬の名前</th><th>会社</th><th>カタログ番号</th><th>コメント（省略可能） </th></tr><tr><td>メタノール</td><td>アクロスオーガニック</td><td> 423950010 </td><td></td></tr><tr><td>ニッケルの粉</td><td>アルファAesar </td><td> 10581 </td><td></td></tr><tr><td>イットリウム粉末</td><td>アクロスオーガニック</td><td> 318060050 </td><td></td></tr><tr><td>黒鉛粉末</td><td>アルファAesar </td><td> 40799 </td><td></td></tr><tr><td>中空グラファイトロッド</td><td>土星産業</td><td> POCO EDM 3 </td><td></td></tr><tr><td>永久磁石</td><td>マクマスター、カー</td><td> 57315K51 </td><td></td></tr><tr><td>モリブデン板</td><td> Dingqi科学。とテック。 </td><td> 080504〜11 </td><td></td&gt; </tr><tr><td>超音波 dismembrator </td><td>フィッシャーサイエンティフィック</td><td>モデル150T </td><td></td></tr><tr><td>ホール効果ガウスメーター</td><td> AI </td><td>モデル100 </td><td></td></tr><tr><td>溶接電源</td><td>ミラー電動</td><td>ゴールドスター600SS </td><td></td></tr><tr><td>真空ポンプ</td><td> J / B </td><td> DV - 85N </td><td></td></tr><tr><td> SEM </td><td>ツァイス</td><td> LEO 1430VP </td><td></td></tr><tr><td> TEM </td><td> JEOL </td><td> 1200 EX </td><td></td></tr><tr><td>ラマン</td><td>堀場</td><td> HR800 </td><td></td></tr></tbody></table>

simultaneous synthesis of single-walled carbon nanotubes and graphene in a magnetically-enhanced arc plasma

このような単層カーボンナノチューブ（SWCNT）とグラフェンなどの炭素ナノ構造体は、分子センサー、電界効果トランジスタと超薄型でフレキシブルな電子デバイス1-4の彼らの非常に有望なアプリケーションに、今日のための学者の関心の大洪水を引き付ける。陽極材料の浸食によってサポートされている陽極アーク放電は、比較的高い温度での開発の構造に特有の非平衡過程と炭素材料の高流入を提供することができる最も実用的かつ効率的な方法のいずれか、およびその結果であるとして、合成された製品は、いくつかの構造欠陥とより良い結晶性を持っている。 さらにアーク放電におけるカーボンナノ構造体の合成の制御性と柔軟性を向上させるために、磁場は、アークプラズマの強力な磁気応答に応じて合成プロセス中に適用することができます。それは、磁気強化アークディッシュことが実証されたARGEは、SWCNT 5の平均の長さを増加させる金属触媒粒子とカーボンナノチューブ6の直径分布を狭くし、金属と半導体カーボンナノチューブ7の比率を変更するだけでなく、グラフェン合成8につながることができます。 さらに、それは我々が弧で現在の法線成分と不均一な磁場を導入すると、J × Bの方向に沿ってローレンツ力は、プラズマジェットを生成し、炭素のイオン粒子の効果的な配信を行うことができるマーキングする価値があると試料への熱流束。その結果、大規模なグラフェンのフレークおよび高純度単層カーボンナノチューブは、同時にそのような新しい磁気強化された陽極アーク法によって生成されました。アークイメージングは​​、電子顕微鏡（SEM）走査型、透過型電子顕微鏡（TEM）およびラマン分光法は、カーボンナノ構造体の特性を分析するために用いられた。これらの知見は示しているアークの条件を制御することによりプラズマで生産ナノ構造の特性と操作する機会の広いスペクトル。

Watch this Scientific Journal Video about Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma at JoVE.com

Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma

陽極アーク放電は、種々の炭素ナノ構造体を合成するための最も実用的かつ効率的な方法のひとつです。アークの制御性と柔軟性を高めるために、不均一な磁場が大規模なグラフェンのフレークおよび高純度単層カーボンナノチューブの一段階合成を処理するために導入されました。

磁気強化アークプラズマにおける単層カーボンナノチューブとグラフェンの同時合成

Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very ...

simultaneous-synthesis-single-walled-carbon-nanotubes-graphene

Research

JoVE Journal

Bioengineering

15.2K ビュー.  The George Washington University. 陽極アーク放電は、種々の炭素ナノ構造体を合成するための最も実用的かつ効率的な方法のひとつです。アークの制御性と柔軟性を高めるために、不均一な磁場が大規模なグラフェンのフレークおよび高純度単層カーボンナノチューブの一段階合成を処理するために導入されました。

ビデオ: Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma

Graphene Coatings for Biomedical Implants

Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with nanometer thick layers of graphene for applications as a stent material. Graphene was grown on copper substrates via chemical vapor deposition and then transferred onto nitinol substrates. In order to understand how the graphene coating could change biological response, cell viability of rat aortic endothelial cells and rat aortic smooth muscle cells was investigated. Moreover, the effect of graphene-coatings on cell adhesion and morphology was examined with fluorescent confocal microscopy. Cells were stained for actin and nuclei, and there were noticeable differences between pristine nitinol samples compared to graphene-coated samples. Total actin expression from rat aortic smooth muscle cells was found using western blot. Protein adsorption characteristics, an indicator for potential thrombogenicity, were determined for serum albumin and fibrinogen with gel electrophoresis. Moreover, the transfer of charge from fibrinogen to substrate was deduced using Raman spectroscopy. It was found that graphene coating on nitinol substrates met the functional requirements for a stent material and improved the biological response compared to uncoated nitinol. Thus, graphene-coated nitinol is a viable candidate for a stent material.

Graphene offers potential as a coating material for biomedical implants. In this study we demonstrate a method for coating nitinol alloys with nanometer thick layers of graphene and determine how graphene may influence implant response.

メディカルインプラントのグラフェンコーティング

Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with ...

生物工学

Localization and Relative Quantification of Carbon Nanotubes in Cells with Multispectral Imaging Flow Cytometry

Carbon-based nanomaterials, like carbon nanotubes (CNTs), belong to this type of nanoparticles which are very difficult to discriminate from carbon-rich cell structures and de facto there is still no quantitative method to assess their distribution at cell and tissue levels. What we propose here is an innovative method allowing the detection and quantification of CNTs in cells using a multispectral imaging flow cytometer (ImageStream, Amnis). This newly developed device integrates both a high-throughput of cells and high resolution imaging, providing thus images for each cell directly in flow and therefore statistically relevant image analysis. Each cell image is acquired on bright-field (BF), dark-field (DF), and fluorescent channels, giving access respectively to the level and the distribution of light absorption, light scattered and fluorescence for each cell. The analysis consists then in a pixel-by-pixel comparison of each image, of the 7,000-10,000 cells acquired for each condition of the experiment. Localization and quantification of CNTs is made possible thanks to some particular intrinsic properties of CNTs: strong light absorbance and scattering; indeed CNTs appear as strongly absorbed dark spots on BF and bright spots on DF with a precise colocalization.
This methodology could have a considerable impact on studies about interactions between nanomaterials and cells given that this protocol is applicable for a large range of nanomaterials, insofar as they are capable of absorbing (and/or scattering) strongly enough the light.

In this study, the main purpose was to monitor the cellular uptake and eventual exocytosis of carbon nanotubes (CNTs). From this perspective, we proposed here a unique method using multispectral imaging flow cytometry allowing a quantification and localization of CNTs in a statistically relevant number of cells.

Carbon-based nanomaterials, like carbon nanotubes (CNTs), belong to this type of nanoparticles which are very difficult to discriminate from carbon-rich ...

Synthesis of an Intein-mediated Artificial Protein Hydrogel

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of this hydrogel are two protein block-copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. A highly hydrophilic random coil is inserted into one of the block-copolymers for water retention. Mixing of the two protein block copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit with crosslinkers at either end that rapidly self-assembles into a hydrogel. This hydrogel is very stable under both acidic and basic conditions, at temperatures up to 50 &#176;C, and in organic solvents. The hydrogel rapidly reforms after shear-induced rupture. Incorporation of a &#34;docking station peptide&#34; into the hydrogel building block enables convenient incorporation of &#34;docking protein&#34;-tagged target proteins. The hydrogel is compatible with tissue culture growth media, supports the diffusion of 20 kDa molecules, and enables the immobilization of bioactive globular proteins. The application of the intein-mediated protein hydrogel as an organic-solvent-compatible biocatalyst was demonstrated by encapsulating the horseradish peroxidase enzyme and corroborating its activity.

We present the synthesis of a split-intein-mediated protein hydrogel. The building blocks of this hydrogel are two protein copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. Mixing of the two protein copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit that self-assembles into a hydrogel. This hydrogel is highly pH- and temperature-stable, compatible with organic solvents, and easily incorporates functional globular proteins.

インテイン媒介人工タンパク質ヒドロゲルの合成

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of ...

Synthesis of Keratin-based Nanofiber for Biomedical Engineering

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of these porous nanofibers is of great interest due to their unique physiochemical properties. Here we elaborate on the fabrication of keratin containing poly (&#949;-caprolactone) (PCL) nanofibers (i.e., PCL/keratin composite fiber). Water soluble keratin was first extracted from human hair and mixed with PCL in different ratios. The blended solution of PCL/keratin was transformed into nanofibrous membranes using a laboratory designed electrospinning set up. Fiber morphology and mechanical properties of the obtained nanofiber were observed and measured using scanning electron microscopy and tensile tester. Furthermore, degradability and chemical properties of the nanofiber were studied by FTIR. SEM images showed uniform surface morphology for PCL/keratin fibers of different compositions. These PCL/keratin fibers also showed excellent mechanical properties such as Young&#39;s modulus and failure point. Fibroblast cells were able to attach and proliferate thus proving good cell viability. Based on the characteristics discussed above, we can strongly argue that the blended nanofibers of natural and synthetic polymers can represent an excellent development of composite materials that can be used for different biomedical applications.

Electrospun nanofibers have a high surface area to weight ratio, excellent mechanical integrity, and support cell growth and proliferation. These nanofibers have a wide range of biomedical applications. Here we fabricate keratin/ PCL nanofibers, using the electrospinning technique, and characterize the fibers for possible applications in tissue engineering.

医工学のためのケラチンベースのナノファイバーの合成

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of ...

Engineering Molecular Recognition with Bio-mimetic Polymers on Single Walled Carbon Nanotubes

Semiconducting single-wall carbon nanotubes (SWNTs) are a class of optically active nanomaterial that fluoresce in the near infrared, coinciding with the optical window where biological samples are most transparent. Here, we outline techniques to adsorb amphiphilic polymers and polynucleic acids onto the surface of SWNTs to engineer their corona phases and create novel molecular sensors for small molecules and proteins. These functionalized SWNT sensors are both biocompatible and stable. Polymers are adsorbed onto the nanotube surface either by direct sonication of SWNTs and polymer or by suspending SWNTs using a surfactant followed by dialysis with polymer. The fluorescence emission, stability, and response of these sensors to target analytes are confirmed using absorbance and near-infrared fluorescence spectroscopy. Furthermore, we demonstrate surface immobilization of the sensors onto glass slides to enable single-molecule fluorescence microscopy to characterize polymer adsorption and analyte binding kinetics.

We present a protocol for engineering the corona phase of near infrared fluorescent single walled carbon nanotubes (SWNTs) using amphiphilic polymers and DNA to develop sensors for molecular targets without known recognition elements.

単層カーボンナノチューブ上のバイオミメティックポリマーとエンジニアリング分子認識

Semiconducting single-wall carbon nanotubes (SWNTs) are a class of optically active nanomaterial that fluoresce in the near infrared, coinciding with the ...

Targeted Plasma Membrane Delivery of a Hydrophobic Cargo Encapsulated in a Liquid Crystal Nanoparticle Carrier

The controlled delivery of drug/imaging agents to cells is critical for the development of therapeutics and for the study of cellular signaling processes. Recently, nanoparticles (NPs) have shown significant promise in the development of such delivery systems. Here, a liquid crystal NP (LCNP)-based delivery system has been employed for the controlled delivery of a water-insoluble dye, 3,3&#8242;-dioctadecyloxacarbocyanine perchlorate (DiO), from within the NP core to the hydrophobic region of a plasma membrane bilayer. During the synthesis of the NPs, the dye was efficiently incorporated into the hydrophobic LCNP core, as confirmed by multiple spectroscopic analyses. Conjugation of a PEGylated cholesterol derivative to the NP surface (DiO-LCNP-PEG-Chol) enabled the binding of the dye-loaded NPs to the plasma membrane in HEK 293T/17 cells. Time-resolved laser scanning confocal microscopy and F&#246;rster resonance energy transfer (FRET) imaging confirmed the passive efflux of DiO from the LCNP core and its insertion into the plasma membrane bilayer. Finally, the delivery of DiO as a LCNP-PEG-Chol attenuated the cytotoxicity of DiO; the NP form of DiO exhibited ~30-40% less toxicity compared to DiOfree delivered from bulk solution. This approach demonstrates the utility of the LCNP platform as an efficient modality for the membrane-specific delivery and modulation of hydrophobic molecular cargos.

A liquid crystal nanoparticle (LCNP) nanocarrier is exploited as a vehicle for the controlled delivery of a hydrophobic cargo to the plasma membrane of living cells.

液晶ナノ粒子キャリアにおける疎水性貨物カプセル化の標的細胞膜配達

The controlled delivery of drug/imaging agents to cells is critical for the development of therapeutics and for the study of cellular signaling processes. ...

DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of flexible polymers nor of rigid rods. Underlying filaments remain outstretched due to their non-vanishing backbone stiffness, which is quantified via the persistence length (lp), but they are also subject to strong thermal fluctuations. Their finite bending stiffness leads to unique, non-trivial collective mechanics of bulk networks, enabling the formation of stable scaffolds at low volume fractions while providing large mesh sizes. This underlying principle is prevalent in nature (e.g., in cells or tissues), minimizing the high molecular content and thereby facilitating diffusive or active transport. Due to their biological implications and potential technological applications in biocompatible hydrogels, semiflexible polymers have been subject to considerable study. However, comprehensible investigations remained challenging since they relied on natural polymers, such as actin filaments, which are not freely tunable. Despite these limitations and due to the lack of synthetic, mechanically tunable, and semiflexible polymers, actin filaments were established as the common model system. A major limitation is that the central quantity lp cannot be freely tuned to study its impact on macroscopic bulk structures. This limitation was resolved by employing structurally programmable DNA nanotubes, enabling controlled alteration of the filament stiffness. They are formed through tile-based designs, where a discrete set of partially complementary strands hybridize in a ring structure with a discrete circumference. These rings feature sticky ends, enabling the effective polymerization into filaments several microns in length, and display similar polymerization kinetics as natural biopolymers. Due to their programmable mechanics, these tubes are versatile, novel tools to study the impact of lp on the single-molecule as well as the bulk scale. In contrast to actin filaments, they remain stable over weeks, without notable degeneration, and their handling is comparably straightforward.

Semiflexible polymers display unique mechanical properties that are extensively applied by living systems. However, systematic studies on biopolymers are limited since properties such as polymer rigidity are inaccessible. This manuscript describes how this limitation is circumvented by programmable DNA nanotubes, enabling experimental studies on the impact of filament rigidity.

セミフレキシブル高分子を研究する多目的ツールとして DNA ナノチューブ

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of ...

Melt Electrospinning Writing of Three-dimensional Poly(&#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology with great potential for biomedical applications. The technique facilitates the direct deposition of biocompatible polymer fibers to fabricate well-ordered scaffolds in the sub-micron to micro scale range. The establishment of a stable, viscoelastic, polymer jet between a spinneret and a collector is achieved using an applied voltage and can be direct-written. A significant benefit of a typical porous scaffold is a high surface-to-volume ratio which provides increased effective adhesion sites for cell attachment and growth. Controlling the printing process by fine-tuning the system parameters enables high reproducibility in the quality of the printed scaffolds. It also provides a flexible manufacturing platform for users to tailor the morphological structures of the scaffolds to their specific requirements. For this purpose, we present a protocol to obtain different fiber diameters using melt electrospinning writing (MEW) with a guided amendment of the parameters, including flow rate, voltage and collection speed. Furthermore, we demonstrate how to optimize the jet, discuss often experienced technical challenges, explain troubleshooting techniques and showcase a wide range of printable scaffold architectures.

Melt Electrospinning Writing of Three-dimensional Poly(&amp;#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This protocol serves as a comprehensive guideline to fabricate scaffolds via electrospinning with polymer melts in a direct writing mode. We systematically outline the process and define the appropriate parameter settings for achieving targeted scaffold architectures.

組織工学的応用の制御可能な形態の三次元 Poly(ε-caprolactone) 足場のエレクトロスピニング記述を溶かす

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology ...

Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions

Monolithic honeycomb structures have been attractive to multidisciplinary fields due to their high strength-to-weight ratio. Particularly, microhoneycomb monoliths (MHMs) with micrometer-scale channels are expected as efficient platforms for reactions and separations because of their large surface areas. Up to now, MHMs have been prepared by a unidirectional freeze-drying (UDF) method only from very limited precursors. Herein, we report a protocol from which a series of MHMs consisting of different components can be obtained. Recently, we found that cellulose nanofibers function as a distinct structure-directing agent towards the formation of MHMs through the UDF process. By mixing the cellulose nanofibers with water soluble substances which do not yield MHMs, a variety of composite MHMs can be prepared. This significantly enriches the chemical constitution of MHMs towards versatile applications.

Here, we present a general protocol to prepare a variety of microhoneycomb monoliths (MHMs) in which fluid can pass through with an extremely low pressure drop. MHMs obtained are expected to be used as filters, catalyst supports, flow-type electrodes, sensors and scaffolds for biomaterials.

セルロースナノファイバーの一方向凍結乾燥法により作製した Microhoneycomb モノリス基づくゾル: メソッドと拡張機能

Monolithic honeycomb structures have been attractive to multidisciplinary fields due to their high strength-to-weight ratio. Particularly, microhoneycomb ...

Synthesis of Multi-walled Carbon Nanotubes Modified with Silver Nanoparticles and Evaluation of Their Antibacterial Activities and Cytotoxic Properties

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver MWCNTs were prepared by the reductive deposition of silver from an aqueous solution of AgNO3 on the oxidized MWCNTs. Given the unique color of the CNTs, it was not possible to apply them to the minimum inhibitory concentration or mitochondrial toxicity assays to evaluate the toxicity and antibacterial properties, since they would interfere with the assays. The inhibition zone and minimum bactericidal concentration for the Ag-MWCNTs were measured and Live/Dead and Trypan Blue assays were used to measure the toxicity and antibacterial properties without interfering with the color of the CNTs.

In this study, antimicrobial nanomaterials were synthesized by acidic oxidation of multiwalled carbon nanotubes and subsequent reductive deposition of silver nanoparticles. Antimicrobial activity and cytotoxicity tests were performed with the as-prepared nanomaterials.

銀ナノ粒子とその抗菌活性と細胞毒性の評価変更多層カーボンナノ チューブの合成

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver ...