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><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 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

Universidad de Cartagena UDEC

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

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.

Síntesis de oro Nanostar con un método de la Simiente de Plata crecimiento mediada por

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 ...

Bioingeniería

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.

Síntesis, caracterización y funcionalización de híbridos Au / CdS y Au / ZnS Core / Shell nanopartículas

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 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 ...

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 Síntesis de nanopartículas de oro sin agregación en el espacio entre capas de Capas de titanato películas transparentes

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

Ingeniería

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 ...

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.

Análisis preparación y fotoacústica de Vehículos celulares que contienen 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.

Síntesis de nanopartículas de 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.

Síntesis de funcionalizados 10 nm recubierto de polímero partículas de oro para apuntar el endotelio y el suministro de medicamentos

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