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. Síntesis de oro Nanorods Nota: Use agua altamente purificada en todas partes. <ol><li> Preparación de las semillas de oro <ol><li> Disolver 364.4 mg de bromuro de hexadeciltrimetilamonio (CTAB) en 5 ml de agua, bajo ultrasonidos a 40 ° C hasta que la solución se vuelve transparente. Deje que la solución de CTAB se enfríe a temperatura ambiente. </li><li> Por separado, preparar 5 ml de ácido tetracloroáurico (HAuCl4) en agua (0,5 mM). </li><li> Añadir la solución de HAuCl4 a la solución de CTAB en agitación magnética vigorosa, manteniendo la temperatura constante a 27 ° C. </li><li> Preparar 600 l de borohidruro de sodio (NaBH4) solución en agua (10 mM) a 4 ° C. Añadir esta solución a la mezcla con agitación vigorosa. Compruebe si el color de la solución cambia inmediatamente de amarillo a marrón. </li><li> Se agita la suspensión durante 20 minutos antes de su uso. Guarde la suspensión semillas durante no más de 24 horas a tempera ambientetura. </li><li> Comprobar las dimensiones de las semillas usando un espectrofotómetro UV-Vis. Asegúrese de que las semillas son lo suficientemente pequeño (alrededor de 2 nm) que se utilizarán en la preparación de nanorods oro por espectroscopia UV-visible. Nota: Spectrum debe ser similar a lo que se informa en la Figura 1 las semillas más grandes identificados por la presencia de un pico alrededor de 505 a 520 nm plasmónica no deben ser utilizados, ya que son propensos a producir nanopartículas esféricas.. </li></ol></li><li> Preparación de la &quot;solución de crecimiento&quot; de oro nanorods. <ol><li> Disolver 182,2 mg CTAB junto con 22 mg de hidroquinona en 5 ml de agua a 40 ° C usando ultrasonidos. Enfriar la solución a 27 ° C. </li><li> Preparar 200 l de nitrato de plata, 4 mM de solución (AgNO3). </li><li> Por separado, preparar 5 ml de solución 1 mM de ácido tetracloroáurico (HAuCl4). </li><li> Primero se debe agregar la solución de nitrato de plata preparada en el paso 1.2.2. A continuación, añadir el Haucl solución de 4 preparado en la etapa 1.2.3 a la solución de CTAB y la hidroquinona preparado en la etapa 1.2.1 bajo agitación magnética. </li><li> Inmediatamente después, añadir en agitación magnética de 12 l de la suspensión semillas previamente preparada de acuerdo con el protocolo informaron en el paso 1.1 y dejar que el comienzo de la reacción. Compruebe si la suspensión cambia de color en aproximadamente 30 minutos. </li><li> Controlar la formación de los nanobastones marcando el espectro UV-visible de la suspensión, tal como se describe en la sección 4, cada 5 min. Continúe hasta que el espectro es estable. Para permitir la formación completa de los nanobastones, dejar la suspensión en agitación durante otros 30 minutos (Figura 2). </li><li> Dividir la suspensión en tubos (1 ml de suspensión de cada tubo) y se centrifuga a 10.000 xg durante 10 min. nanorods oro forman un precipitado oscuro en la parte inferior del tubo. </li><li> Resuspender el precipitado de cada tubo en 1 ml de agua. Mezclar el contenido de los tubos y almacenar la suspensión de oro nanorods a temperatura ambiente. </li><li> Caracterizar los nanobastones obtenidas por microscopía electrónica de transmisión y la espectroscopia UV-visible como se describe en la sección 4 (Figura 3). </li></ol></li></ol> 2. Ajuste de la Relación de Aspecto de Nanorods variando la concentración de iones Ag + <ol><li> Preparar una solución de nitrato de plata con una concentración de 4 mM, la disolución de 3,4 mg AgNO 3 en 5 ml de agua. </li><li> Preparar en tres diferentes viales de la solución con CTAB e hidroquinona como se describe en la sección 1.2.1, respectivamente, y añadir 100 l, 150 l ó 200 l de solución de nitrato de plata. </li><li> Añadir la HAuCl4 solución preparada según la etapa 1.2.3 y proceder con la preparación de oro nanorods como se describe desde el punto 1.2.5. </li><li> Caracterizar los nanobastones obtenidos por espectroscopia UV-visible y microscopía electrónica de transmisión. Viales con menores cantidades de Ag + se reresultar en nanobastones más cortos (relación de aspecto de 2 y 2,2, respectivamente) (Figura 4). </li></ol> 3. Ajuste de la Relación de Aspecto de Nanorods variando la concentración de CTAB <ol><li> Preparar diferentes lotes de oro nanorods con diferentes concentraciones de CTAB en la &quot;solución de crecimiento&quot;. Use concentraciones de 10 mM a 100 mM para producir nanorods de oro que tienen diferente tamaño y relación de aspecto. Las concentraciones de CTAB utilizados en cada experimento se resumen en la Tabla 1 con la correspondiente cantidad de miligramos utilizado. Disolver las diferentes cantidades de CTAB siempre con 22 mg de hidroquinona en 5 ml de agua. </li><li> Añadir 200 l de solución de nitrato de plata (preparado de acuerdo con el paso 1.2.2) y 5 ml de solución de HAuCl4 (preparado según la forma descrita en el paso 1.2.3) en cada vial con agitación magnética. </li><li> Añadir 12 l de suspensión de semillas y observar el cambio de color de la mezcla final. </li><li> Detenerla agitación cuando el color de la suspensión y el espectro de UV-visible se estabilizan; el tiempo de reacción depende de la concentración de CTAB en la solución de crecimiento. </li><li> Centrifugar a 10.000 xg durante 10 min y se resuspenden en agua. </li><li> Caracterizar los nanobastones obtenidos por espectroscopia UV-visible y microscopía electrónica de transmisión. A menor concentración de CTAB resultará en nanorods más cortos, mientras que una concentración más alta dará nanorods más largos pero más grandes. En contra de la relación de aspecto de los nanorods será más alto en el rango de alrededor de 40 a 50 mM y disminuirá tanto a concentraciones más bajas y más altas (Figura 5 y Figura 6). </li></ol> 4. Caracterización de oro Nanorods <ol><li> Espectroscopía UV-visible <ol><li> Diluir 100 l de solución de nanorods con 400 l de agua en un micro-cubeta de plástico y adquirir el espectro de absorción UV-visible (longitud de onda entre 400 y 840 nm)de acuerdo con el protocolo del fabricante. </li><li> Recoger los espectros UV-visible (longitud de onda entre 400 y 840 nm) de la solución de crecimiento cada 5 min con el fin de estudiar la cinética de la reacción. </li></ol></li><li> Microscopía Electrónica de Transmisión (TEM) <ol><li> Recoger imágenes TEM de cada muestra de nanorods, para la medición del tamaño y de la relación de aspecto de los nanorods obtenidos. Preparar las muestras colocando una gota de suspensión (4 l) en un ultra-delgadas rejillas de cobre de malla 200 Formvar recubierto con y dejar secar al aire a 4 ° C. Analizar la muestra a TEM usando un voltaje de aceleración de 200 kV de acuerdo con el protocolo del fabricante. </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.

El protocolo que se presenta aquí se aplica hidroquinona, una molécula aromática caracterizado por un potencial de reducción débil, para producir nanorods de oro. Hay dos ventajas principales de la presente protocolo hacia la ruta sintética más comúnmente empleado basado en el uso de ácido ascórbico: la primera es que la hidroquinona es capaz de reducir casi cuantitativamente los iones de oro que permiten la producción de una mayor cantidad de nanorods oro 11 La. este último es dada por el hecho d...

Las nanopartículas de oro (AuNPs) son una de las nanoestructuras más extendidas y prometedores para ser utilizados en aplicaciones biomédicas. Su uso es esencial en muchas de punto de cuidado de diagnóstico in vitro productos 1 Ellos se han propuesto como una herramienta eficaz para un número de otras aplicaciones diferentes:. Como agente de contraste en los estudios de imagen, 2 como un sistema de suministro de medicamento 3 y como medicamentos para la termoterapia inducida por la luz (o la terapia fototérmica). 4 el gran potencial de AuNPs ha conducido, en los últimos veinte años, una intensa investigación sobre el desarrollo de la nueva síntesis que es capaz de aumentar el control sobre el tamaño y la forma obtenida. 5 esto se debe a los diferentes tipos de AuNPs son de hecho más adecuados que otros para aplicaciones específicas. Entre las diferentes nanoestructuras de oro, oro nanorods (AuNRs) han surgido como uno de los sistemas más interesantes. AuNRs se caracterizan por dos plasmopicos nic asociados con la oscilación de los electrones a lo largo de la dirección longitudinal y los ejes transversales, respectivamente. 6, es especialmente importante que la posición del pico longitudinal más intensa se ​​puede ajustar precisamente entre 620 y 800 nm, dependiendo de la relación de aspecto de las barras de . Esta región coincide con la ventana biológica, 7, donde los tejidos humanos casi no absorben la luz, lo que permite el desarrollo de una serie de aplicaciones fotónicas en vivo que implica AuNPs. A pesar de un gran interés en este tipo de nanoestructuras, los protocolos sintéticos para la preparación de AuNRs sufren de varias limitaciones. En la mayoría de los casos, nanorods se preparan de acuerdo con un método de dos pasos desarrollado por Sau y compañeros de trabajo. 8 En su protocolo, nanorods se sintetizan mediante la reducción de iones de oro utilizando ácido ascórbico en presencia de semillas de oro preformados, iones de plata y una cantidad grande de bromuro de hexadecil trimetilamonio (CTAB), acsurfactante lineal ationic. El inconveniente de este protocolo es que el rendimiento de reducción de iones de oro es relativamente baja (alrededor del 20%) 9 y que una gran cantidad de CTAB, un reactivo caro que da cuenta de más de la mitad del costo total de los reactivos en la síntesis, se necesita. El desarrollo de una ruta sintética nuevo y más eficiente es desde allí considera que es una necesidad importante, lo que permite la difusión de enfoques biomédicos a base de AuNRs. En la primera parte de este trabajo, presentamos un protocolo optimizado para la preparación de AuNR que tiene una relación de aspecto de aproximadamente tres. La síntesis se basa en el uso de hidroquinona como un agente reductor suave y permite la preparación de AuNR con una reducción casi cuantitativa de iones de oro, haciendo uso de una cantidad reducida de CTAB. 10 Este protocolo para la preparación de los AuNRs se basa en un enfoque de dos etapas, donde se utilizan semillas de oro en un &quot;sol de crecimientolución &quot;. En la segunda parte, nos muestran cómo sintonizar finamente el tamaño y la relación de aspecto de la AuNR obtenida de dos maneras. La primera manera, similar al protocolo estándar basado en el ácido ascórbico, es variar la cantidad de iones de plata presentes en la &quot;solución crecimiento&quot;. La segunda forma en que se basa en la variación de la cantidad de CTAB que puede ser reducido a una concentración de 10 mM (cerca de la concentración micelar crítica informado por el proveedor) para obtener nanorods cortos bien definidos.

<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 espectros visible de las semillas de oro se puede ver en la Figura 1. UV espectros visible adquirido en diferentes momentos después de la inyección de las semillas de oro se presenta en la Figura 2. Imágenes UV espectros visible y microscópico electrónico de transmisión (TEM) de los nanorods oro obtenidos se muestra en la Figura 3. imágenes microscópicas UV visible espectros y la transmisión de electrones (TEM) de nanorods or...

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

Hydroquinone Based Synthesis of Gold Nanorods

Este documento describe un protocolo para la síntesis de nanorods de oro, basado en el uso de hidroquinona como agente reductor, además de los diferentes mecanismos para el control de su tamaño y la relación de aspecto.

Hidroquinona basado Síntesis de 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 vistas.  Fondazione Don Carlo Gnocchi ONLUS (Don Carlo Gnocchi Foundation).  Este documento describe un protocolo para la síntesis de nanorods de oro, basado en el uso de hidroquinona como agente reductor, además de los diferentes mecanismos para el control de su tamaño y la relación de aspecto. 

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.

Plantilla Dirigida Síntesis de nanotubos de oro plasmónicos con Tunable absorbancia IR

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

Investigación

Química

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.

Síntesis y rendimiento catalítico de Oro intercalados en las Murallas de sílice mesoporoso

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 método simple para la síntesis controlada de tamaño estables Clusters oligómeros de nanopartículas de oro bajo condiciones ambientales

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.

Fotoquímico oxidativo Crecimiento de iridio nanopartículas de óxido de 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.

Síntesis y evaluación de un inhibidor de la absorción de calcio mitocondrial basado en 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.

Mejora de señal rápida Nanoprobe por síntesis de nanopartículas de 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.

Síntesis de nanopartículas bimetálicas Pt/Sn-basados en líquidos iónicos

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.

Síntesis y caracterización de nanopartículas de oro anfifílicas

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.

Asamblea de nanobarras de oro en Metamolecules plasmónica quirales mediante plantillas de Origami de ADN

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.

Fotodeposición de Pd en Colloidal Au Nanorods por Surface Plasmon Excitation

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