This work is partially supported by NSF (DMR-1006870) and NASA (NASA-NNX13AQ60G). X. Z. Wang acknowledges support from the Mary Kay O'Connor Process Safety Center (MKOPSC) at Texas A&amp;M University. We also thank Min Shuai for her guidance.

水熱合成法を用いたα-ZrPの1.合成<ol><li>塩化ジルコニル八水和物（のZrOCl 2・8H 2 O）150ミリリットル丸底フラスコ内の脱イオン3.75ミリリットル（DI）中の水の6グラムを溶かします。 </li><li>激しく攪拌しながら脱イオン（DI）水8.25 mlで添加すること、続いて、ステップ1.1で調製したのZrOCl 2溶液に15 Mリン酸（H 3 PO 4）を滴下し、48 mLを加え。 </li><li> 80ミリリットルの容量のテフロンでライニング圧力容器内にゲル状の混合物を生じた注ぎます。ステンレス鋼殻と蓋、圧力プレートで構成される熱水オートクレーブ内に容器を配置し、うまく締めます。 </li><li> 24時間200℃の対流式オーブンの中に水熱オートクレーブを置きます。 </li><li>反応後、水熱オートクレーブは周囲の冷却下、室温に8時間を冷却することができます。 </li><li> 2で遠心分離機を用いて冷却した後、遠心分離管中のα-ZrPのディスクを収集し、10分間、500×gで。上澄み液は腐食性のある未反応のリン酸を含有しているので廃棄物処理容器内の液体部分を収集します。 <ol><li>その後、再び10分間、2500×gで1分間遠心のための渦-のZrPをαに水40mlを加えます。酸のすべてが洗い流されることを確実にするために、この手順を3回繰り返します。 </li></ol></li><li> 8時間、65℃のオーブンで乾燥したZrP-水粘着性混合した後、乳棒と乳鉢を用いて、それを挽きます。 </li></ol>逆流法によるα-ZrPの2.合成<ol><li> 150ミリリットル丸底フラスコ中で50ミリリットルM 12のリン酸とのZrOCl 2の6グラム・8H 2 Oを混ぜます。 </li><li>ステップ2.1で調製した混合物を24時間94℃の油浴中で還流します。 </li><li>ステップ1.6において同じプロトコルに従って脱イオン水で3回、生成物を洗浄し、次いで、8時間65℃のオーブン中で乾燥させました。 </li><li>グラインドは乳棒と乳鉢を用いて粉末にかさばるサンプルを乾燥させ、株式F以降を使用。 </li></ol>マイクロ波アシスト法によるα-ZrPを3.合成<ol><li> 12 Mリン酸溶液の9ミリリットルへのZrOCl 2・8H 2 Oの1グラムを追加し、20ミリリットルのシンチレーションバイアル中でも、得られた混合物を攪拌。 </li><li>マイクロ波反応器に指定された10mlのガラス容器に上記混合物を5ml注ぎます。 </li><li> 150℃の反応温度を設定する300 psiの圧力限界、反応物を1時間にわたって起こることを可能にします。 </li><li>反応後、ガラス容器を約15分間冷却した後、α-ZrPの結晶の酸洗浄、乾燥のための手順1.6から1.7と同じ手順に従ってみましょう。 </li></ol>単分子膜への層状α-ZrPを4.剥離<ol><li> 20mLのシンチレーションバイアル中で脱イオン水10ml中にα-ZrPの1gを分散させます。 </li><li>それにTBAOHの2.2ミリリットル（40重量％）を追加して、少なくとも40秒間ボルテックス。 Zrとのモル比に注目してください：1：TBAOHを1として保持されます。 </li><li> 1-2時間のために、得られた濃縮懸濁液を超音波処理し、TBA +イオンと結晶の完全な剥離の完全なインターカレーションを可能にするために、3日間のまま。任意に、濃縮された懸濁液は、より良好な剥離を得るために水（2〜3倍希釈）に希釈することができます。 </li><li>底に沈降し、部分的に剥離した結晶を除去するために、1時間高速回転（2500 XG）で剥離したサンプルを遠心します。別の容器に（ZrPの剥離）上部を収集し、何の沈殿物が見つからなくなるまで手順を繰り返します。 </li></ol>

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There is nothing to disclose.

還流法は、均一な直径と厚さのα-ZrPのの小さいサイズを作るための良いオプションです。水熱合成法と同様に、還流法は、準備時間によって制限されます。一般に、結晶が成長するための時間がかかります。 還流法に必要な長い反応時間は、より大きなサイズを有するナノディスクをもたらすことができます。剥離したナノディスクの平均サイズは、動的光散乱（DLS）によって測定されます。本研究では、剥離したZrPナノディスクのサイズは、19.6％の多分散性を持つ1021.5 nmで、7.0％の多分散性を持つ289.8 nmで、水熱法（12 MH 3 PO 4、24時間）、還流法のための19.1％の多分散性を持つ477.5 nmの（12ありますH 3 PO 4、24時間）及びマイクロ波支援合成（15 H 3 PO 4、1時間）。我々はまた、HシータたZrP（θ-たZrP）、還流法はZrPの異なる位相を合成するために使用することができることを見出しました大きな層間間隔は、混合手順及び材料の濃度を変化させることにより、-たZrPをαと比較して。例えば、平均120nmの大きさと、12ナノメートルの厚さθ-たZrPディスクはのZrOCl 2 15の希釈液中に35重量％のH 3 PO 4を滴下始まる還流法によって調製しました。均一なα-ZrPのナノディスクを得るために、合成手順中の最も重要なステップは、前駆体のすべてが十分に混合されることを保証することです。リン酸のZrOCl 2溶液に導入されると、ゲルはすぐに攪拌せずに形成されます。ゲルの存在は、低結晶性の不均一なナノディスクまたはナノディスクになります。 マイクロ波支援方法は、ナノ材料の合成のための新しい技術です。 ZrPの手順の一般的なマイクロ波支援合成では、水を効率的にすることができる媒体マイクロ波吸収体8として機能しますマイクロ波エネルギーを熱に変換します。水分子は、マイクロ波により照射されるとき、水分子中の双極子は、それに応じて適用される電磁場を用いて自分自身を整列する傾向があります。その結果、誘電加熱と水分子との間の摩擦からのエネルギーは熱として放出されます。したがって、熱が内部で生成され、従来のオーブン内で行われる外部の熱伝達よりも効率的です。マイクロ波支援方法では、比較的低い反応温度（150℃）及びより短い反応時間（10分及び60分）は、α-ZrPの所望の大きさをもたらすことが見出されています。 剥離したZrPナノディスクの液晶相が原因異方性の高い（サイズ比に厚さが非常に小さい）自然とナノディスクとの間の静電相互作用の興味深いものです。ネマチック転移の等方性は、高い異方性のZrPの非常に低い体積分率で観察されます。ネマチックタクトイドは重力に成長し、落ち着く、核形成します。 ASA結果は、ネマチック相を、 図4に見られるように底部に形成されている。重力の長期効果は、現在、我々の研究室で研究されている結晶の圧縮を引き起こします。表面上の電荷のために、ナノディスクとの間の静電相互作用は、ナノディスクの自己集合を決定する上で重要な役割を果たす。天然に豊富なナノディスクの完全な相図は、まだ完全には理解されるべきです。液晶相11の形成に加えて、たZrPは、薬物送達15の潜在的な用途を有します。単層のZrPは、このような薄膜16としてナノコンポジットのためのナノディスクとして良い候補です。

円盤状コロイド粘土、アスファルテン、赤血球、及び真珠層の形で天然に豊富です。ポリマーナノコンポジット1、バイオミメティック材料、機能性膜2、ディスコティック液晶の研究3および4は 、円盤状のコロイドナノディスクに基づいて開発されたピッカリングエマルション安定剤を含む多くの工学的システムでのアプリケーションの範囲。均一性と低い多分散性を有するナノディスクは、液晶の位相と変換を研究するために重要です。リン酸ジルコニウム（ZrPのは）整然とした層構造と制御可能なアスペクト比（直径以上の厚さ）を有する合成ナノディスクです。したがって、ZrPのの異なる合成の探査は、ディスコティック液晶システムの基本的な理解を確立するのに役立ちます。 ZrPのの構造は、1964年5でクリアフィールドとStynes ​​によって明らかにされた。たZrPの層状結晶の合成のために、熱水と逆流の方法は、一般的に6,7を採用しています。還流法が同じ持続時間のためのより小さな結晶を与えながら、水熱法は、400から25％6内の1500 nmおよび多分散性に至るまでのサイズに良好な制御を提供します。マイクロ波加熱は、ナノ材料8の合成のための有望な方法であることが証明されています。しかし、マイクロ波支援経路に基づいてのZrPの合成を記載ない論文はありません。サイズ、アスペクト比、水熱法による結晶成長の機構上の効果的な制御を系統的我々のグループ6で検討しました。 ZrPのは、簡単に、水性懸濁液中で単層に剥離することができ、剥離したZrPはよくチェンのグループ3,9-13に液晶材料として確立されています。これまで、様々な直径を持つ剥離したZrPナノディスクは、異なるアスペクト比が大きいのZrPが低いコンでI（等方性）-N（ネマチック）移行を持っていたと結論するために研究されてきた、と言います小さ ​​いZrPの3に比べてセンタリング。多分散度3は 、ネマチック液晶相の形成の塩9及び温度10,11効果も検討されています。また、このような警告となる液晶相などの他の相は、同様に13,14が検討されています。 この記事では、このようなコロイド状のZrPナノディスクサスペンションの実験的な実現を示しています。層状たZrP結晶は、異なる方法を介して合成され、その後、単層ナノディスクを得るために、水性媒体中で剥離されます。最後に、我々は、このシステムが示す液晶相転移を示します。これらのディスクの注目すべき側面は、直径比の厚さは0.0007ディスク3の大きさに応じて0.05の範囲にあることを、それらの非常に異方性です。異方性の高い単層のナノディスクは、ナノディスクの懸濁液に相転移を研究するためのモデルシステムを確立します。

<table border="0" cellpadding="0" cellspacing="0" height="202" width="928">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:209px;">Material</td>
			<td style="width:208px;"></td>
			<td style="width:164px;"></td>
			<td style="width:352px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Zirconyl Chloride Octahydrate</td>
			<td>Fischer Scientific (Acros Organics)</td>
			<td>AC20837-5000</td>
			<td>98% +&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">o-Phosphoric Acid</td>
			<td>Fischer Scientific</td>
			<td>A242-1</td>
			<td>&#62;= 85 %</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Tetra Butyl Ammonium Hydroxide</td>
			<td>Acros Organics (Acros Organics)</td>
			<td>AC176610025</td>
			<td>40% wt. (1.5M)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Reaction Oven</td>
			<td>Fischer Scientific</td>
			<td>CL2 centrifuge</td>
			<td>Isotemperature Oven (Temperature Upto 350&#160;C)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Centrifuge&#160;</td>
			<td>Thermo Scientific</td>
			<td>Not Available&#160;</td>
			<td>Rotation Speed : 100 - 4000 rpm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microwave Reactor</td>
			<td>CEM Corporation</td>
			<td>Discover and Explorer SP</td>
			<td>Temp. Upto 300oC, Power upto 300W, Pressure upto 30bar</td>
		</tr>
	</tbody>
</table>

synthesis and exfoliation of discotic zirconium phosphates to obtain colloidal liquid crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

α-ZrPのナノディスクの図1A-Cに示すSEM画像は、それぞれ、水、還流、およびマイクロ波支援方法から得られます。これは、α-ZrPのナノディスク形状と合成条件と準備方法に応じて異なる厚さの六角形示すことが観察されました。我々のグループ6から以前に報告された研究では、結晶成長時間48時間以上のために、ディスクのエッジがシャープになることを示唆しています。通常、還流法収率α-ZrPのリン酸の濃度と反応時間6,7を含む同様の反応条件で水熱法で得られたよりもサイズが小さく、より少ない定期六角形でのナノディスク。 図1Dは、粒度分布のDSL結果を示しますそれに応じて三つの異なる合成し法でZrPの懸濁液を剥離します。 図2 </strong&gt;は、マイクロ波アシスト法によって作製α-ZrPの結晶のTEM画像を示します。これは、いくつかの結晶は、マイクロ波誘電加熱の10分後に形成された図2aに観察されました。 α-ZrPのいくつかの明確に定義された六角形の形状を見つけることができたが、得られた結晶のほとんどは、サイズ、形状も均一でもない規則的です。反応時間は60分、10分まで増加したとき、α-ZrPの結晶のシャープと正六角形は、最終製品のより良好な結晶性を示し、形成されました。本研究では、α-ZrPを合成するための必要な反応時間は大幅に時間未満に日からのマイクロ波誘電加熱の支援を受けて減少します。したがって、ナノ材料の製造のためのパラメータや設計の迅速な評価は、マイクロ波支援方法により達成することができます。 図3aは、複数の剥離工程を示す概略図であります単層への層の結晶。剥離サスペンションの物理的な外観は、真珠のような白（ 図3b）unexfoliatedサスペンションのが白濁している間です。 ZrPのナノディスクの分散安定性をチェックするために、分散液は、高い（4,000回転、2,500×gで）回転速度で1時間遠心分離しました。しかしながら、沈殿は、水中の分散液が原因たZrPナノディスク上の表面電荷の反発力に安定であることを証明している観察されませんでした。遠心分離後の剥離サンプルは時々部分的に剥離したZrPの口座に沈殿物の非常に少量を与えます。トップ部分は、同様に、剥離と考えられています。 図4は、交差した偏光子の対の間に観察されるように、左から右へのZrP単層の濃度の増加に伴ってサンプルを示します。濃度が増加するにつれて、ネマチック画分も同様に増加します。 図1. 24時間、200℃で12 H 3 PO 4（a）において水熱反応による塩化ジルコニル八水和物から調製した原始的なα-たZrPのSEM像。 （B）24時間、95℃で3 H 3 PO 4で還流方法。 （c）のマイクロ波アシスト法で15 MH 3 PO 4のための1時間200℃で、 （d）は 、熱水、逆流、およびマイクロ波支援の方法により調製剥離ZrPの懸濁液のためのナノディスクサイズ分析をDLS。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53511/53511fig1large.jpg" target="_blank">この図の拡大版をご覧になるにはこちらをクリックしてください。</a> <img alt="図2" src="/files/ftp_upload/53511/53511fig2.jpg" /> microwave-の図2. TEM像150℃でα-ZrPの結晶の成長を支援（a）は、10分、および（b）60分。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53511/53511fig2large.jpg" target="_blank">この図の拡大版をご覧になるにはこちらをクリックしてください。</a> <img alt="図3" src="/files/ftp_upload/53511/53511fig3.jpg" /> 図3（a）は、テトラを用いて層状リン酸ジルコニウムの剥離のプロセスの概略図（n）は、水酸化アンモニウムブチルTBA +イオン 、両側でのZrPディスクを覆います。ディスクの表面に酸素が負の電荷を有するように、システム内の全電荷はゼロです。 ZrPの時：TBAOHのモル比1：1、ほとんどすべてのTBA +イオンのZrPの表面上にあります。 TBA +イオンの量が増加しているように、TBA +イオンは、両側からのZrPディスクを囲みます。挿入図は、酸素（ZrPのの一部）とTBA +との間の静電相互作用を示していますナノディスクの表面にイオン。 （b）は Unexfoliated（左）と剥離（右）α-ZrPの懸濁液。中間層における（c）の剥離および還流法から調製されたα-ZrPのの分画のみ剥離したZrPは（マークされたように）収集される。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53511/53511fig3large.jpg" target="_blank">この図の拡大版をご覧になるにはこちらをクリックしてください。</a> <img alt="図4" src="/files/ftp_upload/53511/53511fig4.jpg" /> 図4.交差偏光子の間で観察され、左から右に濃度の増加に伴ってたZrPナノディスクの懸濁液。左から右へのナノディスクの体積分率：0.38パーセント、0.44パーセント、0.50パーセント、0.53パーセント、0.56パーセント、0.75％と1％、それぞれ0.63パーセント、。カラフルな部分は、ディスクのネマチック順序を示しています。重力により、ネマチックタクトイドは底に沈降します。この写真は、重力沈降物の3日後に撮影されていますネマチックタクトイドのエーション。

Watch this Scientific Journal Video about Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals at JoVE.com

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

コロイド液の結晶を得ることが合成とディスコティックリン酸ジルコニウムの剥離

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

synthesis-exfoliation-discotic-zirconium-phosphates-to-obtain

Nanyang Technological University

Research

JoVE Journal

Chemistry

8.4K ビュー.  Texas A&M University. A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers. 

ビデオ: Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization

The traditional strategy for the introduction of chemical functionalities is the use of solid-phase synthesis by appending suitably modified phosphoramidite precursors to the nascent chain. However, the conditions used during the synthesis and the restriction to rather short sequences hamper the applicability of this methodology. On the other hand, modified nucleoside triphosphates are activated building blocks that have been employed for the mild introduction of numerous functional groups into nucleic acids, a strategy that paves the way for the use of modified nucleic acids in a wide-ranging palette of practical applications such as functional tagging and generation of ribozymes and DNAzymes. One of the major challenges resides in the intricacy of the methodology leading to the isolation and characterization of these nucleoside analogues.
	
	In this video article, we present a detailed protocol for the synthesis of these modified analogues using phosphorous(III)-based reagents. In addition, the procedure for their biochemical characterization is divulged, with a special emphasis on primer extension reactions and TdT tailing polymerization. This detailed protocol will be of use for the crafting of modified dNTPs and their further use in chemical biology.

The protocol described herein aims to explain and abridge the numerous obstacles in the way of the intricate route leading to modified nucleoside triphosphates. Consequently, this protocol facilitates both the synthesis of these activated building-blocks and their availability for practical applications.

ヌクレオシド三リン酸 - 合成からの生化学的特徴付けへ

The  traditional strategy for the introduction of chemical functionalities is the  use of solid-phase synthesis by appending suitably modified ...

化学

Exfoliation of Egyptian Blue and Han Blue, Two Alkali Earth Copper Silicate-based Pigments

In a visualized example of the ancient past connecting with modern times, we describe the preparation and exfoliation of CaCuSi4O10 and BaCuSi4O10, the colored components of the historic Egyptian blue and Han blue pigments. The bulk forms of these materials are synthesized by both melt flux and solid-state routes, which provide some control over the crystallite size of the product. The melt flux process is time intensive, but it produces relatively large crystals at lower reaction temperatures. In comparison, the solid-state method is quicker yet requires higher reaction temperatures and yields smaller crystallites. Upon stirring in hot water, CaCuSi4O10 spontaneously exfoliates into monolayer nanosheets, which are characterized by TEM and PXRD. BaCuSi4O10 on the other hand requires ultrasonication in organic solvents to achieve exfoliation. Near infrared imaging illustrates that both the bulk and nanosheet forms of CaCuSi4O10 and BaCuSi4O10 are strong near infrared emitters. Aqueous CaCuSi4O10 and BaCuSi4O10 nanosheet dispersions are useful because they provide a new way to handle, characterize, and process these materials in colloidal form.

The preparation and exfoliation of CaCuSi4O10&#160;and BaCuSi4O10 are described. Upon stirring in hot water, CaCuSi4O10 spontaneously exfoliates into monolayers, whereas BaCuSi4O10&#160;requires ultrasonication in organic solvents. Near infrared (NIR) imaging illustrates the NIR emission properties of these materials, and aqueous dispersions of these nanomaterials are useful for solution processing.

エジプトの青と漢青、二アルカリ土類銅シリケート系顔料の剥離

In a visualized example of the ancient past connecting with modern times, we describe the preparation and exfoliation of CaCuSi4O10 and BaCuSi4O10, the ...

Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate using the Atomic Force Microscope (AFM), can provide key insights into physical interactions present within colloidal systems. Colloidal systems are widely existent in several applications including, pharmaceuticals, foods, paints, paper, soil and minerals, detergents, printing and much more.1-3 Furthermore, colloids can exist in many states such as emulsions, foams and suspensions. Using colloidal probe nanoscopy one can obtain key information on the adhesive properties, binding energies and even gain insight into the physical stability and coagulation kinetics of the colloids present within. Additionally, colloidal probe nanoscopy can be used with biological cells to aid in drug discovery and formulation development. In this paper we describe a method for conducting colloidal probe nanoscopy, discuss key factors that are important to consider during the measurement, and show that both quantitative and qualitative data that can be obtained from such measurements.

Colloidal probe nanoscopy can be used within a variety of fields to gain insight into the physical stability and coagulation kinetics of colloidal systems and aid in drug discovery and formulation sciences using biological systems. The method described within provides a quantitative and qualitative means to study such systems.

コロイドプローブナノスを使用して、粒子間相互作用の定量的および定性的調査

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate ...

From Constructs to Crystals &#8211; Towards Structure Determination of &#946;-barrel Outer Membrane Proteins

Membrane proteins serve important functions in cells such as nutrient transport, motility, signaling, survival and virulence, yet constitute only ~1% percent of known structures. There are two types of membrane proteins, &#945;-helical and &#946;-barrel. While &#945;-helical membrane proteins can be found in nearly all cellular membranes, &#946;-barrel membrane proteins can only be found in the outer membranes of mitochondria, chloroplasts, and Gram-negative bacteria. One common bottleneck in structural studies of membrane proteins in general is getting enough pure sample for analysis. In hopes of assisting those interested in solving the structure of their favorite &#946;-barrel outer membrane protein (OMP), general protocols are presented for the production of target &#946;-barrel OMPs at levels useful for structure determination by either X-ray crystallography and/or NMR spectroscopy. Here, we outline construct design for both native expression and for expression into inclusion bodies, purification using an affinity tag, and crystallization using detergent screening, bicelle, and lipidic cubic phase techniques. These protocols have been tested and found to work for most OMPs from Gram-negative bacteria; however, there are some targets, particularly for mitochondria and chloroplasts that may require other methods for expression and purification. As such, the methods here should be applicable for most projects that involve OMPs from Gram-negative bacteria, yet the expression levels and amount of purified sample will vary depending on the target OMP.

&#946;-barrel outer membrane proteins (OMPs) serve many functions within the outer membranes of Gram-negative bacteria, mitochondria, and chloroplasts. Here, we hope to alleviate a known bottleneck in structural studies by presenting protocols for the production of &#946;-barrel OMPs in sufficient quantities for structure determination by X-ray crystallography or NMR spectroscopy.

βバレル外膜タンパク質の構造決意を目指して - 構築物から結晶へ

Membrane proteins serve important functions in cells such as nutrient transport, motility, signaling, survival and virulence, yet constitute only ~1% ...

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addition reaction. Strain-to-failure and glass transition behavior were investigated as a function of crosslinking monomer, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). An example non-stoichiometric system of 15 mol% PETMP thiol groups and an excess of 15 mol% acrylate groups was used to demonstrate the robust nature of the material. The LCE formed an aligned and transparent monodomain when stretched, with a maximum failure strain over 600%. Stretched LCE samples were able to demonstrate both stress-driven thermal actuation when held under a constant bias stress or the shape-memory effect when stretched and unloaded. A permanently programmed monodomain was achieved via a second-stage photopolymerization reaction of the excess acrylate groups when the sample was in the stretched state. LCE samples were photo-cured and programmed at 100%, 200%, 300%, and 400% strain, with all samples demonstrating over 90% shape fixity when unloaded. The magnitude of total stress-free actuation increased from 35% to 115% with increased programming strain. Overall, the two-stage TAMAP methodology is presented as a powerful tool to prepare main-chain LCE systems and explore structure-property-performance relationships in these fascinating stimuli-sensitive materials.

A novel methodology is presented to synthesize and program main-chain liquid-crystalline elastomers using commercially available starting monomers. A wide range of thermomechanical properties was tailored by adjusting the amount of crosslinker, while the actuation performance was dependent on the amount of applied strain during programming.

二段チオールアクリレート反応を使用してプログラム可能な、主鎖液晶エラストマーの合成

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

超分子コロイドの合成とキャラクタリゼーション

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid crystals (ILCs). Taking advantages of the high specificity of XB for haloperfluorocarbons and the ability of anions to act as XB-acceptors, we obtained supramolecular complexes based on 1-alkyl-3-methylimidazolium iodides and iodoperfluorocarbons, overcoming the well-known immiscibility between hydrocarbons (HCs) and perfluorocarbons (PFCs). The high directionality of the XB combined with the fluorophobic effect, allowed us to obtain enantiotropic liquid crystals where a rigid, non-aromatic, XB supramolecular anion acts as mesogenic core.
X-ray structure analysis of the complex between 1-ethyl-3-methylimidazolium iodide and iodoperfluorooctane showed the presence of a layered structure, which is a manifestation of the well-known tendency to segregation of perfluoroalkyl chains. This is consistent with the observation of smectic mesophases. Moreover, all the reported complexes melt below 100 &#176;C, and most are mesomorphic even at room temperature, despite that the starting materials were non-mesomorphic in nature.
The supramolecular strategy reported here provides new design principles for mesogen design allowing a totally new class of functional materials.

A protocol for the synthesis of a new type of mesogens, based on the halogen-bonded supramolecular anion [CnF2n+1-I&#183;&#183;&#183;I&#183;&#183;&#183;I-CnF2n+1]&#8722;, is reported.

分子から素材まで: ハロゲン結合を介して新しいイオン液体結晶工学

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid ...

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.

A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.

ファセットとファセットの形状異方性のコロイド カドミウム カルコゲナイド系ナノ構造のリンク

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be ...

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational spectroscopy and time-resolved electron diffraction. Liquid crystal phase is an important state of matter that exists between the solid and liquid phases and it is common in natural systems as well as in organic electronics. Liquid crystals are orientationally ordered but loosely packed, and therefore, the internal conformations and alignments of the molecular components of LCs can be modified by external stimuli. Although advanced time-resolved diffraction techniques have revealed picosecond-scale molecular dynamics of single crystals and polycrystals, direct observations of packing structures and ultrafast dynamics of soft materials have been hampered by blurry diffraction patterns. Here, we report time-resolved IR vibrational spectroscopy and electron diffractometry to acquire ultrafast snapshots of a columnar LC material bearing a photoactive core moiety. Differential-detection analyses of the combination of time-resolved IR vibrational spectroscopy and electron diffraction are powerful tools for characterizing structures and photoinduced dynamics of soft materials.

Here, we present the protocols of differential-detection analyses of time-resolved infrared vibrational spectroscopy and electron diffraction which enable observations of the deformations of local structures around photoexcited molecules in a columnar liquid crystal, giving an atomic perspective on the relationship between the structure and the dynamics of this photoactive material.

光応答性液晶の構造ダイナミクスを観察する手法

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational ...

Exfoliation and Analysis of Large-area, Air-Sensitive Two-Dimensional Materials

We describe methods for producing and analyzing large, thin flakes of air-sensitive two-dimensional materials. Thin flakes of layered or van der Waals crystals are produced using mechanical exfoliation, in which layers are peeled off a bulk crystal using adhesive tape. This method produces high-quality flakes, but they are often small and can be hard to find, particularly for materials with relatively high cleavage energies such as black phosphorus. By heating the substrate and the tape, two-dimensional material adhesion to the substrate is promoted, and the flake yield can be increased by up to a factor of ten. After exfoliation, it is necessary to image or otherwise analyze these flakes but some two-dimensional materials are sensitive to oxygen or water and will degrade when exposed air. We have designed and tested a hermetic transfer cell to temporarily maintain the inert environment of a glovebox so that air-sensitive flakes can be imaged and analyzed with minimal degradation. The compact design of the transfer cell is such that optical analysis of sensitive materials can be performed outside of a glovebox without specialized equipment or modifications to existing equipment.

A method for exfoliating large thin flakes of air sensitive two-dimensional materials and safely transporting them for analysis outside of a glovebox is presented.

剥離と大面積解析空気敏感な二次元材料

We describe methods for producing and analyzing large, thin flakes of air-sensitive two-dimensional materials. Thin flakes of layered or van der Waals ...