Name: hydroquinone based synthesis of gold nanorods
Uploaded: 2016-08-10T14:00:00.000+00:00
Duration: 8 min 55 s
Description: Watch this Scientific Journal Video about Hydroquinone Based Synthesis of Gold Nanorods at JoVE.com

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>

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	<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><tbody><tr><td>Gold(III) chloride trihydrate</td><td>Sigma Aldrich</td><td>520918</td><td></td></tr><tr><td>Hydroquinone</td><td>Sigma Aldrich</td><td>H17902</td><td></td></tr><tr><td>Silver Nitrate</td><td>Sigma Aldrich</td><td>209139</td><td>toxic</td></tr><tr><td>Sodium Borohydride</td><td>Sigma Aldrich</td><td>480886</td><td></td></tr><tr><td>Hexadecyltrimethylammonium bromide (CTAB)</td><td>Sigma Aldrich</td><td>H5882</td><td>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><td>Spectrophotometer</td><td>Thermo scientific&amp;nbsp;</td><td>Nanodrop 2000C</td><td></td></tr><tr><td>TEM</td><td>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

Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method

The physical, chemical and optical properties of nano-scale colloids depend on their material composition, size and shape 1-5. There is a great interest in using nano-colloids for photo-thermal ablation, drug delivery and many other biomedical applications 6. Gold is particularly used because of its low toxicity 7-9. A property of metal nano-colloids is that they can have a strong surface plasmon resonance 10. The peak of the surface plasmon resonance mode depends on the structure and composition of the metal nano-colloids. Since the surface plasmon resonance mode is stimulated with light there is a need to have the peak absorbance in the near infrared where biological tissue transmissivity is maximal 11, 12.
We present a method to synthesize star shaped colloidal gold, also known as star shaped nanoparticles 13-15 or nanostars 16. This method is based on a solution containing silver seeds that are used as the nucleating agent for anisotropic growth of gold colloids 17-22. Scanning electron microscopy (SEM) analysis of the resulting gold colloid showed that 70 % of the nanostructures were nanostars. The other 30 % of the particles were amorphous clusters of decahedra and rhomboids. The absorbance peak of the nanostars was detected to be in the near infrared (840 nm). Thus, our method produces gold nanostars suitable for biomedical applications, particularly for photo-thermal ablation.

We synthesized star shaped gold nanostars using a silver seed mediated growth method. The diameter of the nanostars ranges from 200 to 300 nm and the number of tips vary from 7 to 10. The nanoparticles have a broad surface plasmon resonance mode centered in the near infrared.

Sintesi Nanostar oro con un metodo d&#39;argento crescita Seed Mediated

The physical, chemical and optical properties of nano-scale colloids depend on their material composition, size and shape 1-5. There is a great interest ...

Bioingegneria

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.

Sintesi, Caratterizzazione, e funzionalizzazione di ibrida UA / CdS e Au / ZnS core / shell nanoparticelle

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

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 ...

In Situ Synthesis of Gold Nanoparticles without Aggregation in the Interlayer Space of Layered Titanate Transparent Films

Combinations of metal oxide semiconductors and gold nanoparticles (AuNPs) have been investigated as new types of materials. The in situ synthesis of AuNPs within the interlayer space of semiconducting layered titania nanosheet (TNS) films was investigated here. Two types of intermediate films (i.e., TNS films containing methyl viologen (TNS/MV2+) and 2-ammoniumethanethiol (TNS/2-AET+)) were prepared. The two intermediate films were soaked in an aqueous tetrachloroauric(III) acid (HAuCl4) solution, whereby considerable amounts of Au(III) species were accommodated within the interlayer spaces of the TNS films. The two types of obtained films were then soaked in an aqueous sodium tetrahydroborate (NaBH4) solution, whereupon the color of the films immediately changed from colorless to purple, suggesting the formation of AuNPs within the TNS interlayer. When only TNS/MV2+ was used as the intermediate film, the color of the film gradually changed from metallic purple to dusty purple within 30 min, suggesting that aggregation of AuNPs had occurred. In contrast, this color change was suppressed by using the TNS/2-AET+ intermediate film, and the AuNPs were stabilized for over 4 months, as evidenced by the characteristic extinction (absorption and scattering) band from the AuNPs.

In Situ Synthesis of Gold Nanoparticles without Aggregation in the Interlayer Space of Layered Titanate Transparent Films

Here, we present a protocol for the in situ synthesis of gold nanoparticles (AuNPs) within the interlayer space of layered titanate films without the aggregation of AuNPs. No spectral change was observed even after 4 months. The synthesized material has expected applications in catalysis, photo-catalysis, and the development of cost-effective plasmonic devices.

In Situ Sintesi di oro nanoparticelle senza aggregazione nel Interfalda spazio di Layered titanato pellicole trasparenti

Combinations of metal oxide semiconductors and gold nanoparticles (AuNPs) have been investigated as new types of materials. The in situ synthesis of AuNPs ...

Ingegneria

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 ...

Preparation and Photoacoustic Analysis of Cellular Vehicles Containing Gold Nanorods

Gold nanorods are attractive for a range of biomedical applications, such as the photothermal ablation and the photoacoustic imaging of cancer, thanks to their intense optical absorbance in the near-infrared window, low cytotoxicity and potential to home into tumors. However, their delivery to tumors still remains an issue. An innovative approach consists of the exploitation of the tropism of tumor-associated macrophages that may be loaded with gold nanorods in vitro. Here, we describe the preparation and the photoacoustic inspection of cellular vehicles containing gold nanorods. PEGylated gold nanorods are modified with quaternary ammonium compounds, in order to achieve a cationic profile. On contact with murine macrophages in ordinary Petri dishes, these particles are found to undergo massive uptake into endocytic vesicles. Then these cells are embedded in biopolymeric hydrogels, which are used to verify that the stability of photoacoustic conversion of the particles is retained in their inclusion into cellular vehicles. We are confident that these results may provide new inspiration for the development of novel strategies to deliver plasmonic particles to tumors.

We show the preparation and address the feasibility of cellular vehicles containing gold nanorods for the photoacoustic imaging of cancer.

Preparazione e fotoacustico Analisi dei veicoli cellulari contenenti oro Nanorods

Gold nanorods are attractive for a range of biomedical applications, such as the photothermal ablation and the photoacoustic imaging of cancer, thanks to ...

Gold Nanoparticle Synthesis

Gold nanoparticles (Au nanoparticles) that are ~12 nm in diameter were synthesized by rapidly injecting a solution of 150 mg (0.15 mmol) of tetrachloroauric acid in 3.0 g (3.7 mmol, 3.6 mL) of oleylamine (technical grade) and 3.0 mL of toluene into a boiling solution of 5.1 g (6.4 mmol, 8.7 mL) of oleylamine in 147 mL of toluene. While boiling and mixing the reaction solution for 2 hours, the color of the reaction mixture changed from clear, to light yellow, to light pink, and then slowly to dark red. The heat was then turned off, and the solution was allowed to gradually cool down to room temperature for 1 hour. The gold nanoparticles were then collected and separated from the solution using a centrifuge and washed three times; by vortexing and dispersing the gold nanoparticles in 10 mL portions of toluene, and then precipitating the gold nanoparticles by adding 40 mL portions of methanol and spinning them in a centrifuge. The solution was then decanted to remove any remaining byproducts and unreacted starting materials. Drying the gold nanoparticles in a vacuum environment produced a solid black pellet; which could be stored for long periods of time (up to one year) for later use, and then redissolved in organic solvents such as toluene.

A protocol for synthesizing ~12 nm diameter gold nanoparticles (Au nanoparticles) in an organic solvent is presented. The gold nanoparticles are capped with oleylamine ligands to prevent agglomeration. The gold nanoparticles are soluble in organic solvents such as toluene.

Sintesi della nanoparticella d'oro

Gold nanoparticles (Au nanoparticles) that are ~12 nm in diameter were synthesized by rapidly injecting a solution of 150 mg (0.15 mmol) of ...

Synthesis of Functionalized 10-nm Polymer-coated Gold Particles for Endothelium Targeting and Drug Delivery

Gold nanoparticles (AuNPs) have been used extensively in medical research due to their size, biocompatibility, and modifiable surface. Specific targeting and drug delivery are some of the applications of these AuNPs, but endothelial extracellular matrices&#39; defensive properties hamper particle uptake. To address this issue, we describe a synthesis method for ultrasmall gold nanoparticles to improve vascular delivery, with customizable functional groups and polymer lengths for further adjustments. The protocol yields 2.5 nm AuNPs that are capped with tetrakis(hydroxymethyl)phosphonium chloride (THPC). The replacement of THPC with hetero-functional polyethylene glycol (PEG) on the surface of the AuNP increases the hydrodynamic radius to 10.5 nm while providing various functional groups on the surface. The last part of the protocol includes an optional addition of a fluorophore to allow the AuNPs to be visualized under fluorescence to track nanoparticle uptake. Dialysis and lyophilization were used to purify and isolate the AuNPs. These fluorescent nanoparticles can be visualized in both in vitro and in vivo experiments due to the biocompatible PEG coating and fluorescent probes. Additionally, the size range of these nanoparticles render them an ideal candidate for probing the glycocalyx without disrupting normal vasculature function, which may lead to improved delivery and therapeutics.

We describe a method of synthesizing biocompatible 10-nm gold nanoparticles, functionalized by coating poly-ethylene glycol onto the surface. These particles can be used in vitro and in vivo for delivering therapeutics to nanoscale cellular and extracellular spaces that are difficult to access with conventional nanoparticle sizes.

Sintesi di particelle d'oro rivestite di polimeri 10-nm funzionalizzate per il Targeting di endotelio e Drug Delivery

Gold nanoparticles (AuNPs) have been used extensively in medical research due to their size, biocompatibility, and modifiable surface. Specific targeting ...

Idrochinone Based Sintesi di oro Nanorods

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