HL671795、HL048743、およびHL108630：この作品は、NIHの助成金によってサポートされていました。

SDF-1αグリカンナノ粒子の作製 インビボ送達の目的のために、調製に使用される全ての容器、ピペット、とヒントを滅菌する。 <ol><li>超純水で、次のストック溶液の準備：1％硫酸デキストランを。 1 MのNaOH（滅菌PES膜で濾過したもの）; 0.2％の氷酢酸中の0.1％キトサン（連続して、0.8〜0.22μmのフィルターを通して濾過し、その後NaOHでpHを5.5に調整する）; 0.1 MのZnSO 4。 15％マンニトール。 0.92 mg / mlのSDF-1α（80℃でアリコートで保存し、4℃で維持を一旦解凍C）。 </li><li> 0.22μmのフィルター膜を通すストック溶液を滅菌する。カブトガニ変形細胞溶解物（LAL）ゲルクロットアッセイと調製した溶液中のエンドトキシンレベルを評価。レベルは&lt;0.06 EU / mlであることを確認します。 </li><li>磁気撹拌棒を含む1.5 mlのガラスバイアルに0.18ミリリットルの超純水を加える。 800rpmで撹拌速度を設定します。 0.1ミリリットルの1％を追加します。硫酸デキストラン、2分間撹拌した。 0.08 mgのSDF-1α（0.92 mg / mlのSDF-1α溶液を0.087ミリリットル）を追加し、20分間攪拌。 </li><li> 0.33ミリリットルの0.1％キトサンを滴下して添加し、5分間撹拌した。最大に変更し、撹拌速度をと（1分以上）0.1ミリリットルの注射器でゆっくりと0.1ミリリットルの0.1MのZnSO 4を追加します。 </li><li>を800rpmに攪拌速度を戻し、30分間撹拌した。 0.4ミリリットルの15％のマンニトールを加え、5分間攪拌する。 1.5mlマイクロチューブに反応混合物を転送します。 10分間4℃で16000×gで遠心し。 注意：マンニトールの存在は、遠心分離後の粒子の再懸濁を容易にします。ペレットの小型化に応じて、マンニトールの濃度は、0％から5％に変化させることができる。各遠心分離後の粒子の完全な再懸濁は、最終懸濁液中の凝集を回避することが重要です。 </li><li>上清を吸引し、ゆっくりと液体の最後の一滴を削除するには、ピペットを使用しています。 0.2ミリリットルの5％マンニトールを追加します。 0.5ミリリットルとのペレットを中断し、29 G旧姓DLE注射器。 1ミリリットルの5％マンニトールを追加します。 15分間16000×gで遠心分離する。 </li><li>手順を繰り返し1.6。 </li><li>上清を吸引除去する。 0.2ミリリットルの5％マンニトールでペレットを再懸濁。 4℃で粒子懸濁液に保管してください。 注：粒子懸濁液は、-80℃で凍結または凍結乾燥することができる。懸濁液中を含む5％のマンニトールを凍結融解した後、凍結乾燥及び再水和の後、粒子の凝集を防止することが必須である。マンニトールは、保存後の懸濁液の遠心分離により除去することができる。 </li></ol>粒子径およびゼータ電位の2.測定粒径およびゼータ電位を素材リストに示され、粒子分析器を用いて、それぞれ、動的光散乱法、電気泳動光散乱によって分析される。 <ol><li>積算回数：以下の粒子サイズ測定のためのパラメータを設定する70。リピート回数：4;温度：25°C。希釈液：水;強度調整：オート。 </li><li>水（10倍希釈）とSDF-1α-DS-CSサンプルを希釈する。そのようなエッペンドルフキュベットのような使い捨てのUVキュベットに100μlの試料をロードします。セルホルダーにキュベットを挿入します。 「最適」（〜万CPS）に到達するために強度調整を待ちます。データ収集を開始します。 </li><li>測定が完了した後、直径（nm）であり、多分散性指数のキュムラントの結果を記録する。 4繰り返し測定値のそれぞれから得られた結果を平均し、標準偏差を計算する。 </li><li>負荷ゼータ電位測定用のフローセルに10倍希釈された粒子試料を500μl。蓄積時間：以下の測定のためのパラメータを設定し10と、リピート回数：5;温度：25°C。希釈液：水;強度調整：オート。ゼータ電位（MV）の結果を記録します。平均の結果は、5を繰り返し測定値のそれぞれから得られ、標準deviatioを計算N。 </li></ol>粒子におけるSDF-1αの3定量<ol><li> 1.3倍Laemmliサンプルバッファーで0.01、0.02、0.03、0.04、および0.05 mg / mlの濃度に自由形式のSDF-1αを希釈する。 40μlの1.3倍Laemmliサンプルバッファーで6μlのSDF-1α-DS-CSサンプルを希釈する。 （0.05ミリグラム/ブロモフェノールブルーミリリットル、8％2-メルカプトエタノール0.25 Mトリス塩酸、pHが7.5、8％SDS、40％グリセロールを含む4倍レムリストック緩衝を準備します。小さなアリコートに原液を分割し、-20℃で保つ単回使用のためにCを°。） </li><li> 10分間100℃で試料を加熱する。渦完全に粒子を解離するために、10分の加熱時間の間、二倍のサンプル（最大速度で10秒間ずつ）。 2分間RTにサンプルをクールダウン。凝縮水をダウンさせるために30秒〜1分間万×gで遠心し。もう一度よく混ぜるする渦。 注：この時点では、試料液が目に見える沈殿物が存在すると明確にする必要があります。 </li><li>負荷10＆＃181; Lサンプル/ウェルに4〜20％SDSゲル。 20分間200Vで電気泳動を実行します。クマシーブルータンパク質染色でゲルを染色。 </li><li>分子イメージャとトメ解析ソフトウェアを使用して、SDF-1αのタンパク質バンドの密度を調べます。無料のSDF-1α基準に作成した標準曲線に対して粒子中のSDF-1αの量を計算します。 </li></ol> インビトロ放出アッセイ4. <ol><li> 1でカルシウムとマグネシウム（D-PBS）なしのダルベッコのリン酸緩衝生理食塩水でSDF-1αグリカン粒子を混ぜる：1の比（v / v）である。 </li><li> 1.5ミリリットルチューブ内の0.05ミリリットルのアリコートに粒子懸濁液を分割します。チューブの底にサンプルをロードします。気泡を導入するか、液体の表面を乱さない。パラフィルムを有する管の上部をシール。 注：その際、液体がチューブミキサーに後続の上から下への回転時に底に残る。 </li><li> 37でチューブを回転させて＃176; C回転マイクロ​​チューブミキサーで。指定された時間にチューブからアリコートを取り出し、すぐに4℃で10分間16000×gでサンプルを遠心する。 </li><li>上清およびペレットを分離し、0.05ミリリットルD-PBSでペレットを再構成。 -20℃でサンプルを保管してください。全てのサンプルが収集された後、上述したように、SDSゲル上で上清およびペレットを調べる。 </li></ol> 5.移動アッセイこのアッセイは、SDF-1αの走化性活性を測定します。細胞表面上のその受容体（CXCR4）とSDF-1αの相互作用は、SDF-1αの勾配に向かって細胞の遊走を引き起こす。このアッセイでは、細胞が低くウェルに及びSDF-1α溶液（下井戸から半透膜で区切られた）上部のウェルにロードされます。 <ol><li> SDF-1αを希釈（遊離または粒子に結合した形）3-foのマイグレーションバッファー（0.5％ウシ血清アルブミンを含むRPMI-1640培地）と100、33、11、3.7、1.2、0.41、0.14、および0.05 ng / mlの最終濃度にLDの連続希釈。 </li><li> 24ウェルプレート中のウェルに希釈したSDF-1αソリューションや移行バッファーのみ（陰性対照）の0.6ミリリットルを追加します。ウェル（入力セル制御）に0.57ミリリットルの移行バッファを追加します。 30分間37℃でインキュベートする。そのような低いウェルの上にトランスウェル（孔径5μmの、直径6.5ミリメートル）のような透過性細胞培養インサートを置きます。トランスウェルインサートにロード0.1ミリリットルジャーカット細胞（5×10 5）。よく直接入力セルコントロールに0.03ミリリットルの細胞をロードします。 5％CO 2インキュベーター中で2時間、37℃でプレートをインキュベート。 </li><li>トランスウェルインサートを取り外します。 4ミリリットルポリスチレンチューブに下のウェルに移動した細胞を転送します。フローサイトメーターで移動した細胞を数える。 </li><li> negat内の数字を引いた後の入力セル数（ウェル100/30入力xセル制御中の細胞数）の割合としての移行を計算するコントロール（のみ泳動緩衝液を含むウェルに遊走した細胞）をアイブ。 </li></ol>

<ol>
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The authors declare that they have no competing financial interests.

上記のように、DS-CSナノ粒子はポリアニオン（DS）及びポリカチオン（CS）分子間の電荷中和により形成される。電荷相互作用は、分子衝突の間に容易に起こるので、混合中のポリマー溶液と撹拌速度の濃度は、得られた粒子のサイズのために重要である。一般的な傾向は、よりDSとCSのソリューション15と、より小さい粒子より高い撹拌速度結果を希釈することである。 <p class="jove_...

デキストラン硫酸（DS）及びキトサン（CS）は、（CSを脱アセチル化）（DS）の複数の置換、負に帯電した硫酸基を有する多糖類である、又は正に帯電したアミン基を。水溶液中で混合する場合、2つの多糖類は、静電相互作用を介して高分子電解質複合体を形成する。得られた複合体は、水溶液（沈殿物）からの相分離、または水分散性（コロイド）である小さい粒子となり、大きな凝集体を形成することができる。これらの成果に貢献する具体的な条件は、広く研究されており、最近の総説1にまとめ、詳細に説明してきた。これらの条件の中で、水分散性粒子を製造するための2つの基本的な要件は反対に荷電したポリマーは、1）著しく異なるモル質量を持っている必要がある。 2）非化学量論比で混合する。これらの条件は、電荷によって発生した電荷中立複合化ポリマーセグメントを許可します中和は、分離し、粒子のコアを形成し、過剰なポリマーは、外殻1を形成するためである。このプロトコールに記載されたグリカン粒子は、肺送達のために意図され、負に帯電し、ナノメートル寸法の正味のように設計されている。負の表面電荷は、粒子2,3の細胞取り込みの可能性を低減する。ナノメートル寸法の粒子は、遠位気道の通過を容易にする。この目標を達成するために、この調製に用いられるDSの量は、CSの過剰である（重量比3：1）。及び高分子量DS（重量平均MW50万）および低分子量CS（MW範囲50から190 kDaの、75％〜85％脱アセチル化）が使用されている。 SDF-1αは、その走化性活性を通じてホーミング機能を発揮する幹細胞のホーミング因子である。 SDF-1αは、ホーミングおよび骨髄中の造血幹細胞の維持に重要な役割を果たし、progeの動員傷害の修復4,5のための末梢組織へnitor細胞。 SDF-1αタンパク質は、プロテアーゼ（CD26 / DPPIV）不活性化から保護され、ヘパリン/ヘパラン硫酸、フォームダイマーに結合し、細胞表面受容体を介して標的細胞と相互作用することができ、そのタンパク質配列において、ヘパリン結合部位を有する6-8。 DSはヘパリン/ヘパラン硫酸と同様の構造特性を持つ。このように、DSにSDF-1αの結合は、その天然高分子リガンドのものと同様であろう。 以下のプロトコールでは、SDF-1α-DS-CSナノ粒子の調製を記載する。手順は以前に9を検討されてきた製剤のいずれかを表す。プロトコルは、もともとVEGF-DS-CSナノ粒子10の調査から適合される。小規模調製物は、容易に同一のストック溶液と製造条件をスケールアップすることができ、記載されている。調製の後、粒子がbを特徴とするyは、それらのサイズ、ゼータ電位、SDF-1α取り込みの程度を、in vitroでの放出時間、及び組み込まれたSDF-1αの活性を調べる。

<table border="0" cellpadding="0" cellspacing="0" width="489">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:255px;">Name</td>
			<td style="width:136px;">Company</td>
			<td style="width:99px;">Catalog number</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Dextran sulfate</td>
			<td>Fisher</td>
			<td>BP1585-100</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Chitosan, low molecular weight&#160;</td>
			<td>Sigma</td>
			<td>448869</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Zinc sulfate heptahydrate</td>
			<td>Sigma</td>
			<td>204986</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">D-Mannitol</td>
			<td>Sigma</td>
			<td>M9546</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">UltraPure water&#160;</td>
			<td>Invitrogen&#160;</td>
			<td>10977-023</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">SDF-1&#945;</td>
			<td>Prepared according to reference 8.</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Syringe filter, PES membrane 0.22 um.&#160;&#160;&#160;</td>
			<td>Millipore</td>
			<td>SLGP033RS</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Magnetic Micro Stirring Bars (2 x 7 mm)</td>
			<td>Fisher&#160;</td>
			<td>14-513-63</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Glass vial Kit; SUN-SRi</td>
			<td>Fisher&#160;</td>
			<td>14-823-182</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Delsa Nano C Particle Analyzer&#160;</td>
			<td>Backman Coulter</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Eppendorf UVette Cuvets</td>
			<td>Eppendorf</td>
			<td>952010069</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">4&#8211;20% Mini-PROTEAN TGX Gel</td>
			<td>Bio-Rad</td>
			<td>456-1096</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">GelCode Blue Safe Protein Stain</td>
			<td>Fisher&#160;</td>
			<td>PI-24592</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Molecular Imager VersaDoc MP 4000 System</td>
			<td>BioRad</td>
			<td>170-8640</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Corning Transwell Permeable Supports</td>
			<td>Corning</td>
			<td>3421</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Accuri C6 Flow Cytometer</td>
			<td>BD Biosciences</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dulbecco&#8217;s phosphate buffered saline&#160;</td>
			<td>Sigma</td>
			<td>D8537</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Pyrogent plus kit</td>
			<td>Fisher</td>
			<td>NC9753738</td>
		</tr>
	</tbody>
</table>

preparation and characterization of sdf-1&#945;-chitosan-dextran sulfate nanoparticles

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under appropriate conditions. The glycan nanoparticles are useful carriers for protein factors, which facilitate the in vivo delivery of the proteins and sustain their retention in the targeted tissue. The glycan polyelectrolyte complexes are also ideal for protein delivery, as the incorporation is carried out in aqueous solution, which reduces the likelihood of inactivation of the proteins. Proteins with a heparin-binding site adhere to dextran sulfate readily, and are, in turn, stabilized by the binding. These particles are also less inflammatory and toxic when delivered in vivo. In the protocol described below, SDF-1&#945; (Stromal cell-derived factor-1&#945;), a stem cell homing factor, is first mixed and incubated with dextran sulfate. Chitosan is added to the mixture to form polyelectrolyte complexes, followed by zinc sulfate to stabilize the complexes with zinc bridges. The resultant SDF-1&#945;-DS-CS particles are measured for size (diameter) and surface charge (zeta potential). The amount of the incorporated SDF-1&#945; is determined, followed by measurements of its in vitro release rate and its chemotactic activity in a particle-bound form.

調製されたSDF-1α-DS-CS粒子のサイズとゼータ電位は、粒子分析器を用いて測定される。1、サイズ測定の分析を示す図 。 4反復測定から得られたキュムラント結果から、SDF-1α-DS-CS粒子の平均流体力学的直径は661±8.2（nm）であり、多分散性は0.23±0.02である。ゼータ電位測定の結果を図2に示されている5つ繰り返し測定から、SDF-1α-DS-CS粒子のゼータ電位は、-2...

Watch this Scientific Journal Video about Preparation and Characterization of SDF-1Î±-Chitosan-Dextran Sulfate Nanoparticles at JoVE.com

Preparation and Characterization of SDF-1&amp;#945;-Chitosan-Dextran Sulfate Nanoparticles

The objective of this protocol is to incorporate SDF-1&#945;, a stem cell homing factor, into dextran sulfate-chitosan nanoparticles. The resultant particles are measured for their size and zeta potential, as well as the content, activity, and in vitro release rate of SDF-1&#945; from the nanoparticles.

SDF-1α-キトサン硫酸デキストランナノ粒子の調製とキャラクタリゼーション

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under ...

preparation-characterization-sdf-1-chitosan-dextran-sulfate

Research

JoVE Journal

Chemistry

Preparation and Characterization of SDF-1&#945;-Chitosan-Dextran Sulfate Nanoparticles

12.3K ビュー.  Brigham and Women's Hospital and Harvard Medical School. The objective of this protocol is to incorporate SDF-1α, a stem cell homing factor, into dextran sulfate-chitosan nanoparticles. The resultant particles are measured for their size and zeta potential, as well as the content, activity, and in vitro release rate of SDF-1α from the nanoparticles.

ビデオ: Preparation and Characterization of SDF-1&#945;-Chitosan-Dextran Sulfate Nanoparticles

Preparation of Silica Nanoparticles Through Microwave-assisted Acid-catalysis

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan &#948; solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials&#39; morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by St&#246;ber&#39;s methods, which have smooth surfaces.

Silica nanoparticles were prepared using acid-catalysis of a siloxane precursor and microwave-assisted synthetic techniques resulting in the controlled growth of nanomaterials ranging from 30-250 nm in diameter. The growth dynamics can be controlled by varying the initial silicic acid concentration, time of the reaction, and temperature of reaction.

マイクロ波支援酸 - 触媒反応によりシリカナノ粒子の調製

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle ...

化学

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar concentration forming hydrophobic cores surrounded by hydrophilic shells in aqueous environments. The core of these micelles can be utilized to load hydrophobic, poorly water soluble drugs like docetaxel (DTX) and everolimus (EVR). Systematic characterization of the micelle structure and drug loading capabilities are important before in vitro and in vivo studies can be conducted. The goal of the protocol described herein is to provide the necessary characterization steps to achieve standardized micellar products. DTX and EVR have intrinsic solubilities of 1.9 and 9.6 &#181;g/ml respectively Preparation of these micelles can be achieved through solvent casting which increases the aqueous solubility of DTX and EVR to 1.86 and 1.85 mg/ml, respectively. Drug stability in micelles evaluated at room temperature over 48 hr indicates that 97% or more of the drugs are retained in solution. Micelle size was assessed using dynamic light scattering and indicated that the size of these micelles was below 50 nm and depended on the molecular weight of the polymer. Drug release from the micelles was assessed using dialysis under sink conditions at pH 7.4 at 37 oC over 48 hr. Curve fitting results indicate that drug release is driven by a first order process indicating that it is diffusion driven.

The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

調製とキャラクタリゼーション個々のとマルチ薬ロード物理的に捕捉さ高分子ミセル

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

合成、キャラクタリゼーション、およびハイブリッドのAu / CdSのとAu / ZnSのコア/シェルナノ粒子の機能化

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

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 ...

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

A protocol for in situ aqueous synthesis of a bis(iminoguanidinium) ligand and its utilization in selective separation of sulfate is presented.

ビスiminoguanidiniumリガンドと選択的結晶化により硫酸の分離

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents. Specifically, the increase in local concentration of the paramagnetic species results in a higher signal contrast. Furthermore, this CA provides a longer tissue retention time due to its high molecular weight and size. Here, we demonstrate a convenient procedure for the preparation of macromolecular MRI contrast agents based on poly(amidoamine) (PAMAM) dendrimers with monomacrocyclic DOTA-type chelators (DOTA &#8211; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). The chelating unit was appended by exploiting the reactivity of the isothiocyanate (NCS) group towards the amine surface groups of the PAMAM dendrimer to form thiourea bridges. Dendrimeric products were purified and analyzed by means of nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. Finally, high resolution MR images were recorded and the signal contrasts obtained from the prepared dendrimeric and the commercially available monomeric agents were compared.

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

This protocol describes the preparation and characterization of a dendrimeric magnetic resonance imaging (MRI) contrast agent that carries cyclen-based macrocyclic chelates coordinating paramagnetic gadolinium ions. In a series of MRI experiments in vitro, this agent produced an amplified MRI signal when compared to the commercially available monomeric analogue.

調製と<em&gt;インビトロ</em&gt;磁気共鳴イメージングのためのデンドリマーベースの造影剤のキャラクタリゼーション

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We present methods for depositing and passively manipulating C60 molecules on rippled graphene that advance the pursuit of realizing applications involving 1D C60/graphene hybrid structures. The techniques applied in this exposition are geared towards high vacuum systems with preparation areas capable of supporting molecular deposition as well as thermal annealing of the samples. We focus on C60 deposition at low pressure using a homemade Knudsen cell connected to a scanning tunneling microscopy (STM) system. The number of molecules deposited is regulated by controlling the temperature of the Knudsen cell and the deposition time. One-dimensional (1D) C60 chain structures with widths of two to three molecules can be prepared via tuning of the experimental conditions. The surface mobility of the C60 molecules increases with annealing temperature allowing them to move within the periodic potential of the rippled graphene. Using this mechanism, it is possible to control the transition of 1D C60 chain structures to a hexagonal close packed quasi-1D stripe structure.

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Here we present a protocol for the fabrication of C60/graphene hybrid nanostructures by physical thermal evaporation. Particularly, the proper manipulation of deposition and annealing conditions allow the control over the creation of 1D and quasi 1D C60 structures on rippled graphene.

C60/Graphene ハイブリッド ナノ構造の作製と評価

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We ...

Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution of capping ligands during the synthesis reaction, their role in regulating the nucleation and growth rates of colloidal nanoparticles is not well understood. In this work, we demonstrate a mechanistic investigation of the role of trioctylphosphine (TOP) in Pd nanoparticles in different solvents (toluene and pyridine) using in situ SAXS and ligand-based kinetic modeling. Our results under different synthetic conditions reveal the overlap of nucleation and growth of Pd nanoparticles during the reaction, which contradicts the LaMer-type nucleation and growth model. The model accounts for the kinetics of Pd-TOP binding for both, the precursor and the particle surface, which is essential to capture the size evolution as well as the concentration of particles in situ. In addition, we illustrate the predictive power of our ligand-based model through designing the synthetic conditions to obtain nanoparticles with desired sizes. The proposed methodology can be applied to other synthesis systems and therefore serves as an effective strategy for predictive synthesis of colloidal nanoparticles.

The main goal of this work is to elucidate the role of capping agents in regulating the size of palladium nanoparticles by combining in situ small angle x-ray scattering (SAXS) and ligand-based kinetic modeling.

リガンドを介した核生成とパラジウムの金属ナノ粒子の成長

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution ...

High Resolution Physical Characterization of Single Metallic Nanoparticles

Individual molecules can be detected and characterized by measuring the degree by which they reduce the ionic current flowing through a single nanometer-scale pore. The signal is characteristic of the molecule&#39;s physicochemical properties and its interactions with the pore. We demonstrate that the nanopore formed by the bacterial protein exotoxin Staphylococcus aureus alpha hemolysin (&#945;HL) can detect polyoxometalates (POMs, anionic metal oxygen clusters), at the single molecule limit. Moreover, multiple degradation products of 12-phosphotungstic acid POM (PTA, H3PW12O40) in solution are simultaneously measured. The single molecule sensitivity of the nanopore method allows for POMs to be characterized at significantly lower concentrations than required for nuclear magnetic resonance (NMR) spectroscopy. This technique could serve as a new tool for chemists to study the molecular properties of polyoxometalates or other metallic clusters, to better understand POM synthetic processes, and possibly improve their yield. Hypothetically, the location of a given atom, or the rotation of a fragment in the molecule, and the metal oxidation state could be investigated with this method. In addition, this new technique has the advantage of allowing the real-time monitoring of molecules in solution.&#160;

Here, we present a protocol to detect discrete metal oxygen clusters, polyoxometalates (POMs), at the single molecule limit using a biological nanopore-based electronic platform. The method provides a complementary approach to traditional analytical chemistry tools used in the study of these molecules.

単一金属ナノ粒子の高解像度物理特性評価

Individual molecules can be detected and characterized by measuring the degree by which they reduce the ionic current flowing through a single ...

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of their interactions with cell membranes, lipid bilayers, and viruses. The hydrophilic ligands make these particles colloidally stable in aqueous solutions and the combination with hydrophobic ligands creates an amphiphilic particle that can be loaded with hydrophobic drugs, fuse with the lipid membranes, and resist nonspecific protein adsorption. Many of these properties depend on nanoparticle size and the composition of the ligand shell. It is, therefore, crucial to have a reproducible synthetic method and reliable characterization techniques that allow the determination of nanoparticle properties and the ligand shell composition. Here, a one-phase chemical reduction, followed by a thorough purification to synthesize these nanoparticles with diameters below 5 nm, is presented. The ratio between the two ligands on the surface of the nanoparticle can be tuned through their stoichiometric ratio used during synthesis. We demonstrate how various routine techniques, such as transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), and ultraviolet-visible (UV-Vis) spectrometry, are combined to comprehensively characterize the physicochemical parameters of the nanoparticles.

Amphiphilic gold nanoparticles can be used in many biological applications. A protocol to synthesize gold nanoparticles coated by a binary mixture of ligands and a detailed characterization of these particles is presented.

親和性金ナノ粒子の合成と特性化

Gold nanoparticles covered with a mixture of 1-octanethiol (OT) and 11-mercapto-1-undecane sulfonic acid (MUS) have been extensively studied because of ...