この作品は、マリー·キュリー国際社会復帰グラントにより、ドイツ語·イスラエル財団によってサポートされていました。私たちは、AFM分析のために氏YAIR Razvagを認める。

1。ホモ芳香族ジペプチドの自己組織化<ol><li>その凍結乾燥形態（ 例えば、NH 2 -フェニルアラニン-フェニルアラニン-OH、をBoc-フェニルアラニン-フェニルアラニン-COOH）で所望のペプチドを秤量し、1,1,1,3,3,3 -ヘキサペプチドを溶解することにより原液を調製-2 -プロパノール7,17,46（NH 2-PheをPheで-OHおよびBoc-Pheを-フェニルアラニン-COOHための例えば 、100 mg / ml）を適当な濃度に（HFP）。 </li><li>ペプチドが完全に溶解し、溶液が（数分）明らかであると思われるまで、ベンチに渦と場所を使用して溶液を混合する。 </li><li>ペプチドの2μLを加えることで、適切な濃度（ナノチューブの形成のための三次蒸留水にNH 2-Pheを-Pheを-OH（TDW）の例えば 2ミリグラム/ mlに、適切な溶媒を用いて、ペプチドストック溶液を希釈98μLTDW、球状構造を形成するためのエタノール中のBoc-Pheを-Pheを-COOHの5 mg / ml）をへの原液。 </li><li> 24室温で溶液を準備しておく時間。 </li><li>任意の事前集計を避けるために、各実験のために新鮮なストック溶液を調製する。 </li></ol> 2。二つのホモ芳香族ジペプチドのCoassembly <ol><li> TDWと無水エタノールを等量混合し、50％エタノール溶液を調製する。 2溶液を混合し、ボルテックスを使用しています。 </li><li> NH 2-Pheを-Pheを-OHペプチドおよびBoc-Pheを-Pheを-OHペプチドの1ミリグラムの2 mgの重量を量る。 100ミリグラム/ mlの濃度にHFPの各ペプチドを溶解する。 </li><li>ボルテックスを用いてペプチドストック溶液を混合したペプチドが完全に溶解し、解決策が明確に見えるされるまで、ベンチの上に置きます。 </li><li>ペプチドを所望の比率にストック溶液をブレンド。この特定の実験では（それぞれ午前5時03分の最終比）のBoc-Pheを-Pheを-OHペプチドの6μLと、NH 2-Pheを-Pheを-OHペプチドの10μLをブレンド。原因HFP溶媒の揮発性が高いためには、（この原液を大量に用意することをお勧めしますLEAでST 10μL）。 </li><li>ブレンドされたペプチドストック溶液を混合する渦を使用してください。 </li><li>所望の最終濃度まで50％エタノールを用いてブレンドしたペプチドストック溶液を希釈する。この特定の実験では、それぞれのBoc-フェニルアラニン-フェニルアラニン-OHためのNH 2 -フェニルアラニン-フェニルアラニン-OHおよび3 mg / mlのために5 mg / mlの終濃度を得るために、ブレンドされたペプチドストック溶液8μlを加える50％エタノール溶液92μlをする。優しく溶液を混合するため、ピペットを使用しています。 </li><li> 24時間、この溶液を室温で保管してください。 </li><li>それは、溶媒の揮発性の高い性質のために、実験は、ペプチドの濃度の小さな変化に敏感であることに留意すべきである。したがって、新鮮なストック溶液を、各実験のために準備する必要があります。 </li></ol> 3。走査型電子顕微鏡（SEM）を用いて自己組織化構造のキャラクタリゼーション<ol><li>インキュベーションの24時間後、ガラス入り江に対するペプチド溶液10μl降下を適用RTでRスリップとドライ。 </li><li>コー​​ト90秒間スパッターコーターを用い、金の薄い層（数ナノメートル）を有するガラス上の試料。 </li><li>画像アセンブリを10から20 kVので作動するSEMを用いて。 </li></ol> 4。透過型電子顕微鏡（TEM）を用いて自己組織化構造のキャラクタリゼーション<ol><li> 200メッシュの銅グリッドカーボンで覆われ、高分子フィルム支持体によって安定化に対するペプチド溶液10μlの滴を置き。 </li><li> 1分後、ろ紙を用いて余分な水分を取り除く。 </li><li> TDWの2％酢酸ウラニル溶液を調製。 0.22μmのフィルターユニットを用いて溶液を濾過する。 </li><li>サンプル（ネガティブ染色）を染色するために、グリッド上の10μlの酢酸ウラニル溶液の液滴を配置します。 </li><li> 30秒後にろ紙を用いて余分な水分を取り除く。これは、ネガティブ染色画像のコントラストを向上するが、それはすべての場合には必須ではないことに留意すべきである。 </li><li>番目の画像上のサンプル120 kVので動作TEMによる電子グリッド。 </li></ol> 5。原子間力顕微鏡（AFM）によるアセンブリの三次元キャラ<ol><li>パラグラフ3.1に記載した手順を用いてAFM分析のためのサンプルを準備します。 </li><li> ACモードで動作し、AFM装置を用いてガラス上の試料を分析する。 3 N / mのバネ定数および75kHzでの共振周波数を有するシリコンカンチレバーを使用する。 </li><li>所望の構造を見つけるために、グリッドの大きな領域を走査することによって開始する。その後、特定の小さな領域に集中し、（スキャンサイズは、画像のために×2.5〜2.5μmであった。この原稿に含まれています）、それをスキャンします。 </li></ol> 6。 FT-IRによる二次構造のキャラクタリゼーション<ol><li> CaF 2の窓にペプチド溶液30μl降下を適用します。 </li><li>溶液を室温で乾燥させます。 </li><li> IRスペクトルにおける水の吸着1,650 cmと-1である。このピークは、ペプチド結合のアミドIバンドの中心にある。また、ペプチドおよびタンパク質47のα-ヘリックス構造の典型的なピークである。この問題を克服し、水のシグナルを回避するために、水素対重水素交換を行わなければならない。乾燥したペプチド試料に重水（D 2 O）のドロップを置きます。低下は完全にウィンドウ上のペプチドの沈殿物をカバーするのに十分な大きさでなければなりません。 </li><li>サンプルは真空下で乾燥させます。 </li><li>繰り返しは、最大の水素対重水素交換を確実にするために6.3と6.4倍を繰り返します。その分析まで真空下でサンプルを保存します。 </li><li>重水素化硫酸トリグリシン（DTGS）検出器を用いたFT-IRスペクトルを記録します。 FT-IRシステムは、試料の周囲の湿度を防ぐために、パージガス発生器を含む。短いペプチドのサンプルについては、それを4センチメートル-1の分解能で試料を2000 Xをスキャンすることをお勧めします。透過率の極小値は、そうすることによって決定することができるftware器に付属。 </li></ol>

著者は、彼らが競合する経済的利益を持っていないことを宣言します。

要約すると、本論文では、ペプチドベースのアセンブリはインビトロで形成することができる容易さを示しています。プロセスは、市販のペプチドおよび溶媒を伴い、それは試験管に極性溶媒を添加すると、周囲条件下で自発的に起こる。それは、他の有機溶媒にペプチドの溶解度が低いため、ペプチドの溶媒としてHFPを使用することが重要です。また、HFPの高い揮発性のために、各?...

自然形態は、生体分子の自己組織化のプロセスによって秩序構造と機能。この自発的なプロセスを支配する力を理解することは、in vitroで自己組織化を模倣する能力、その結果、材料科学10,11の分野で大きな進歩をもたらす可能性がある。ペプチドは、具体的には、それらは大きな構造的多様性、化学合成の容易さを提供するため、生体分子の構成要素として大きな期待を保持し、容易に生物学的および化学的実体で官能化することができる。ペプチドの自己集合のフィールドがGhadiri及びD-及びL-アミノ酸12を交互に環状ペプチドによるペプチドナノチューブの自己集合を示した彼の同僚によって開拓された。ペプチド集合体の設計に他の成功したアプローチは、線形bolaamphiphileペプチド5、両親媒性物質（AP）6、非共役自己相補イオン性ペプチド13、界面活性剤様ペプチド、 <suP&gt; 4,14、およびジブロックコポリ15。 より最近のアプローチは短い芳香族ペプチドの自己組織化を必要とする、ホモ芳香族ジペプチドと呼ばれる。これらのペプチドは、芳香族の性質（ 例えば、フェニルアラニン-フェニルアラニン、tert-ブチルジカーボネート（Boc）でのPhe-Pheを- ）7,8,16-21のみで2つのアミノ酸を含む。これらのホモ芳香族ペプチドにより形成される構造は、管状構造、球状、板状集合体および繊維6,8,15,21-32が含まれています。いくつかのケースでは繊維がヒドロゲル33-37が得フィブリルメッシュを生成します。これらのアセンブリは、バイオセンシング、薬物送達、分子エレクトロニクスなどのアプリケーションのために利用されている。38〜45 本論文では、ホモ芳香族ペプチドの自発的な自己組織化を開始するために必要とされる実験的な手順について説明します。また、coassemblyペプチドのプロセスを示す。このプロセスは、ペプチドの複数のタイプの自己集合を含むモノマー。 ジフェニルアラニンペプチド（NH 2-Pheを-Pheを-COOH）とそのBocはアナログを保護された（のBoc-Pheを-Pheを-OH）：私たちのデモでは、2つの市販のペプチドのcoassemblyが含まれています。溶剤7,17,46に応じて、球または繊維のいずれかにジフェニルアラニンペプチドの形の管状アセンブリおよびBoc-Pheを-Pheを-OHペプチド自己集合：超分子構造へのペプチドの自己集合のそれぞれ。我々は、一定の比率で二つのペプチドを配合し、電子顕微鏡、力顕微鏡法およびFT-IR分光法により得られたアセンブリを特徴とする。方法は、数百ナノメートル（〜300〜800ナノメートル）の直径を有する細長いアセンブリによって接続される数ミクロン（1-4ミクロン）の直径を有する球状の要素から構成されているペプチドベースの構造の形成を示した。球状​​構造がに螺ているように見えるようにアセンブリは、その形態にビーズの文字列に似ている細長いアセンブリ。そこで我々は、これらのアセンブリ「生体分子ネックレス」と呼ばれる。 「生体分子ネックレスは「薬物送達剤として、または電子的用途のための足場として、新しい生体材料となる恐れがあります。さらに、ペプチドの自己集合をもたらす手順は、ペプチド及び生体分子の他のクラスで利用されてもよい。これは、自己集合し、新しい秩序構造の形成に関与する力のよりよい理解につながる可能性がある。

<table border="1">
	<tbody>
		<tr>
			<td>Name of Material/ Equipment</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments/Description</td>
		</tr>
		<tr>
			<td>NH2-Phe-Phe-OH</td>
			<td>Bachem</td>
			<td>G-2925.0001</td>
			<td></td>
		</tr>
		<tr>
			<td>Boc-Phe-Phe-OH</td>
			<td>Bachem</td>
			<td>A-3205.0005</td>
			<td></td>
		</tr>
		<tr>
			<td>1,1,1,3,3,3-hexafluoro-2-propanol</td>
			<td>Sigma-Aldrich</td>
			<td>52512-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol absolute (Dehydrated) AR sterile</td>
			<td>Bio-Lab Ltd.</td>
			<td>52555</td>
			<td>Blending with TDW for the preparation of 50% solution</td>
		</tr>
		<tr>
			<td>Uranyl acetate</td>
			<td>Sigma-Aldrich</td>
			<td>73943</td>
			<td>For negative staining. It is possible to work without it.</td>
		</tr>
		<tr>
			<td>glass cover slip</td>
			<td>Marienfeld Laboratory Glassware</td>
			<td>110590</td>
			<td></td>
		</tr>
		<tr>
			<td>TEM grids</td>
			<td>Electron Microscopy Sciences</td>
			<td>FCF200-Cu-50</td>
			<td>Formvar/Carbon 200 Mesh, Cu</td>
		</tr>
		<tr>
			<td>Quantitive filter paper</td>
			<td>Whatman</td>
			<td>1001055</td>
			<td></td>
		</tr>
		<tr>
			<td>Deuterium Oxide (D2O)</td>
			<td>Sigma-Aldrich</td>
			<td>151882-100G</td>
			<td>99.9 atom % D</td>
		</tr>
		<tr>
			<td>CaF2 window</td>
			<td>PIKE Technologies</td>
			<td>160-1212</td>
			<td>25 mm x 2 mm window. For FT-IR measurments</td>
		</tr>
		<tr>
			<td>AFM tips</td>
			<td>NanoScience Instruments</td>
			<td>CFMR</td>
			<td>Aspire probes, CFMR-25 series</td>
		</tr>
		<tr>
			<td>Filter units</td>
			<td>Millipore</td>
			<td>SLGV033RS</td>
			<td>Millex-GV, 0.22 &#956;m, PVDF, 33 mm, gamma sterilized</td>
		</tr>
		<tr>
			<td>SEM</td>
			<td>FEI</td>
			<td></td>
			<td>Quanta 200 ESEM</td>
		</tr>
		<tr>
			<td>TEM</td>
			<td>FEI</td>
			<td></td>
			<td>Tecnai T12 G2 Spirit</td>
		</tr>
		<tr>
			<td>AFM</td>
			<td>JPK Instruments</td>
			<td></td>
			<td>A JPK NanoWizard3</td>
		</tr>
		<tr>
			<td>FT-IR</td>
			<td>Thermo Fisher Scientific</td>
			<td></td>
			<td>Nicolet 6700 advanced gold spectrometer</td>
		</tr>
		<tr>
			<td>FT-IR Purge</td>
			<td>Parker</td>
			<td></td>
			<td>BALSTON FT-IR Purge Gas Generator model 75-52</td>
		</tr>
		<tr>
			<td>OMNIC (Nicolet) software</td>
			<td>Thermo Nicolet Corporation</td>
			<td></td>
			<td>For FT-IR spectra analysis</td>
		</tr>
		<tr>
			<td>Vortex mixer</td>
			<td>Wisd Laboratory Equipment</td>
			<td></td>
			<td>ViseMix VM</td>
		</tr>
		<tr>
			<td>Weight</td>
			<td>Mettler Toledo</td>
			<td></td>
			<td>NewClassic MS</td>
		</tr>
		<tr>
			<td>Sputter coater</td>
			<td>Polaron</td>
			<td></td>
			<td>SC7640 Sputter Coater</td>
		</tr>
	</tbody>
</table>

formation of ordered biomolecular structures by the self-assembly of short peptides

自然界では、複雑な機能的構造は、温和な条件下での生体分子の自己集合により形成される。自己組織化を制御する力を理解し、in vitroで 、このプロセスを模倣することは、材料科学、ナノテクノロジーの分野で大きな進歩をもたらす。それらはかなりの多様性を提示するように、利用可能な生物学的なビルディングブロックの中では、ペプチドは、大規模での合成が簡単であり、いくつかの利点を有し、それらは容易に生物学的および化学的実体1,2で修飾することができる。このような環状ペプチド、両親媒性ペプチドおよびペプチド結合体溶液中の秩序構造に自己組織化するよう設計されたペプチドのいくつかのクラス。ホモ芳香族ジペプチドは、例えば、ナノチューブ、球体及びフィブリル3-8のような秩序構造を形成するのに必要な全ての分子の情報を含むショート自己組織化ペプチドのクラスである。これらのペプチドの多種多様な市販されている。 <pクラスは、= &quot;jove_content&quot;&gt;本稿ではホモ芳香族ペプチドの自己組織化による秩序構造の形成につながる手順を提示します。プロトコルは、市販の試薬および塩基性実験装置を必要とする。また、紙はペプチドベースの集合体の特性評価のために利用できる方法の一部について説明します。これらの方法は、電子および原子間力顕微鏡法及びフーリエ変換赤外分光法（FT-IR）を含む。また、原稿は、ペプチドのブレンド（coassembly）、この処理により様構造」糸に通したビーズ」の形成を示している。9ここに提示プロトコルが潜在的にできるペプチド又は生物学的なビルディング·ブロックの他のクラスに適合することができる新しいペプチドベースの構造の発見に、それらの集合体のよりよい制御につながる。

本稿では、ペプチドの自己組織化によるナノおよびマイクロメートルスケールでの秩序構造を形成するための方法を説明します。我々が存在し、この単純なプロセスを示し、2の単純な芳香族ペプチドのcoassembly（ 図1）を特徴づけるために。ペプチドの一つは、ナノメートル寸法7を備えた中空の管状構造に水溶液中で自己集合することができ、NH 2-Pheを-Pheを-OH（?...

Watch this Scientific Journal Video about Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides at JoVE.com

Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides

本論文では、自己組織化の自発的プロセスによる高度に秩序ペプチドベースの構造の形成を説明しています。この方法は、市販のペプチドおよび共通実験装置を利用しています。この技術は、ペプチドの多種多様に適用することができる、新たなペプチドベースアセンブリの発見につながることができる。

短いペプチドの自己組織化によって順序付け生体分子構造の形成

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control ...

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12.8K ビュー.  The Hebrew University of Jerusalem. 本論文では、自己組織化の自発的プロセスによる高度に秩序ペプチドベースの構造の形成を説明しています。この方法は、市販のペプチドおよび共通実験装置を利用しています。この技術は、ペプチドの多種多様に適用することができる、新たなペプチドベースアセンブリの発見につながることができる。 

ビデオ: Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides

Origami Inspired Self-assembly of Patterned and Reconfigurable Particles

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two dimensional (2D) structures. These technologies are mature, offer high precision and many of them can be implemented in a high-throughput manner. We leverage the advantages of planar lithography and combine them with self-folding methods1-20 wherein physical forces derived from surface tension or residual stress, are used to curve or fold planar structures into three dimensional (3D) structures. In doing so, we make it possible to mass produce precisely patterned static and reconfigurable particles that are challenging to synthesize.
In this paper, we detail visualized experimental protocols to create patterned particles, notably, (a) permanently bonded, hollow, polyhedra that self-assemble and self-seal due to the minimization of surface energy of liquefied hinges21-23 and (b) grippers that self-fold due to residual stress powered hinges24,25. The specific protocol described can be used to create particles with overall sizes ranging from the micrometer to the centimeter length scales. Further, arbitrary patterns can be defined on the surfaces of the particles of importance in colloidal science, electronics, optics and medicine. More generally, the concept of self-assembling mechanically rigid particles with self-sealing hinges is applicable, with some process modifications, to the creation of particles at even smaller, 100 nm length scales22, 26 and with a range of materials including metals21, semiconductors9 and polymers27. With respect to residual stress powered actuation of reconfigurable grasping devices, our specific protocol utilizes chromium hinges of relevance to devices with sizes ranging from 100 &mu;m to 2.5 mm. However, more generally, the concept of such tether-free residual stress powered actuation can be used with alternate high-stress materials such as heteroepitaxially deposited semiconductor films5,7 to possibly create even smaller nanoscale grasping devices.

We describe experimental details of the synthesis of patterned and reconfigurable particles from two dimensional (2D) precursors. This methodology can be used to create particles in a variety of shapes including polyhedra and grasping devices at length scales ranging from the micro to centimeter scale.

折り紙インスパイアパターン化され、再構成可能な粒子の自己組織化

There are numerous techniques such as photolithography, electron-beam lithography and soft-lithography that can be used to precisely pattern two ...

化学

Rapid Colorimetric Assays to Qualitatively Distinguish RNA and DNA in Biomolecular Samples

Biochemical experimentation generally requires accurate knowledge, at an early stage, of the nucleic acid, protein, and other biomolecular components in potentially heterogeneous specimens. Nucleic acids can be detected via several established approaches, including analytical methods that are spectrophotometric (e.g., A260), fluorometric (e.g., binding of fluorescent dyes), or colorimetric (nucleoside-specific chromogenic chemical reactions).1 Though it cannot readily distinguish RNA from DNA, the A260/A280 ratio is commonly employed, as it offers a simple and rapid2 assessment of the relative content of nucleic acid, which absorbs predominantly near 260 nm and protein, which absorbs primarily near 280 nm. Ratios &lt; 0.8 are taken as indicative of 'pure' protein specimens, while pure nucleic acid (NA) is characterized by ratios &gt; 1.53.
However, there are scenarios in which the protein/NA content cannot be as clearly or reliably inferred from simple uv-vis spectrophotometric measurements. For instance, (i) samples may contain one or more proteins which are relatively devoid of the aromatic amino acids responsible for absorption at &asymp;280 nm (Trp, Tyr, Phe), as is the case with some small RNA-binding proteins, and (ii) samples can exhibit intermediate A260/A280 ratios (~0.8 &lt; ~1.5), where the protein/NA content is far less clear and may even reflect some high-affinity association between the protein and NA components. For such scenarios, we describe herein a suite of colorimetric assays to rapidly distinguish RNA, DNA, and reducing sugars in a potentially mixed sample of biomolecules. The methods rely on the differential sensitivity of pentoses and other carbohydrates to Benedict's, Bial's (orcinol), and Dische's (diphenylamine) reagents; the streamlined protocols can be completed in a matter of minutes, without any additional steps of having to isolate the components. The assays can be performed in parallel to differentiate between RNA and DNA, as well as indicate the presence of free reducing sugars such as glucose, fructose, and ribose (Figure 1).

A suite of colorimetric assays is described for rapidly distinguishing protein, RNA, DNA, and reducing sugars in potentially heterogeneous biomolecular samples.

定性的には生体試料中のRNAおよびDNAを区別するために迅速比色アッセイ

Biochemical experimentation generally requires accurate knowledge, at an early stage, of the nucleic acid, protein, and other biomolecular components in ...

Microwave-assisted Functionalization of Poly(ethylene glycol) and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large variety of PEG molecular weights and configurations (arm number, arm length, and branching pattern) affords researchers tight control over resulting hydrogel structures and properties, including Young&#8217;s modulus and mesh size. This video will illustrate a rapid, efficient, solvent-free, microwave-assisted method to methacrylate PEG precursors into poly(ethylene glycol) dimethacrylate (PEGDM). This synthetic method provides much-needed starting materials for applications in drug delivery and regenerative medicine. The demonstrated method is superior to traditional methacrylation methods as it is significantly faster and simpler, as well as more economical and environmentally friendly, using smaller amounts of reagents and solvents. We will also demonstrate an adaptation of this technique for on-resin methacrylamide functionalization of peptides. This on-resin method allows the N-terminus of peptides to be functionalized with methacrylamide groups prior to deprotection and cleavage from resin. This allows for selective addition of methacrylamide groups to the N-termini of the peptides while amino acids with reactive side groups (e.g.&#160;primary amine of lysine, primary alcohol of serine, secondary alcohols of threonine, and phenol of tyrosine) remain protected, preventing functionalization at multiple sites. This article will detail common analytical methods (proton Nuclear Magnetic Resonance spectroscopy (;H-NMR) and Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-ToF)) to assess the efficiency of the functionalizations. Common pitfalls and suggested troubleshooting methods will be addressed, as will modifications of the technique which can be used to further tune macromer functionality and resulting hydrogel physical and chemical properties. Use of synthesized products for the formation of hydrogels for drug delivery and cell-material interaction studies will be demonstrated, with particular attention paid to modifying hydrogel composition to affect mesh size, controlling hydrogel stiffness and drug release.

Microwave-assisted Functionalization of Polyethylene glycol and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

This video will illustrate a rapid, efficient method to methacrylate poly(ethylene glycol), enabling chain polymerizations and hydrogel synthesis. It will demonstrate how to similarly introduce methacrylamide functionalities into peptides, detail common analytical methods to assess functionalization efficiency, provide suggestions for troubleshooting and advanced modifications, and demonstrate typical hydrogel characterization techniques.

マイクロ波支援ポリの機能化（エチレングリコール）と連鎖重合で使用するためには樹脂ペプチドおよびヒドロゲル形成

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large ...

Self-assembly of Complex Two-dimensional Shapes from Single-stranded DNA Tiles

Current methods in DNA nano-architecture have successfully engineered a variety of 2D and 3D structures using principles of self-assembly. In this article, we describe detailed protocols on how to fabricate sophisticated 2D shapes through the self-assembly of uniquely addressable single-stranded DNA tiles which act as molecular pixels on a molecular canvas. Each single-stranded tile (SST) is a 42-nucleotide DNA strand composed of four concatenated modular domains which bind to four neighbors during self-assembly. The molecular canvas is a rectangle structure self-assembled from SSTs. A prescribed complex 2D shape is formed by selecting the constituent molecular pixels (SSTs) from a 310-pixel molecular canvas and then subjecting the corresponding strands to one-pot annealing. Due to the modular nature of the SST approach we demonstrate the scalability, versatility and robustness of this method. Compared with alternative methods, the SST method enables a wider selection of information polymers and sequences through the use of de novo designed and synthesized short DNA strands.

DNA tiling is an effective approach to make programmable nanostructures. We describe the protocols to construct complex two-dimensional shapes by the self-assembly of single-stranded DNA tiles.

一本鎖DNAタイルから複雑な2次元形状の自己集合

Current methods in DNA nano-architecture have successfully engineered a variety of 2D and 3D structures using principles of self-assembly. In this ...

Highly Stable, Functional Hairy Nanoparticles and Biopolymers from Wood Fibers: Towards Sustainable Nanotechnology

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While metal-based nanoparticles are associated with synthetic and environmental hassles, cellulose introduces a green, sustainable alternative for nanoparticle synthesis. Here, we present the chemical synthesis and separation procedures to produce new classes of hairy nanoparticles (bearing both amorphous and crystalline regions) and biopolymers based on wood fibers. Through periodate oxidation of soft wood pulp, the glucose ring of cellulose is opened at the C2-C3 bond to form 2,3-dialdehyde groups. Further heating of the partially oxidized fibers (e.g., T = 80 &#176;C) results in three products, namely fibrous oxidized cellulose, sterically stabilized nanocrystalline cellulose (SNCC), and dissolved dialdehyde modified cellulose (DAMC), which are well separated by intermittent centrifugation and co-solvent addition. The partially oxidized fibers (without heating) were used as a highly reactive intermediate to react with chlorite for converting almost all aldehyde to carboxyl groups. Co-solvent precipitation and centrifugation resulted in electrosterically stabilized nanocrystalline cellulose (ENCC) and dicarboxylated cellulose (DCC). The aldehyde content of SNCC and consequently surface charge of ENCC (carboxyl content) were precisely controlled by controlling the periodate oxidation reaction time, resulting in highly stable nanoparticles bearing more than 7 mmol functional groups per gram of nanoparticles (e.g., as compared to conventional NCC bearing &#60;&#60; 1 mmol functional group/g). Atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) attested to the rod-like morphology. Conductometric titration, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), electrokinetic-sonic-amplitude (ESA) and acoustic attenuation spectroscopy shed light on the superior properties of these nanomaterials.

Synthesis schemes to prepare highly stable wood fiber-based hairy nanoparticles and functional cellulose-based biopolymers have been detailed.

高安定、機能毛深いナノ粒子と木材繊維からバイオポリマー：持続可能なナノテクノロジーに向けて

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While ...

Insights into the Interactions of Amino Acids and Peptides with Inorganic Materials Using Single-Molecule Force Spectroscopy

The interactions between proteins or peptides and inorganic materials lead to several interesting processes. For example, combining proteins with minerals leads to the formation of composite materials with unique properties. In addition, the undesirable process of biofouling is initiated by the adsorption of biomolecules, mainly proteins, on surfaces. This organic layer is an adhesion layer for bacteria and allows them to interact with the surface. Understanding the fundamental forces that govern the interactions at the organic-inorganic interface is therefore important for many areas of research and could lead to the design of new materials for optical, mechanical and biomedical applications. This paper demonstrates a single-molecule force spectroscopy technique that utilizes an AFM to measure the adhesion force between either peptides or amino acids and well-defined inorganic surfaces. This technique involves a protocol for attaching the biomolecule to the AFM tip through a covalent flexible linker and single-molecule force spectroscopy measurements by atomic force microscope. In addition, an analysis of these measurements is included.

Here we present a protocol to measure the force of interactions between a well-defined inorganic surface and either peptides or amino acids by single-molecule force spectroscopy measurements using an atomic force microscope (AFM). The information obtained from the measurement is important to better understand the peptide-inorganic material interphase.

単一分子力分光法を用いて無機材料とアミノ酸とペプチドの相互作用への洞察

The interactions between proteins or peptides and inorganic materials lead to several interesting processes. For example, combining proteins with minerals ...

Grafting Multiwalled Carbon Nanotubes with Polystyrene to Enable Self-Assembly and Anisotropic Patchiness

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a free-radical polymerization strategy to enable the modulation of the nanotube surface properties and produce supramolecular self-assembly of the nanostructures. First, a selective hydroxylation of the pristine nanotubes through a biphasic catalytically mediated oxidation reaction creates superficially distributed reactive sites at the sidewalls. The latter reactive sites are subsequently modified with methacrylic moieties using a silylated methacrylic precursor to create polymerizable sites. Those polymerizable groups can address further polymerization of styrene to produce a hybrid nanomaterial containing PS chains grafted to the nanotube sidewalls. The polymer-graft content, amount of silylated methacrylic moieties introduced and hydroxylation modification of the nanotubes are identified and quantified by Thermogravimetric Analysis (TGA). The presence of reactive functional groups hydroxyl and silylated methacrylate are confirmed by Fourier Transform Infrared Spectroscopy (FT-IR). Polystyrene-grafted carbon nanotube solutions in tetrahydrofuran (THF) provide wall-to-wall collinearly self-assembled nanotubes when cast samples are analyzed by transmission electron microscopy (TEM). Those self-assemblies are not obtained when suitable blanks are similarly cast from analogous solutions containing non-grafted counterparts. Therefore, this method enables the modification of the nanotube anisotropic patchiness at the sidewalls which results into spontaneous auto-organization at the nanoscale.

A procedure for the synthesis of polystyrene-grafted multiwalled carbon nanotubes using successive chemical modification steps to selectively introduce the polymer chains to the sidewalls and their self-assembly via anisotropic patchiness is presented.

ポリスチレン自己組織を有効にして異方的不均一性と多層カーボンナノ チューブを移植

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a ...

Liquid-cell Transmission Electron Microscopy for Tracking Self-assembly of Nanoparticles

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully understood. We have traced the trajectories of individual nanoparticles using liquid-cell transmission electron microscopy (TEM) to investigate the mechanism of the assembly process. Herein, we present the protocols used for liquid-cell TEM studies of the self-assembly mechanism. First, we introduce the detailed synthetic protocols used to produce uniformly sized platinum and lead selenide nanoparticles. Next, we present the microfabrication processes used to produce liquid cells with silicon nitride or silicon windows and then describe the loading and imaging procedures of the liquid-cell TEM technique. Several notes are included to provide helpful tips for the entire process, including how to manage the fragile cell windows. The individual motions of nanoparticles tracked by liquid-cell TEM revealed that changes in the solvent boundaries caused by evaporation affected the self-assembly process of nanoparticles. The solvent boundaries drove nanoparticles to primarily form amorphous aggregates, followed by flattening of the aggregates to produce a 2-dimensional (2D) self-assembled structure. These behaviors are also observed for different nanoparticle types and different liquid-cell compositions.

Here we introduce experimental protocols for the real-time observation of a self-assembly process using liquid-cell transmission electron microscopy.

ナノ粒子の自己集合の追跡のため液晶セルの透過電子顕微鏡観察

Drying a nanoparticle dispersion is a versatile way to create self-assembled structures of nanoparticles, but the mechanism of this process is not fully ...

Fabrication of Spherical and Worm-shaped Micellar Nanocrystals by Combining Electrospray, Self-assembly, and Solvent-based Structure Control

Micellar nanocrystals (micelles with encapsulated nanocrystals) have become an emerging major class of nanobiomaterials. We describe a method of fabricating micellar nanocrystals based on combining top-down electrospray, bottom-up self-assembly, and solvent-based structure control. This method involves first using electrospray to generate uniform ultrafine liquid droplets, each of which functions as a micro-reactor in which self-assembly reaction occurs forming micellar nanocrystals, with the structures (micelle shape and nanocrystal encapsulation) controlled by the organic solvent used. This method is largely continuous and produces high quality micellar nanocrystal products with an inexpensive structure control approach. By using a water-miscible organic solvent tetrahydrofuran (THF), worm-shaped micellar nanocrystals can be produced due to solvent-induced/facilitated micelle fusion. Compared with the common spherical micellar nanocrystals, worm-shaped micellar nanocrystals can offer minimized non-specific cellular uptake, thus enhancing biological targeting. By co-encapsulating multiple nanocrystals into each micelle, multifunctional or synergistic effects can be achieved. Current limitations of this fabrication method, which will be part of the future work, primarily include imperfect encapsulation in the micellar nanocrystal product and the incompletely continuous nature of the process.

The present work describes a method to fabricate micellar nanocrystals, an emerging major class of nanobiomaterials. This method combines top-down electrospray, bottom-up self-assembly, and solvent-based structure control. The fabrication method is largely continuous, can produce high quality products, and possesses an inexpensive means of structure control.

組み立て式、エレクトロ スプレーを組み合わせることによって球形とワーム状ミセル ナノ結晶と溶剤ベースの構造制御の作製

Micellar nanocrystals (micelles with encapsulated nanocrystals) have become an emerging major class of nanobiomaterials. We describe a method of ...

Luminophore Formation in Various Conformations of Bovine Serum Albumin by Binding of Gold(III)

The purpose of the presented protocols is to study the process of Au(III) binding to BSA, yielding conformation change-induced red fluorescence (&#955;em = 640 nm) of BSA-Au(III) complexes. The method adjusts the pH to show that the emergence of the red fluorescence is correlated with the pH-induced equilibrium transitions of the BSA conformations. Red fluorescent BSA-Au(III) complexes can only be formed with an adjustment of pH at or above 9.7, which corresponds to the &#34;A-form&#34; conformation of BSA. The protocol to adjust the BSA to Au molar ratio and to monitor the time-course of the process of Au(III) binding is described. The minimum number of Au(III) per BSA, to produce the red fluorescence, is less than seven. We describe the protocol in steps to illustrate the presence of multiple Au(III) binding sites in BSA. First, by adding copper (Cu(II)) or nickel (Ni(II)) cations followed by Au(III), this method reveals a binding site for Au(III) that is not the red fluorophore. Second, by modifying BSA by thiol capping agents, another nonfluorophore-forming Au(III) binding site is revealed. Third, changing the BSA conformation by cleaving and capping of the disulfide bonds, the possible Au(III) binding site(s) are illustrated. The protocol described, to control the BSA conformations and Au(III) binding, can be generally applied to study the interactions of other proteins and metal cations.

Luminophore Formation in Various Conformations of Bovine Serum Albumin by Binding of GoldIII

The protocols for studying the binding of gold cations (Au(III)) to various conformations of bovine serum albumin (BSA) as well as for characterizing the conformational dependent unique BSA-Au fluorescence are presented.

Luminophore 金の結合によるウシ血清アルブミンの様々 な立体構造の形成

The purpose of the presented protocols is to study the process of Au(III) binding to BSA, yielding conformation change-induced red fluorescence (&#955;em ...