Funding for this research was provided by the Italian Ministry of Health under the frame of EuroNanoMed II (European Innovative Research &amp; Technological Development Projects in Nanomedicine, project title: ''InNaSERSS'').

1. Sintesi di oro Nanorods Nota: Usare acqua altamente purificata in tutto. <ol><li> Preparazione dei semi oro <ol><li> Sciogliere 364,4 mg di esadeciltrimetilammonio bromuro (CTAB) in 5 ml di acqua, sotto ultrasuoni a 40 ° C fino a quando la soluzione diventa limpida. Sia la soluzione CTAB raffreddare a temperatura ambiente. </li><li> Separatamente, preparare 5 ml di acido tetracloroaurico (HAuCl4) in acqua (0,5 mM). </li><li> Aggiungere la soluzione HAuCl4 alla soluzione CTAB sotto agitazione magnetica vigorosa, mantenendo costante la temperatura a 27 ° C. </li><li> Preparare 600 ml di boroidruro di sodio (NaBH4) soluzione in acqua (10 mM) a 4 ° C. Aggiungere questa soluzione alla miscela sotto agitazione vigorosa. Controllare se il colore della soluzione cambia immediatamente dal giallo al marrone. </li><li> Mescolare la sospensione per 20 minuti prima dell&#39;uso. Conservare la sospensione semi per non più di 24 ore a temperatura. </li><li> Verificare le dimensioni dei semi utilizzando uno spettrofotometro UV-Vis. Assicurarsi che i semi sono abbastanza piccolo (circa 2 nm) da utilizzare nella preparazione di nanotubi di oro mediante spettroscopia UV-visibile. Nota: Spectrum deve essere simile a quanto riportato in figura 1 semi maggiore identificate dalla presenza di un picco plasmonico circa 505-520 nm non devono essere utilizzati perché sono in grado di produrre nanoparticelle sferiche.. </li></ol></li><li> Preparazione della &quot;soluzione di crescita&quot; di nanotubi d&#39;oro. <ol><li> Sciogliere 182,2 mg CTAB insieme con 22 mg di idrochinone in 5 ml di acqua a 40 ° C con ultrasuoni. Raffreddare la soluzione a 27 ° C. </li><li> Preparare 200 ml di 4 mm nitrato d&#39;argento (AgNO3) soluzione. </li><li> Separatamente, preparare 5 ml di soluzione 1 mM di acido tetracloroaurico (HAuCl4). </li><li> In primo luogo aggiungere la soluzione di nitrato d&#39;argento preparata al punto 1.2.2. Quindi, aggiungere il HAuCl 4 soluzione preparata al punto 1.2.3 alla soluzione di CTAB e idrochinone preparato al punto 1.2.1 sotto agitazione magnetica. </li><li> Subito dopo, aggiungere sotto agitazione magnetica 12 microlitri della sospensione semi precedentemente preparata secondo il protocollo riportati al punto 1.1 e lasciare l&#39;inizio reazione. Controllare se la sospensione cambia colore in circa 30 min. </li><li> Controllare la formazione dei nanotubi controllando lo spettro UV-visibile della sospensione, come descritto nella sezione 4, ogni 5 min. Procedere fino spettro è stabile. Per consentire la formazione completa dei nanotubi, lasciare la sospensione sotto agitazione per ulteriori 30 min (Figura 2). </li><li> Dividere la sospensione nei tubi (1 ml di sospensione per ogni provetta) e centrifugare a 10.000 xg per 10 min. nanorods oro formano un precipitato scuro sul fondo della provetta. </li><li> Risospendere il precipitato di ogni tubo in 1 ml di acqua. Mescolare il contenuto dei tubi e memorizzare il suspensione di nanotubi d&#39;oro a temperatura ambiente. </li><li> Caratterizzare i nanotubi ottenuti mediante spettroscopia e trasmissione microscopia elettronica UV-visibile come descritto nel paragrafo 4 (figura 3). </li></ol></li></ol> 2. Ottimizzazione del rapporto di formato di nanotubi variando la concentrazione di ioni Ag + <ol><li> Preparare una soluzione di nitrato d&#39;argento con una concentrazione di 4 mM, sciogliendo 3,4 mg AgNO 3 a 5 ml di acqua. </li><li> Preparare in tre diverse fiale la soluzione con CTAB e idrochinone come descritto nella sezione 1.2.1 e aggiungere rispettivamente 100 microlitri, 150 microlitri o 200 ml di soluzione di nitrato d&#39;argento. </li><li> Aggiungere la soluzione 4 HAuCl secondo preparata al punto 1.2.3 e procedere con la preparazione di nanotubi d&#39;oro come descritto dal punto 1.2.5. </li><li> Caratterizzare i nanotubi ottenuti mediante spettroscopia UV-visibile e microscopia elettronica a trasmissione. Fiale con minori quantità di Ag + si riproduce dei nanotubi brevi (proporzioni 2 e 2,2 rispettivamente) (Figura 4). </li></ol> 3. Mettere a punto il rapporto di aspetto di nanotubi variando la concentrazione di CTAB <ol><li> Preparare diversi lotti di nanotubi d&#39;oro con diverse concentrazioni di CTAB nella &quot;soluzione di crescita&quot;. Utilizzare concentrazioni da 10 mm a 100 mm per la produzione di nanotubi d&#39;oro che hanno diverse dimensioni e proporzioni. Le concentrazioni di CTAB utilizzati in ciascun esperimento sono riassunti in tabella 1 con la corrispondente quantità di milligrammi utilizzato. Sciogliere le diverse quantità di CTAB sempre con 22 mg di idrochinone in 5 ml di acqua. </li><li> Aggiungere 200 ml di soluzione di nitrato d&#39;argento (preparato secondo punto 1.2.2) e 5 ml di soluzione HAuCl4 (preparato secondo quanto descritto al punto 1.2.3) in ciascuna fiala sotto agitazione magnetica. </li><li> Aggiungere 12 ml di sospensione semi e osservare il cambiamento di colore della miscela finale. </li><li> Stopl&#39;agitazione quando il colore della sospensione e lo spettro UV-visibile sono stabilizzate; il tempo di reazione dipende dalla concentrazione CTAB nella soluzione di crescita. </li><li> Centrifugare a 10.000 xg per 10 min e risospendere in acqua. </li><li> Caratterizzare i nanotubi ottenuti mediante spettroscopia UV-visibile e microscopia elettronica a trasmissione. Una concentrazione più bassa di CTAB si tradurrà in nanotubi più brevi, mentre una maggiore concentrazione darà nanotubi più lunghi ma più grandi. Al contrario le proporzioni dei nanotubi sarà superiore nell&#39;intervallo di circa 40-50 mm e diminuisce sia a concentrazioni inferiori e superiori (Figura 5 e Figura 6). </li></ol> 4. Caratterizzazione di oro Nanorods <ol><li> Spettroscopia UV-visibile <ol><li> Diluire 100 ml di soluzione di nanotubi con 400 ml di acqua in un materiale plastico micro-cuvetta e acquisire lo spettro di assorbimento UV-visibile (lunghezza d&#39;onda tra 400 e 840 nm)secondo il protocollo del produttore. </li><li> Raccogliere spettri UV-visibile (lunghezza d&#39;onda tra 400 e 840 nm) della soluzione di crescita ogni 5 minuti per studiare la cinetica della reazione. </li></ol></li><li> Microscopia elettronica a trasmissione (TEM) <ol><li> Raccogliere immagini TEM di ciascun campione di nanotubi, per la misura della dimensione e del rapporto di aspetto dei nanotubi ottenuti. Preparare i campioni mettendo una goccia di sospensione (4 ml) su un ultra-sottili griglie di rame 200-maglia Formvar a polvere e lasciare asciugare all&#39;aria a 4 ° C. Analizzare il campione a TEM utilizzando una tensione di accelerazione di 200 kV secondo il protocollo del produttore. </li></ol></li></ol>

<ol>
	<li>Zhou, W., Gao, X., Liu, D., Chen, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gold+Nanoparticles+for+In+Vitro+Diagnostics.">Gold Nanoparticles for In Vitro Diagnostics.</a> Chem Rev. 115 (19), 10575-10636 (2015).</li><li>Bao, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gold+nanoprisms+as+optoacoustic+signal+nanoamplifiers+for+in+vivo+bioimaging+of+gastrointestinal+cancers.">Gold nanoprisms as optoacoustic signal nanoamplifiers for in vivo bioimaging of gastrointestinal cancers.</a> Small. 9 (1), 68-74 (2013).</li><li>Han, G., Ghosh, P., Rotello, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functionalized+gold+nanoparticles+for+drug+delivery.">Functionalized gold nanoparticles for drug delivery.</a> Nanomedicine. 2 (1), 113-123 (2007).</li><li>Choi, W. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+regression+in+vivo+by+photothermal+therapy+based+on+gold-nanorod-loaded,+functional+nanocarriers.">Tumor regression in vivo by photothermal therapy based on gold-nanorod-loaded, functional nanocarriers.</a> ACS Nano. 5 (3), 1995-2003 (2011).</li><li>Langille, M. R., Personick, M. L., Zhang, J., Mirkin, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defining+Rules+for+the+Shape+Evolution+of+Gold+Nanoparticles+.">Defining Rules for the Shape Evolution of Gold Nanoparticles .</a> J. Am. Chem. Soc. 134 (35), 14542-14554 (2012).</li><li>Lohse, S. E., Murphy, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Quest+for+Shape+Control:+A+History+of+Gold+Nanorod+Synthesis.">The Quest for Shape Control: A History of Gold Nanorod Synthesis.</a> Chem. Mater. 25 (8), 1250-1261 (2013).</li><li>Weissleder, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+clearer+vision+for+in+vivo+imaging.">A clearer vision for in vivo imaging.</a> Nat. Biotech. 19 (4), 316-317 (2001).</li><li>Sau, T. K., Murphy, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Seeded+High+Yield+Synthesis+of+Short+Au+Nanorods+in+Aqueous+Solution.">Seeded High Yield Synthesis of Short Au Nanorods in Aqueous Solution.</a> Langmuir. 20 (15), 6414-6420 (2004).</li><li>Ratto, F., Matteini, P., Rossi, F., Pini, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size+and+shape+control+in+the+overgrowth+of+gold+nanorods.">Size and shape control in the overgrowth of gold nanorods.</a> J. Nanopart. Res. 12, 2029-2036 (2010).</li><li>Morasso, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+size+and+aspect+ratio+in+hydroquinone-based+synthesis+of+gold+nanorods.">Control of size and aspect ratio in hydroquinone-based synthesis of gold nanorods.</a> J. Nanopart. Res. 17, 330-337 (2015).</li><li>Vigderman, L., Zubarev, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-yield+synthesis+of+gold+nanorods+with+longitudinal+SPR+peak+greater+than+1200+nm+using+hydroquinone+as+a+reducing+agent.">High-yield synthesis of gold nanorods with longitudinal SPR peak greater than 1200 nm using hydroquinone as a reducing agent.</a> Chem. Mater. 25 (8), 1450-1457 (2013).</li><li>Walsh, M. J., Barrow, S. J., Tong, W., Funston, A. M., Etheridge, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Symmetry+breaking+and+silver+in+gold+nanorod+growth.">Symmetry breaking and silver in gold nanorod growth.</a> ACS Nano. 9 (1), 715-724 (2015).</li></ol>

The authors have nothing to disclose.

Il protocollo qui presentata si applica idrochinone, una molecola aromatica caratterizzata da un potenziale di riduzione deboli, per produrre nanorods oro. Ci sono due vantaggi principali del presente protocollo verso la via di sintesi più comunemente impiegato basato sull&#39;uso di acido ascorbico: il primo è che l&#39;idrochinone è in grado di ridurre quasi quantitativamente gli ioni d&#39;oro che permettono la produzione di una maggiore quantità di nanotubi oro 11 La. quest&#39;ultimo è dato dal fatt...

nanoparticelle di oro (AuNPs) sono una delle nanostrutture più diffuse e promettenti per essere utilizzato in applicazioni biomediche. Il loro impiego è indispensabile molti point-of-care la diagnosi in vitro prodotti 1 Sono stati proposti come uno strumento efficace per una serie di altre applicazioni diverse:. Come agente di contrasto in studi di imaging, 2 come sistema drug delivery 3 e come farmaci per termoterapia indotta dalla luce (o terapia fototermica). 4 la grande potenzialità di AuNPs è guidato, negli ultimi venti anni, intensa ricerca sullo sviluppo di nuova sintesi che è in grado di aumentare il controllo sulla dimensione e forma ottenuta. 5 Questo perché diversi tipi di AuNPs infatti, sono più adatti di altri per applicazioni specifiche. Tra le diverse nanostrutture oro, nanorods oro (AuNRs) sono emersi come uno dei sistemi più interessanti. AuNRs sono caratterizzati da due plasmopicchi nic associati con l&#39;oscillazione degli elettroni lungo la longitudinale e gli assi trasversali, rispettivamente. 6 è particolarmente importante che la posizione del picco più intenso longitudinale può essere sintonizzato precisamente tra 620 e 800 nm, a seconda del formato delle aste . Questa regione corrisponde finestra biologica, 7 dove i tessuti umani quasi non assorbono la luce, consentendo lo sviluppo di una serie di applicazioni fotoniche in vivo coinvolgono AuNPs. Nonostante il grande interesse per questo tipo di nanostrutture, i protocolli di sintesi per la preparazione di AuNRs soffrono di diversi limiti. Nella maggior parte dei casi, nanorods vengono preparati secondo un metodo in due fasi sviluppato da Sau e collaboratori. 8 Nella loro protocollo, nanorods sono sintetizzati riducendo ioni di oro con acido ascorbico in presenza di semi oro preformati, gli ioni d&#39;argento e una grande quantità di esadecil trimetilammonio bromuro (CTAB), ACtensioattivo lineari ationic. Lo svantaggio di questo protocollo è che la resa di riduzione di ioni oro è relativamente bassa (circa 20%) 9 e che una quantità elevata di CTAB, un reagente costoso che rappresenta più della metà del costo totale per i reagenti nella sintesi, è necessario. Lo sviluppo di un nuovo e più efficace via di sintesi è considerato quindi ad essere una necessità importante, permettendo la diffusione di approcci biomedici basati su AuNRs. Nella prima parte del presente documento, presentiamo un protocollo ottimizzato per la preparazione di AuNR avente una proporzione di circa tre. La sintesi si basa sull&#39;uso di idrochinone come agente riducente delicato e permette la preparazione di AuNR con una riduzione quasi quantitativa di ioni di oro, facendo uso di una quantità ridotta di CTAB. 10 Questo protocollo per la preparazione dei AuNRs si riferiscono su un approccio a due fasi in cui i semi oro sono utilizzati in un &quot;sol crescitaution &quot;. Nella seconda parte, mostriamo come regolare con precisione il rapporto di dimensioni e aspetto del AuNR ottenuto in due modi. Il primo modo, simile al protocollo standard a base di acido ascorbico, è quello di variare la quantità di ioni d&#39;argento presenti nel &quot;soluzione di crescita&quot;. Il secondo modo è basato sulla variazione della quantità di CTAB che può essere ridotto fino ad una concentrazione di 10 mM (vicino alla concentrazione micellare critica comunicate dal fornitore) per ottenere nanotubi brevi ben definiti.

<table border="0" cellpadding="0" cellspacing="0" width="756">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gold(III) chloride trihydrate</td>
			<td style="width:115px;">Sigma Aldrich</td>
			<td style="width:99px;">520918</td>
			<td style="width:327px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hydroquinone</td>
			<td>Sigma Aldrich</td>
			<td>H17902</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Silver Nitrate</td>
			<td>Sigma Aldrich</td>
			<td>209139</td>
			<td>toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium Borohydride</td>
			<td>Sigma Aldrich</td>
			<td>480886</td>
			<td></td>
		</tr>
		<tr height="148">
			<td height="148" style="height:148px;width:216px;">Hexadecyltrimethylammonium bromide (CTAB)</td>
			<td>Sigma Aldrich</td>
			<td>H5882</td>
			<td style="width:327px;">Acute Tox. (oral). In this study we tested three different batches of CTAB (H5882) from Sigma Aldrich. Two of them were marked as made in China while one as made in India. In our experience only the batches marked as made in China were effective for the preparation of AuNR</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Spectrophotometer</td>
			<td style="width:115px;">Thermo scientific&#160;</td>
			<td style="width:99px;">Nanodrop 2000C</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">TEM</td>
			<td style="width:115px;">JEOL</td>
			<td>2100</td>
			<td></td>
		</tr>
	</tbody>
</table>

hydroquinone based synthesis of gold nanorods

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag+) present in the "growth solution". By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM.

UV spettri visibile dei semi oro può essere visto in Figura 1. UV spettri visibile acquisite in tempi diversi dopo l&#39;iniezione dei semi oro sono rappresentati in Figura 2. Immagini UV spettri visibili e microscopica elettronica a trasmissione (TEM) dei nanotubi oro ottenuti sono mostrati in figura 3. microscopica UV visibile spettri e trasmissione di elettroni (TEM) immagini di nanotubi oro con proporzioni diverse ottenuto variando ...

Watch this Scientific Journal Video about Hydroquinone Based Synthesis of Gold Nanorods at JoVE.com

Hydroquinone Based Synthesis of Gold Nanorods

Questo documento descrive un protocollo per la sintesi di nanotubi oro, basato sull&#39;utilizzo di idrochinone come agente riducente, più i vari meccanismi di controllo loro dimensioni e proporzioni.

Idrochinone Based Sintesi di oro Nanorods

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the ...

hydroquinone-based-synthesis-of-gold-nanorods

Research

JoVE Journal

Chemistry

13.6K Views.  Fondazione Don Carlo Gnocchi ONLUS (Don Carlo Gnocchi Foundation).  Questo documento descrive un protocollo per la sintesi di nanotubi oro, basato sull'utilizzo di idrochinone come agente riducente, più i vari meccanismi di controllo loro dimensioni e proporzioni. 

Video: Hydroquinone Based Synthesis of Gold Nanorods

Template Directed Synthesis of Plasmonic Gold Nanotubes with Tunable IR Absorbance

A nearly parallel array of pores can be produced by anodizing aluminum foils in acidic environments1, 2. Applications of anodic aluminum oxide (AAO) membranes have been under development since the 1990's and have become a common method to template the synthesis of high aspect ratio nanostructures, mostly by electrochemical growth or pore-wetting. Recently, these membranes have become commercially available in a wide range of pore sizes and densities, leading to an extensive library of functional nanostructures being synthesized from AAO membranes. These include composite nanorods, nanowires and nanotubes made of metals, inorganic materials or polymers 3-10. Nanoporous membranes have been used to synthesize nanoparticle and nanotube arrays that perform well as refractive index sensors, plasmonic biosensors, or surface enhanced Raman spectroscopy (SERS) substrates 11-16, as well as a wide range of other fields such as photo-thermal heating 17, permselective transport 18, 19, catalysis 20, microfluidics 21, and electrochemical sensing 22, 23. Here, we report a novel procedure to prepare gold nanotubes in AAO membranes. Hollow nanostructures have potential application in plasmonic and SERS sensing, and we anticipate these gold nanotubes will allow for high sensitivity and strong plasmon signals, arising from decreased material dampening 15.

Solution-suspendable gold nanotubes with controlled dimensions can be synthesized by electrochemical deposition in porous anodic aluminum oxide (AAO) membranes using a hydrophobic polymer core. Gold nanotubes and nanotube arrays hold promise for applications in plasmonic biosensing, surface-enhanced Raman spectroscopy, photo-thermal heating, ionic and molecular transport, microfluidics, catalysis and electrochemical sensing.

Modello Regia Sintesi di nanotubi d&#39;oro plasmoniche con Tunable Assorbanza IR

A nearly parallel array of pores can be produced by anodizing aluminum foils in acidic environments1, 2. Applications of anodic aluminum oxide (AAO) ...

Ricerca

Chimica

Synthesis and Catalytic Performance of Gold Intercalated in the Walls of Mesoporous Silica

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties of the materials were investigated. We used a one pot sol-gel approach to intercalate gold nano particles in the walls of mesoporous silica. To start with the synthesis, P123 was used as template to form micelles. Then TESPTS was used as a surface modification agent to intercalate gold nano particles. Following this process, TEOS was added in as a silica source which underwent a polymerization process in acid environment. After hydrothermal processing and calcination, the final product was acquired. Several techniques were utilized to characterize the porosity, morphology and structure of the gold intercalated mesoporous silica. The results showed a stable structure of mesoporous silica after gold intercalation. Through the oxidation of benzyl alcohol as a benchmark reaction, the GMS materials showed high selectivity and recyclability.

Here, we present a protocol with a sol-gel process to synthesize gold intercalated in the walls of mesoporous materials (GMS), which is confirmed to possess a mesoporous matrix with gold intercalated in the walls imparting great stability and recyclability.

Sintesi e prestazioni catalitica dell&#39;oro intercalata nelle Mura di mesoporosi silice

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties ...

A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like oligomeric clusters of these yellow nanoparticles of narrow size distribution are synthesized under ambient conditions via two methods. The delay-time method controls the number of subunits in the oligoclusters by varying the time between the addition of HAuCl4 to alkaline solution and the subsequent addition of reducing agent, NaSCN. The yellow oligoclusters produced range in size from ~3 to ~25 nm. This size range can be further extended by an add-on method utilizing hydroxylated gold chloride (Na+[Au(OH4-x)Clx]-) to auto-catalytically increase the number of subunits in the as-synthesized oligocluster nanoparticles, providing a total range of 3 nm to 70 nm. The crude oligocluster preparations display narrow size distributions and do not require further fractionation for most purposes. The oligoclusters formed can be concentrated &#62;300 fold without aggregation and the crude reaction mixtures remain stable for weeks without further processing. Because these oligomeric clusters can be concentrated before derivatization they allow expensive derivatizing agents to be used economically. In addition, we present two models by which predictions of particle size can be made with great accuracy.

We describe a simple method for producing highly stable oligomeric clusters of gold nanoparticles via the reduction of chloroauric acid (HAuCl4) with sodium thiocyanate (NaSCN). The oligoclusters have a narrow size distribution and can be produced with a wide range of sizes and surface coats.

Un metodo semplice per la dimensione sintesi controllata di stabili oligomeriche Grappoli di oro nanoparticelle in condizioni ambientali

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like ...

Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods

We demonstrate a procedure for the photochemical oxidative growth of iridium oxide catalysts on the surface of seeded cadmium selenide-cadmium sulfide (CdSe@CdS) nanorod photocatalysts. Seeded rods are grown using a colloidal hot-injection method and then moved to an aqueous medium by ligand exchange. CdSe@CdS nanorods, an iridium precursor and other salts are mixed and illuminated. The deposition process is initiated by absorption of photons by the semiconductor particle, which results with formation of charge carriers that are used to promote redox reactions. To insure photochemical oxidative growth we used an electron scavenger. The photogenerated holes oxidize the iridium precursor, apparently in a mediated oxidative pathway. This results in the growth of high quality crystalline iridium oxide particles, ranging from 0.5 nm to about 3 nm, along the surface of the rod. Iridium oxide grown on CdSe@CdS heterostructures was studied by a variety of characterization methods, in order to evaluate its characteristics and quality. We explored means for control over particle size, crystallinity, deposition location on the CdS rod, and composition. Illumination time and excitation wavelength were found to be key parameters for such control. The influence of different growth conditions and the characterization of these heterostructures are described alongside a detailed description of their synthesis. Of significance is the fact that the addition of iridium oxide afforded the rods astounding photochemical stability under prolonged illumination in pure water (alleviating the requirement for hole scavengers).

A protocol for the photochemical oxidative growth of small crystalline iridium oxide nanoparticles on the surface of CdSe@CdS seeded rod nanoparticles is presented.

Fotochimica ossidativa crescita di Iridium ossido di nanoparticelle su CdSe @ CdS Nanorods

We demonstrate a procedure for the photochemical oxidative growth of iridium oxide catalysts on the surface of seeded cadmium selenide-cadmium sulfide ...

Synthesis and Evaluation of a Ruthenium-based Mitochondrial Calcium Uptake Inhibitor

We detail the synthesis and purification of a mitochondrial calcium uptake inhibitor, [(OH2)(NH3)4Ru(&#181;-O)Ru(NH3)4(OH2)]5+. The optimized synthesis of this compound commences from [Ru(NH3)5Cl]Cl2 in 1 M NH4OH in a closed container, yielding a green solution. Purification is accomplished with cation-exchange chromatography. This compound is characterized and verified to be pure by UV-vis and IR spectroscopy. The mitochondrial calcium uptake inhibitory properties are assessed in permeabilized HeLa cells by fluorescence spectroscopy.

A protocol for the synthesis, purification, and characterization of a ruthenium-based inhibitor of mitochondrial calcium uptake is presented. A procedure to evaluate its efficacy in permeabilized mammalian cells is demonstrated.

Sintesi e valutazione di un inibitore di assorbimento di calcio mitocondriale a base di rutenio

We detail the synthesis and purification of a mitochondrial calcium uptake inhibitor, [(OH2)(NH3)4Ru(&#181;-O)Ru(NH3)4(OH2)]5+. The optimized synthesis of ...

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity and convenient colorimetric readout. However, high densities of nanoparticles are typically needed for detection. The available synthesis-based enhancement protocols are either limited to gold and silver nanoparticles or rely on precise enzymatic control and optimization. Here, we present a protocol to enhance the colorimetric readout of gold, silver, silica, and iron oxide nanoprobes. It was observed that the colorimetric signal can be improved by up to a 10000-fold factor. The basis for such signal enhancement strategies is the chemical reduction of Au3+ to Au0. There are several chemical reactions that enable the reduction of Au3+ to Au0. In the protocol, Good&#39;s buffers and H2O2 are used and it is possible to favor the deposition of Au0 onto the surface of existing nanoprobes, in detriment of the formation of new gold nanoparticles. The protocol consists of the incubation of the microarray with a solution consisting of chloroauric acid and H2O2 in 2-(N-morpholino)ethanesulfonic acid pH 6 buffer following the nanoprobe-based detection assay. The enhancement solution can be applied to paper and glass-based sensors. Moreover, it can be used in commercially available immunoassays as demonstrated by the application of the method to a commercial allergen microarray. The signal development requires less than 5 min of incubation with the enhancement solution and the readout can be assessed by naked eye or low-end image acquisition devices such as a table-top scanner or a digital camera.

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

In this work, a protocol for signal enhancement of nanoprobe-based biosensing is presented. The protocol is based on the reduction of chloroauric acid onto the surface of existing nanoprobes that consist of gold, silver, silica or iron-oxide nanoparticles.

Segnale Nanosonda rapido aumento di sintesi di nanoparticelle di oro In Situ

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity ...

Synthesis of Bimetallic Pt/Sn-based Nanoparticles in Ionic Liquids

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular physico-chemical properties of ionic liquids (ILs) are exploited to control both nucleation and growth processes. The nanoparticles form colloidal sols of very high colloidal stability in the IL, which is particularly interesting in view of their use as quasi-homogeneous catalysts. Procedures for both nanoparticle extraction in conventional solvents and for nanoparticle precipitation are presented. The size, structure and composition of the synthesized nanocrystals are confirmed using inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX). By this, we show that the nanocrystals are random-type alloy and of small (2-3 nm) size. The catalytic activity and selectivity in the hydrogenation of &#945;,&#946;-unsaturated aldehydes is tested in a semi-continuous batch-type reactor. In this context, the bimetallic Pt/Sn-based nanoparticles reveal a high selectivity towards the unsaturated alcohol.

A protocol for the synthesis of bimetallic nanoparticles in ionic liquids and the procedure of their catalytic testing in the selective hydrogenation of unsaturated aldehydes are described.

Sintesi di nanoparticelle bimetalliche Pt/Sn-basato in liquidi ionici

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular ...

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.

Sintesi e caratterizzazione delle nanoparticelle d'oro dell'anfifile

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

Assembly of Gold Nanorods into Chiral Plasmonic Metamolecules Using DNA Origami Templates

The inherent addressability of DNA origami structures makes them ideal templates for the arrangement of metal nanoparticles into complex plasmonic nanostructures. The high spatial precision of a DNA origami-templated assembly allows controlling the coupling between plasmonic resonances of individual particles and enables tailoring optical properties of the constructed nanostructures. Recently, chiral plasmonic systems attracted a lot of attention due to the strong correlation between the spatial configuration of plasmonic assemblies and their optical responses (e.g., circular dichroism [CD]). In this protocol, we describe the whole workflow for the generation of DNA origami-based chiral assemblies of gold nanorods (AuNRs). The protocol includes a detailed description of the design principles and experimental procedures for the fabrication of DNA origami templates, the synthesis of AuNRs, and the assembly of origami-AuNR structures. In addition, the characterization of structures using transmission electron microscopy (TEM) and CD spectroscopy is included. The described protocol is not limited to chiral configurations and can be adapted for the construction of various plasmonic architectures.

We describe the detailed protocol for the DNA origami-based assembly of gold nanorods into chiral plasmonic metamolecules with strong chiroptical responses. The protocol is not limited to chiral configurations and can be easily adapted for the fabrication of various plasmonic architectures.

Assemblaggio di nanorod oro in Metamolecules plasmoniche chirale utilizzando modelli di Origami del DNA

The inherent addressability of DNA origami structures makes them ideal templates for the arrangement of metal nanoparticles into complex plasmonic ...

Photodeposition of Pd onto Colloidal Au Nanorods by Surface Plasmon Excitation

A protocol is described to photocatalytically guide Pd deposition onto Au nanorods (AuNR) using surface plasmon resonance (SPR). Excited plasmonic hot electrons upon SPR irradiation drive reductive deposition of Pd on colloidal AuNR in the presence of [PdCl4]2-. Plasmon-driven reduction of secondary metals potentiates covalent, sub-wavelength deposition at targeted locations coinciding with electric field &#8220;hot-spots&#8221; of the plasmonic substrate using an external field (e.g., laser). The process described herein details a solution-phase deposition of a catalytically-active noble metal (Pd) from a transition metal halide salt (H2PdCl4) onto aqueously-suspended, anisotropic plasmonic structures (AuNR). The solution-phase process is amenable to making other bimetallic architectures. Transmission UV-vis monitoring of the photochemical reaction, coupled with ex situ XPS and statistical TEM analysis, provide immediate experimental feedback to evaluate properties of the bimetallic structures as they evolve during the photocatalytic reaction. Resonant plasmon irradiation of AuNR in the presence of [PdCl4]2- creates a thin, covalently-bound Pd0 shell without any significant dampening effect on its plasmonic behavior in this representative experiment/batch. Overall, plasmonic photodeposition offers an alternative route for high-volume, economical synthesis of optoelectronic materials with sub-5 nm features (e.g., heterometallic photocatalysts or optoelectronic interconnects).

A protocol for anisotropic photodeposition of Pd onto aqueously-suspended Au nanorods via localized surface plasmon excitation is presented.

Fotodeposizione di Pd su Colloidal Au Nanorods di Surface Plasmon Excitation

A protocol is described to photocatalytically guide Pd deposition onto Au nanorods (AuNR) using surface plasmon resonance (SPR). Excited plasmonic hot ...

Idrochinone Based Sintesi di oro Nanorods

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