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. Síntese de ouro nanobastões Nota: Use água altamente purificada por toda parte. <ol><li> Preparação das sementes de ouro <ol><li> Dissolve-se 364,4 mg de brometo de hexadeciltrimetilamónio (CTAB) em 5 ml de água, sob ultra-sons a 40 ° C até a solução se tornar clara. Deixar a solução de CTAB arrefecer até à temperatura ambiente. </li><li> Separadamente, preparar 5 ml de ácido tetracloroáurico (HAuCl 4) em água (0,5 mM). </li><li> Adicionar a solução de HAuCl 4 para a solução de CTAB sob agitação magnética vigorosa, mantendo a temperatura constante a 27 ° C. </li><li> Preparar 600 ul de boro-hidreto de sódio (NaBH4) em solução de água (10 mM) a 4 ° C. Adicionar esta solução à mistura, sob agitação vigorosa. Verifique se a cor da solução muda imediatamente de amarelo para marrom. </li><li> Agita-se a suspensão durante 20 min antes da utilização. Conserve a suspensão sementes por não mais de 24 horas a tempera quartotura. </li><li> Verificar as dimensões das sementes usando um espectrofotómetro de UV-Vis. Certifique-se de que as sementes estão suficientemente pequeno (cerca de 2 nm) para ser utilizado na preparação de nanorods ouro por espectroscopia de UV-visível. Nota: Espectro deve ser semelhante ao que é apresentado na Figura 1 sementes maiores, identificados pela presença de um pico em torno de 505-520 nm plasmónico não devem ser usados ​​porque são susceptíveis de produzir nanopartículas esféricas.. </li></ol></li><li> Preparação da &quot;solução de crescimento&quot; de nanobastões de ouro. <ol><li> Dissolve-se 182,2 mg de CTAB em conjunto com 22 mg de hidroquinona em 5 ml de água a 40 ° C, utilizando ultra-sons. Arrefecer a solução para 27 ° C. </li><li> Preparar 200 ul de nitrato de prata mM 4 (AgNO 3). </li><li> Separadamente, preparar 5 ml de uma solução 1 mM de ácido tetracloroáurico (HAuCl 4). </li><li> Primeiro adicione a solução de nitrato de prata preparada no passo 1.2.2. Em seguida, adicione o HAuCl 4 solução preparada no passo 1.2.3 para a solução de CTAB e hidroquinona preparado no passo 1.2.1, sob agitação magnética. </li><li> Imediatamente depois, adicionar sob agitação magnética de 12 ul da suspensão de sementes previamente preparado de acordo com o protocolo relatado no passo 1.1 e deixar que o início da reacção. Verifique se a suspensão muda de cor em cerca de 30 min. </li><li> Controlar a formação dos nanobastões, verificando o espectro UV-visível da suspensão, como descrito no capítulo 4, a cada 5 minutos. Prosseguir até que o espectro é estável. Para permitir a formação completa dos nanorods, deixar a suspensão sob agitação durante mais 30 minutos (Figura 2). </li><li> Dividir a suspensão em tubos (1 ml de suspensão para cada tubo) e centrifugar a 10000 xg durante 10 min. nanorods ouro formar um precipitado escuro no fundo do tubo. </li><li> Ressuspender o precipitado de cada tubo em 1 ml de água. Misture o conteúdo dos tubos e armazenar o suspension de nanobastões de ouro à temperatura ambiente. </li><li> Caracterizar os nanobastões obtidas por microscopia eletrônica de espectroscopia e transmissão UV-visível como descrito no ponto 4 (Figura 3). </li></ol></li></ol> 2. Ajuste a relação de aspecto de nanobastões pela variação da concentração de íons Ag + <ol><li> Prepara-se uma solução de nitrato de prata com uma concentração de 4 mM, dissolvendo 3,4 mg de AgNO3 em 5 ml de água. </li><li> Prepara-se três frascos diferentes a solução com CTAB e hidroquinona como descrito na secção 1.2.1, respectivamente e adicionar 100 ul, 150 ul e 200 ul de solução de nitrato de prata. </li><li> Adicione o 4 solução HAuCl acordo com preparada para o passo 1.2.3 e prosseguir com a preparação de nanobastões de ouro, como descrito a partir do ponto 1.2.5. </li><li> Caracterizar os nanobastões obtidos por espectroscopia UV-visível e microscopia eletrônica de transmissão. Tubos de ensaio com menores quantidades de Ag + resultar em nanorods mais curtos (proporção de 2 e 2,2, respectivamente) (Figura 4). </li></ol> 3. Ajustando a Relação de Aspecto da nanobastões pela variação da concentração de CTAB <ol><li> Preparar diferentes lotes de ouro nanorods com diferentes concentrações de CTAB na &quot;solução de crescimento&quot;. Use concentrações de 10 a 100 mm para produzir nanobastões de ouro com tamanho diferente e relação de aspecto. As concentrações de CTAB utilizados em cada experiência estão resumidos na Tabela 1 com a correspondente quantidade de miligramas utilizado. Dissolve-se as diferentes quantidades de CTAB sempre com 22 mg de hidroquinona em 5 ml de água. </li><li> Adicionar 200 ul de solução de nitrato de prata (preparado de acordo com o passo 1.2.2) e 5 ml de HAuCl 4 solução de (preparada de acordo como descrito no passo 1.2.3) em cada frasco, sob agitação magnética. </li><li> Adicionar 12 ul de suspensão de sementes e observar a mudança de cor da mistura final. </li><li> Parea agitação quando a cor da suspensão e o espectro de UV-visível são estabilizadas; o tempo de reacção depende da concentração de CTAB na solução de crescimento. </li><li> Centrifugar a 10000 xg durante 10 min e ressuspender em água. </li><li> Caracterizar os nanobastões obtidos por espectroscopia UV-visível e microscopia eletrônica de transmissão. Uma menor concentração de CTAB irá resultar em nanorods mais curtos, enquanto uma concentração mais elevada dará mais longos, mas maiores nanorods. Por contrário a proporção dos nanorods aspecto será maior na gama de cerca de 40-50 mM e irá diminuir tanto a concentrações mais baixas e mais altas (Figura 5 e Figura 6). </li></ol> 4. Caracterização de ouro nanobastões <ol><li> Espectroscopia de UV-visível <ol><li> Dilui-se 100 ul de solução nanorods com 400 ul de água num micro-cuvete de plástico e adquirir o espectro de absorção no UV-visível (comprimento de onda entre 400 e 840 nm)de acordo com o protocolo do fabricante. </li><li> Recolhe espectros de UV-visível (comprimento de onda entre 400 e 840 nm) da solução de crescimento a cada 5 minutos, a fim de estudar a cinética da reacção. </li></ol></li><li> Microscopia Eletrônica de Transmissão (TEM) <ol><li> Recolhe imagens TEM de cada amostra de nanorods, para a medição do tamanho e da proporção de aspecto nanorods obtidos. Preparar as amostras colocando uma gota de suspensão (4 uL) para uma ultra-finas grelhas de cobre de malha 200 revestidas com Formvar e deixar secar ao ar a 4 ° C. Analisar a amostra a MET usando uma voltagem de aceleração de 200 kV, de acordo com o protocolo do fabricante. </li></ol></li></ol>

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The authors have nothing to disclose.

O protocolo aqui apresentado é aplicável a hidroquinona, uma molécula aromática caracterizada por um fraco potencial de redução, para produzir nanorods ouro. Existem duas principais vantagens da presente protocolo para a via sintética mais vulgarmente empregue com base na utilização de ácido ascórbico: a primeira é que a hidroquinona é capaz de reduzir quase quantitativamente os iões de ouro que permitam a produção de uma maior quantidade de nanorods ouro 11 A. Esta última é dada pelo facto ...

As nanopartículas de ouro (AuNPs) são um dos mais difundidos e nanoestruturas promissores para ser utilizada em aplicações biomédicas. A sua utilização é essencial em muitas ponto-de-cuidado diagnóstico in vitro produtos 1 Eles têm sido propostos como uma ferramenta eficaz para um certo número de outras aplicações diferentes:., Como um agente de contraste em estudos de imagem, 2 como um sistema de entrega de droga 3 e quanto drogas para a termoterapia induzida pela luz (ou terapia fototérmico). 4 o grande potencial de AuNPs conduziu, nos últimos vinte anos, intensa investigação sobre o desenvolvimento de nova síntese que é capaz de aumentar o controlo sobre o tamanho e a forma obtida. 5 Isto é porque diferentes tipos de AuNPs são, de facto, mais adequado do que outros para aplicações específicas. Entre os diferentes nanoestruturas de ouro, nanorods ouro (AuNRs) têm emergido como um dos sistemas mais interessantes. AuNRs são caracterizados por dois Plasmopicos nic associados com a oscilação de electrões ao longo do eixo longitudinal e os eixos transversais, respectivamente. 6 É particularmente importante que a posição do pico longitudinal mais intenso pode ser sintonizado precisamente entre 620 e 800 nm, dependendo da relação das hastes aspecto . Esta região corresponde à janela biológica, 7 em que os tecidos humanos quase não absorvem a luz, permitindo o desenvolvimento de um número de aplicações fotónicas in vivo envolvendo AuNPs. Apesar de um grande interesse por este tipo de nanoestruturas, os protocolos de síntese para a preparação de AuNRs sofrem de várias limitações. Na maioria dos casos, nanorods são preparados de acordo com um método de dois passos desenvolvida por Sau e colegas de trabalho. 8 no seu protocolo, nanorods são sintetizados por redução de iões de ouro, utilizando o ácido ascórbico em presença de sementes de ouro pré-formados, os iões de prata e uma grande quantidade de brometo de hexadecil-trimetilamónio (CTAB), ACsurfactante linear ationic. O inconveniente deste protocolo é de que o rendimento de redução dos iões de ouro é relativamente baixa (cerca de 20%) 9 e que uma elevada quantidade de CTAB, um reagente dispendioso que é responsável por mais de metade do custo total para os reagentes na síntese, é preciso. O desenvolvimento de uma via de síntese nova e mais eficaz é daí considerada como sendo uma importante necessidade, permitindo a difusão de abordagens com base em biomédicas AuNRs. Na primeira parte do presente trabalho, apresentamos um protocolo otimizado para a preparação de AuNR tendo uma proporção de cerca de três aspectos. A síntese é baseada no uso de hidroquinona como um agente redutor suave e que permite a preparação de AuNR com uma redução de quase quantitativa de iões de ouro, fazendo uso de uma quantidade reduzida de CTAB. 10 Este protocolo para a preparação dos AuNRs baseia numa abordagem em duas fases em que as sementes de ouro são usados ​​em uma &quot;Sol crescimentoution &quot;. Na segunda parte, vamos mostrar como finamente ajustar o tamanho e formato do AuNR obtido de duas maneiras. A primeira forma, semelhante ao protocolo padrão à base de ácido ascórbico, é para variar a quantidade de iões de prata presentes na &quot;solução de crescimento&quot;. A segunda maneira baseia-se na variação da quantidade de CTAB que pode ser reduzida até uma concentração de 10 mM (perto da concentração micelar crítica relatado pelo fornecedor) para se obter nanorods curtas bem 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.

Os espectros de UV visível das sementes de ouro pode ser visto na Figura 1. Os espectros de UV visível adquiridas em tempos diferentes após a injecção das sementes de ouro são apresentados na Figura 2. Imagens Os espectros de UV visível e de microscopia electrónica de transmissão (TEM) das nanorods ouro obtidos são mostrados na Figura 3. microscópica de UV visível e os espectros de transmissão de electrão (TEM) de imagens n...

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

Hydroquinone Based Synthesis of Gold Nanorods

Este documento descreve um protocolo para a síntese de ouro nanorods, baseado no uso de hidroquinona como agente de redução, mais os diferentes mecanismos para controlar o tamanho e a relação de aspecto.

Hidroquinona baseada Síntese de ouro 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 San Sebastian

Research

JoVE Journal

Chemistry

13.6K visualizações.  Fondazione Don Carlo Gnocchi ONLUS (Don Carlo Gnocchi Foundation).  Este documento descreve um protocolo para a síntese de ouro nanorods, baseado no uso de hidroquinona como agente de redução, mais os diferentes mecanismos para controlar o tamanho e a relação de aspecto. 

Vídeo: 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.

Dirigido modelo de síntese de nanotubos de Ouro plasmônicos com Absorbância IR Tunable

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

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.

Síntese Nanostar ouro com um método de crescimento de sementes de Prata 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 ...

Bioengenharia

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.

Síntese, caracterização e funcionalização de híbrida UA / CDS e Au / ZnS Núcleo / 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.

Um método simples para o tamanho Síntese controlada de estáveis ​​Oligoméricas Clusters de nanopartículas em condições ambientais

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 Síntese de Nanopartículas de Ouro sem agregação no espaço Interlayer de Layered titanato filmes transparentes

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

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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.

Síntese e caracterização de nanopartículas de ouro Anfífilos

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.

Montagem de Nanobastões de Ouro em Metamoléculas Plasmônicas Quirais Usando Modelos de Origami de 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.

Preparação e Fotoacústica Análise de Veículos celulares contendo ouro nanobastões

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.

Síntese de Nanopartículas de Ouro

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.

Síntese de funcionalizados 10 nm polímero-revestida com partículas de ouro para o direcionamento do endotélio e entrega da droga

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

Hidroquinona baseada Síntese de ouro Nanorods

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