Os autores agradecem o Departamento de Química e da Faculdade de Pós-Graduação da Universidade Estadual do Missouri para o seu apoio a este projeto. Reconhecemos também o Electron Microscopy Laboratório do Laboratório Nacional Frederick para Pesquisa do Câncer para o uso de seu microscópio eletrônico de transmissão e redes revestidas de carbono.

1. Síntese de fosfeto de índio / Zinc Sulfide (INP / ZnS) Quantum Dots <ol><li> Síntese de fosfeto de índio (InP) Quantum Dot Cores <ol><li> Caber um fundo redondo de 100 ml, 3-neck, garrafa com um condensador de 12 polegadas. Adicionar 30 ml de oleilamina (OLA), cloreto de 0,398 g de índio (III) (incl 3), (II), cloreto de 0,245 g de zinco (ZnCl2) e agita-se durante a evacuação, à TA utilizando um vácuo durante 1 hora. A solução deve aparecer incolor com um precipitado branco. </li><li> Usando uma manta de aquecimento, com um termopar e controlador de temperatura proporcional-integral-derivativo (PID), aumentar a temperatura da solução a 120 ° C. Evacuar a solução sob vácuo durante 20 min para remover as impurezas de baixo ponto de ebulição que podem afectar o crescimento do núcleo. Nota: Embora seja possível utilizar um banho de areia e termómetro, usando uma manta de aquecimento e PID aumenta a uniformidade e a reprodutibilidade dos produtos da reacção. </li><li> Sob um gás inerte (por exemplo,, N2), refluxo a solução e aumentar a temperatura para 220 ° C durante 15 min. O InCl3 e ZnCl2 dissolver completamente, resultando numa solução amarelo pálida. Permitir que a temperatura estabilize, durante 10 min. </li><li> Purgar a, 3 ml seringa de plástico descartável e 4 polegadas, 22 G agulha com gás nitrogênio. Usando a seringa, para entregar rapidamente 0,5 ml de tris (dimetilamino) fosfina (TDMAP) à solução de InCl3. A temperatura da solução diminui ligeiramente e retorna a 220 ° C. A solução muda de transparente, amarelo pálido a opaco, preto. </li><li> Após 9,5 min, remover o balão de reacção a partir da manta de aquecimento até que a temperatura diminui abaixo de 200 ° C. Para proteger a integridade dos núcleos de InP, seguir diretamente para a etapa de revestimento de ZnS em 1.2.1. </li></ol></li><li> Síntese de Sulfeto de zinco Conchas (ZnS) quantum dot <ol><li> Colocar o balão de reacção a partir do passo 1.1.5 em uma manta de aquecimento e estabilizar o temperatura a 200 ° C. Adiciona-se lentamente 3,58 g dodecanotiol (DDT) ao longo de 15 seg para a solução contendo InP QDs. Permitir que a solução reagir durante 1 h. Nota: a espessura da casca de ZnS pode ser variado aumentando ou diminuindo a quantidade de estearato de zinco adicionado no passo 1.2.4. Alterando a quantidade de ZnCl2 ou dodecanotiol em passos 1.1.1 e 1.2.1 podem ter impacto significativo na qualidade de QDs alterando a cinética da reacção. <ol><li> Depois, remover o balão de reacção a partir da manta de aquecimento e deixar a solução arrefecer até cerca de 60 ° C. </li></ol></li><li> Uma vez que a solução de InP / ZnS atinge ~ 60 ° C, adicionar 10 ml de hexanos e transferir toda a solução de cerca de 45 ml para um tubo de centrífuga de polipropileno de 50 ml. Centrifugar a amostra (3000 xg durante 10 min) para remover os precursores sólidos que não reagiram. </li><li> Transferir cuidadosamente o sobrenadante para um frasco de 250 ml de centrífuga de polipropileno, adicionar 200 ml de acetona, e a solução de centrífuga (3.000 xg durante 10 min) para precipitar QDs InP / ZnS. Este volume também pode ser dividido uniformemente em quatro tubos de 50 ml para centrifugação se uma centrífuga com as necessárias rotor / acessórios não está disponível. Decantar o sobrenadante e o sedimento secar QD cuidadosamente com azoto gasoso para remover a acetona. </li><li> Volte a suspender as QDs em 20 ml OLA usando sonicação, transferir para um fundo redondo de 50 ml, 3-pescoço, frasco contendo 0,474 g estearato de zinco, e mexa. Evacuar a solução sob vácuo durante 20 min à temperatura ambiente. </li><li> Sob atmosfera de azoto, aumentar a temperatura para 180 ° C e deixar a reacção prosseguir durante 3 horas. Embora não existam alterações visuais perceptíveis à solução de reacção que ocorrem durante esta reacção, a adição de estearato de zinco aumenta a espessura da casca de ZnS, aumentando, assim, QY, melhorando a passivação de superfície 12. QDs. Uma vez que a reacção está completa, remover o balão da manta de aquecimento e deixar a solução arrefecer até cerca de 60 ° C. </li><li> Uma vez que a solução que InP / ZnSno ~ atinge 60 ° C, adicionar 20 ml de hexanos e transferir para um tubo de centrífuga de polipropileno de 50 ml. Centrifugar a amostra (3000 xg durante 10 min) para remover o estearato de zinco que não reagiu. </li><li> Transferir cuidadosamente o sobrenadante para um frasco de centrífuga de polipropileno de 250 ml, adicionar 200 ml de acetona, e centrifuga-se a solução (3000 xg durante 10 min) para precipitar InP / ZnS QDs. Cuidadosamente decantar o sobrenadante e completamente seco com azoto gasoso para remover a acetona. </li><li> Dissolve-se o sedimento InP / ZnS QD em 30 ml de hexano. Vortex e sonicar a solução rapidamente para assegurar a dispersão completa. </li><li> Repita os passos de purificação 1.2.6-1.2.8 mais duas vezes para assegurar a remoção completa do excesso de ligandos orgânicos. As interacções entre o polímero anfifílico e o QD na etapa 1.2 pode ser comprometida, na presença de ligandos em excesso. </li><li> Com cálculos detalhado por Xie, et al. 16, determinar o tamanho ea concentração dos QDs InP / ZnS sintetizados usando UV-Vis. <br/&gt; Nota: A característica espectral importante para esta análise é o ombro do pico de absorção. O valor do comprimento de onda e da absorvância máxima deste ombro é utilizada para calcular o tamanho e a concentração dos QDs, respectivamente. Esta reacção produz tipicamente cerca de 5 umol de QDs com um pico de emissão a 600 nm. Para sintetizar QDs de cores diferentes, a duração e / ou a temperatura da reacção pode ser alterada. Um maior tempo de reacção e / ou temperatura mais elevada dos resultados solução num pico de emissão vermelho-deslocado. Por exemplo, aumentando a temperatura da reacção a 240 ° C e mantendo o tempo de reacção de 10 min irá resultar em QDs com um pico de 680 nm no máximo as emissões. Da mesma forma, reduzindo o tempo de reacção de 2 min e dobrando o cloreto de zinco utilizado irá resultar em QDs com um pico de emissão máxima 470 nm. Estes QDs InP / ZnS são estáveis ​​durante pelo menos um mês a 4 ° C no escuro sob atmosfera de gás inerte. </li></ol></li></ol> 2. águaSolubilização de InP / ZnS Quantum Dots Usando um polímero anfifílico <ol><li> A solubilização de água <ol><li> Usando os QDs InP / ZnS do passo 1.2.10, diluir uma parte dos QDs com hexanos para se obter 1 ml de 1 uM QDs. <ol><li> Num tubo de centrífuga, transferir 0,25 ml de InP / ZnS QDs em cada tubo. Adicionar 1 ml de acetona ou metanol para o tubo de centrífuga e centrifuga-se (3000 xg durante 10 min). remover cuidadosamente o sobrenadante e dissolve-se cada um precipitado em 1 ml de tetra-hidrofurano (THF). </li><li> Transfira os QDs InP / ZnS dissolvidos em THF em um frasco de 100 ml de fundo redondo e diluir com 16 ml THF. Para reduzir o número de agregados em solução, sonicar as QDs durante 5-10 min. </li></ol></li><li> Dissolve-se 30 mg de poli (maleico alt andhydride- -1-octadeceno), 3- (dimetilamino) -1-propilamina (PMAL-d) em 10 ml de água de grau molecular. Banho-maria de ultra-sons ou agitação suave até a solução estar translúcida é suficiente para dissolver completamente o polímero. outilização de vortex ou agitação vigorosa pode produzir muitas bolhas, o que dificulta a interacção do polímero com o QD. Adicionar a solução de polímero de 10 ml para os 100 ml balão de fundo redondo contendo InP / ZnS QDs em THF. </li><li> Evapora-se a solução de THF de QD / polímero utilizando um evaporador rotativo. Colocar o balão num banho de gelo enquanto evaporação para facilitar a interacção entre o polímero e QD. Dependendo da força do vácuo, a maioria de THF é evaporado após 10 minutos e a solução aparece turvo. <ol><li> Uma vez que a solução é evaporada para 10 ml, retirar o balão do evaporador rotativo e adicionar 30 ml de água de grau molecular. Devolver o balão no evaporador rotativo e continuar a evaporar-se a 2 ml. Esta etapa evaporação final pode levar várias horas; assegurar o banho de gelo é mantida. </li></ol></li><li> Remover os QDs InP / ZnS solúveis em água a partir do balão de fundo redondo com uma pipeta. Filtra-se a solução QD utilizando uma seringa de plástico de 3 ml ligado a um SY de nylon de 0,1 umRinge filtrar para um tubo de centrífuga de 5 ml. </li><li> Coloque as QDs em uma unidade de diálise de membrana de MWCO 20000 e diálise contra tampão de borato 0,05 M pH 8,5 para remover o excesso de polímero. (Lentamente adicionar tetraborato decahidrato de sódio 0,05 M a 0,05 M de ácido bórico, com agitação vigorosa, até que o pH é de 8,5 a tornar esta solução tampão de borato.) Utilizando um concentrador de vácuo, concentrar os QDs em tampão de borato a 1 ml. </li><li> Para o armazenamento, purgar a solução com azoto antes da selagem com Parafilm. Os QDs InP / ZnS solúveis em água são estáveis ​​durante pelo menos 4 meses a 4 ° C no escuro. </li></ol></li></ol>

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Este protocolo detalha a síntese das altamente fluorescentes QDs InP / ZnS que podem ser utilizados em muitos sistemas biológicos. Os produtos sintetizados QD aqui exibiu um único pico de emissão de fluorescência centrada a 600 nm com um FWHM de 73 nm (Figura 1), que é comparável a outras sínteses descritas anteriormente 12. O tempo de reacção e temperatura da reacção são extremamente passos cruciais, devido ao seu profundo efeito sobre a qualidade de síntese QD e repetibilidade...

A correction was made to: <a href="http://jove.unicartagenaproxy.elogim.com/video/53684/synthesis-cd-free-inpzns-quantum-dots-suitable-for-biomedical" target="_blank">Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications</a>. There was an error with an author's given name. The author's name was corrected to:
Katye M. Fichter
from:
Kathryn M. Fichter

A correction was made to: <a href="http://jove.unicartagenaproxy.elogim.com/video/53684/synthesis-cd-free-inpzns-quantum-dots-suitable-for-biomedical" target="_blank">Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications</a>.

Erratum: Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

Os pontos quânticos (QDs) são semicondutor nanocristais que exibem propriedades fluorescentes quando irradiado com luz 1. Devido ao seu pequeno tamanho (2-5 nm), que é semelhante a muitas biomoléculas grandes, e facilidade de biofunctionalization, QDs são uma ferramenta extremamente atraente para aplicações biomédicas. Eles têm encontrado utilização na rotulagem biológica, imagem única molécula-célula viva, a entrega de drogas, imagem in vivo, detecção de patógenos e rastreamento de celular, entre muitos outros usos 2-8. QDs baseada em CD foram mais comumente usados ​​em aplicações biomédicas devido à sua intensa fluorescência e larguras de pico de emissão estreitas 9. No entanto, as preocupações foram levantadas devido ao potencial de toxicidade do Cd 2+ 10 que pode ser introduzida através da degradação das nanopartículas. Recentemente, QDs baseados em InP têm sido explorados como uma alternativa para QDs baseadas em CD porque eles mantêm muitas características de fluorescênciade QDs Cd-baseado e pode ser mais biocompatível 11. QDs baseadas em CD foram encontrados para ser significativamente mais tóxica do que QDs baseados em InP em ensaios in vitro para concentrações tão baixas quanto 10 pM, após apenas 48 h 11. A cor de emissão de fluorescência de QDs é tamanho-ajustável 1. Isto é, como o tamanho das QD aumenta, a emissão de fluorescência é vermelho-deslocado. O tamanho e dimensão dispersibilidade dos produtos QD pode ser modificada alterando a temperatura, duração da reacção, ou em condições de concentração de precursor durante a reacção 12. Embora o pico de emissão de InP QDs é tipicamente mais ampla e menos intensa do que QDs baseadas em CD, InP QDs pode ser feita numa grande variedade de cores, destinadas a evitar sobreposição espectral, e são suficientemente intensa para a maioria das aplicações biomédicas 12. A síntese detalhada neste protocolo produz QDs com um pico de emissão vermelha centrado em 600 nm. Várias medidas são tomadas afsíntese ter dos núcleos QD para manter a integridade óptica dos QDs e torná-los compatíveis para aplicações biológicas. A superfície do núcleo QD deve ser protegida contra a oxidação ou defeitos superficiais, que podem causar têmpera; portanto, uma concha ZnS é revestido sobre o núcleo para produzir InP / ZnS (core / shell) qds 13. Este revestimento tem sido demonstrado para proteger o fotoluminescência do produto QD. A presença de iões de zinco, durante a síntese InP QD foi mostrado para limitar os defeitos de superfície, bem como a distribuição do tamanho de redução 12. Mesmo com a presença de Zn2 + no meio de reacção, a síntese de InZnP são altamente improvável 12. Depois do revestimento, resultantes QDs InP / ZnS são revestidos em ligandos hidrofóbicos, tais como o óxido de trioctilfosfina (TOPO) ou oleilamina 12,14. Um polímero anfifílico pode interagir com ligandos hidrófobos na superfície do QD, bem como moléculas de água em massa para conferir solubilidade em água 15. polímeros anfifílicos com carbogrupos químicos xylate pode ser utilizado como &quot;alças&quot; químicas para funcionalizar ainda mais os QDs. Este protocolo detalha a síntese e funcionalização de solúveis em água InP / ZnS QDs com emissão de fluorescência muito intenso e relativamente pequeno em tamanho dispersity. Estes QDs são potencialmente menos tóxico do que QDs CdSe / ZnS vulgarmente utilizados. Nisto, a síntese de InP / ZnS QDs fornece uma alternativa prática para QDs baseadas em CD para aplicações biomédicas.

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synthesis of cd-free inp/zns quantum dots suitable for biomedical applications

Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, quantum dots should be highly fluorescent and small/monodisperse in size. While commonly used cadmium-based quantum dots possess these qualities, they are potentially toxic due to the possible release of Cd2+ ions through nanoparticle degradation. Indium-based quantum dots, specifically InP/ZnS, have recently been explored as a viable alternative to cadmium-based quantum dots due to their relatively similar fluorescence characteristics and size. The synthesis presented here uses standard hot-injection techniques for effective nanoparticle growth; however, nanoparticle properties such as size, emission wavelength, and emission intensity can drastically change due to small changes in the reaction conditions. Therefore, reaction conditions such temperature, reaction duration, and precursor concentration should be maintained precisely to yield reproducible products. Because quantum dots are not inherently soluble in aqueous solutions, they must also undergo surface modification to impart solubility in water. In this protocol, an amphiphilic polymer is used to interact with both hydrophobic ligands on the quantum dot surface and bulk solvent water molecules. Here, a detailed protocol is provided for the synthesis of highly fluorescent InP/ZnS quantum dots that are suitable for use in biomedical applications.

Os núcleos de InP não revestidos não demonstram fluorescência visível substancial a olho nu. No entanto, InP / ZnS (core / shell) pontos quânticos parecem apresentam forte fluorescência por olho sob irradiação UV. A fluorescência de InP / ZnS QDs foi caracterizado usando espectroscopia de fluorescência. O espectro de fluorescência de QDs em hexanos (Figura 1) excitado a 533 nm demonstra um pico principal centrado a 600 nm com uma largura total a meia altura (...

Watch this Scientific Journal Video about Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications at JoVE.com

Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

In this protocol, the synthesis of Cd-free InP/ZnS quantum dots (QDs) is detailed. InP-based QDs are gaining popularity due to the toxicity of Cd2+ ions that may be released through nanoparticle degradation. After synthesis, QDs are solubilized in water using an amphiphilic polymer for use in biomedical applications.

Síntese de Cd-livre InP / ZnS Quantum Dots Indicado para aplicações biomédicas

Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, ...

synthesis-cd-free-inpzns-quantum-dots-suitable-for-biomedical

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

13.5K visualizações.  Missouri State University. In this protocol, the synthesis of Cd-free InP/ZnS quantum dots (QDs) is detailed. InP-based QDs are gaining popularity due to the toxicity of Cd2+ ions that may be released through nanoparticle degradation. After synthesis, QDs are solubilized in water using an amphiphilic polymer for use in biomedical applications.

Vídeo: Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials.

Herein the procedures for plasma enhanced chemical vapor deposition of perfluoroalkanes on microporous materials such as metal-organic frameworks to enhance their stability and hydrophobicity are described. Furthermore, breakthrough testing of milligram quantities of samples is described in detail.

Preparação de hidrofóbicos Metal-Organic Frameworks via Plasma aprimorado Chemical Vapor Deposition de perfluoroalcanos para a remoção de amônia

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high ...

Química

Synthesis of Immunotargeted Magneto-plasmonic Nanoclusters

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications including contrast enhancement in novel magnetomotive imaging modalities, simultaneous capture&#160;and detection of circulating tumor cells (CTCs),&#160;and multimodal molecular imaging combined with photothermal therapy of cancer cells. These applications have stimulated significant interest in development of protocols for synthesis of magneto-plasmonic nanoparticles with optical absorbance in the near-infrared (NIR) region and a strong magnetic moment. Here, we present a novel protocol for synthesis of such hybrid nanoparticles that is based on an oil-in-water microemulsion method. The unique feature of the protocol described herein is synthesis of magneto-plasmonic nanoparticles of various sizes from primary blocks which also have magneto-plasmonic characteristics. This approach yields nanoparticles with a high density of magnetic and plasmonic functionalities which are uniformly distributed throughout the nanoparticle volume. The hybrid nanoparticles can be easily functionalized by attaching antibodies through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting.

Here, we describe a protocol for synthesis of magneto-plasmonic nanoparticles with a strong magnetic moment and a strong near-infrared (NIR) absorbance. The protocol also includes antibody conjugation to the nanoparticles through the Fc moiety for various biomedical applications which require molecular specific targeting.

Síntese de Immunotargeted magneto-plasmónico Nanoclusters

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications ...

Synthesis of Indoxyl-glycosides for Detection of Glycosidase Activities

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are rapidly oxidized, for example by atmospheric oxygen, to indigo type dyes. This reaction enables fast and easy screening in vivo without isolation or purification of enzymes, as well as rapid tests on agar plates or in solution (e.g., blue-white screening, micro-wells) and is used in biochemistry, histochemistry, bacteriology and molecular biology. Unfortunately the synthesis of such substrates proved to be difficult, due to various side reactions and the low reactivity of the indoxyl hydroxyl function. Especially for glucose type structures low yields were observed. Our novel approach employs indoxylic acid ester as key intermediates. Indoxylic acid esters with varied substitution patterns were prepared on scalable pathways. Phase transfer glycosylations with those acceptors and peracetylated glycosyl halides can be performed under common conditions in high yields. Ester cleavage and subsequent mild silver mediated glycosylation yields the peracetylated indoxyl glycosides in high yields. Finally deprotection is performed according to Zempl&#233;n.

Indoxyl glycosides are well-established and widely used tools for enzyme screening and enzyme activity monitoring. Especially for glucose type structures previous syntheses proved to be challenging and low yielding. Our novel approach employs indoxylic acid esters as precious intermediates to yield a considerable number of indoxyl glycosides in good yields.

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are ...

Fabrication and Testing of Photonic Thermometers

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being leveraged for developing sophisticated photonic sensors. Silicon photonic sensors seek to exploit the strong confinement of light in nano-waveguides to transduce changes in physical state to changes in resonance frequency. In the case of thermometry, the thermo-optic coefficient, i.e., changes in refractive index due to temperature, causes the resonant frequency of the photonic device such as a Bragg grating to drift with temperature. We are developing a suite of photonic devices that leverage recent advances in telecom compatible light sources to fabricate cost-effective photonic temperature sensors, which can be deployed in a wide variety of settings ranging from controlled laboratory conditions, to the noisy environment of a factory floor or a residence. In this manuscript, we detail our protocol for the fabrication and testing of photonic thermometers.

We describe the process of fabrication and testing of photonic thermometers.

Fabricação e teste dos termómetros fotônicos

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being ...

Synthesis of Core-shell Lanthanide-doped Upconversion Nanocrystals for Cellular Applications

Lanthanide-doped upconversion nanocrystals (UCNs) have attracted much attention in recent years based on their promising and controllable optical properties, which allow for the absorption of near-infrared (NIR) light and can subsequently convert it into multiplexed emissions that span over a broad range of regions from the UV to the visible to the NIR. This article presents detailed experimental procedures for high-temperature co-precipitation synthesis of core-shell UCNs that incorporate different lanthanide ions into nanocrystals for efficiently converting deep-tissue penetrable NIR excitation (808 nm) into a strong blue emission at 480 nm. By controlling the surface modification with biocompatible polymer (polyacrylic acid, PAA), the as-prepared UCNs acquires great solubility in buffer solutions. The hydrophilic nanocrystals are further functionalized with specific ligands (dibenzyl cyclooctyne, DBCO) for localization on the cell membrane. Upon NIR light (808 nm) irradiation, the upconverted blue emission can effectively activate the light-gated channel protein on the cell membrane and specifically regulate the cation (e.g., Ca2+) influx in the cytoplasm. This protocol provides a feasible methodology for the synthesis of core-shell lanthanide-doped UCNs and subsequent biocompatible surface modification for further cellular applications.

A protocol is presented for the synthesis of core-shell lanthanide-doped upconversion nanocrystals (UCNs) and their cellular applications for channel protein regulation upon near-infrared (NIR) light illumination.

Síntese de Core-shell Lanthanide dopados com nanocristais de Upconversion para aplicativos de celulares

Lanthanide-doped upconversion nanocrystals (UCNs) have attracted much attention in recent years based on their promising and controllable optical ...

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal structure and probing the hydrogen-bond (H-bond) dynamics of the water molecules adsorbed on solid surfaces are fundamental issues of water science, which remains a great challenge owing to the light mass and small size of hydrogen. Scanning tunneling microscopy (STM) is a promising tool for attacking these problems, thanks to its capabilities of sub-&#197;ngstr&#246;m spatial resolution, single-bond vibrational sensitivity, and atomic/molecular manipulation. The designed experimental system consists of a Cl-terminated tip and a sample fabricated by dosing water molecules in situ onto the Au(111)-supported NaCl(001) surfaces. The insulating NaCl films electronically decouple the water from the metal substrates, so the intrinsic frontier orbitals of water molecules are preserved. The Cl-tip facilitates the manipulation of the single water molecules, as well as gating the orbitals of water to the proximity of Fermi level (EF) via tip-water coupling. This paper outlines the detailed methods of submolecular resolution imaging, molecular/atomic manipulation, and single-bond vibrational spectroscopy of interfacial water. These studies open up a new route for investigating the H-bonded systems at the atomic scale.

Here, we present a protocol to investigate the structure and dynamics of interfacial water at the atomic scale, in terms of submolecular resolution imaging, molecular manipulation, and single-bond vibrational spectroscopy.

Sondagem da Estrutura e Dinâmica da Água Interfacial com Microscopia de Tunelamento de Varredura e Espectroscopia

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

Síntese de nanofios de Au substrato ligados através de um mecanismo de crescimento ativo de superfície

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

Escherichia coli-Based Cell-Free Protein Synthesis: Protocols for a robust, flexible, and accessible platform technology

Over the last 50 years, Cell-Free Protein Synthesis (CFPS) has emerged as a powerful technology to harness the transcriptional and translational capacity of cells within a test tube. By obviating the need to maintain the viability of the cell, and by eliminating the cellular barrier, CFPS has been foundational to emerging applications in biomanufacturing of traditionally challenging proteins, as well as applications in rapid prototyping for metabolic engineering, and functional genomics. Our methods for implementing an E. coli-based CFPS platform allow new users to access many of these applications. Here, we describe methods to prepare extract through the use of enriched media, baffled flasks, and a reproducible method of tunable sonication-based cell lysis. This extract can then be used for protein expression capable of producing 900 &#181;g/mL or more of super folder green fluorescent protein (sfGFP) in just 5 h from experimental setup to data analysis, given that appropriate reagent stocks have been prepared beforehand. The estimated startup cost of obtaining reagents is $4,500 which will sustain thousands of reactions at an estimated cost of $0.021 per &#181;g of protein produced or $0.019 per &#181;L of reaction. Additionally, the protein expression methods mirror the ease of the reaction setup seen in commercially available systems due to optimization of reagent pre-mixes, at a fraction of the cost. In order to enable the user to leverage the flexible nature of the CFPS platform for broad applications, we have identified a variety of aspects of the platform that can be tuned and optimized depending on the resources available and the protein expression outcomes desired.

Escherichia coli-Based Cell-Free Protein Synthesis: Protocols for a robust, flexible, and accessible platform technology

This protocol details the steps, costs, and equipment necessary to generate E. coli-based cell extracts and implement in vitro protein synthesis reactions within 4 days or less. To leverage the flexible nature of this platform for broad applications, we discuss reaction conditions that can be adapted and optimized.

Escherichia coli-baseado sem célula de síntese de proteínas: protocolos para uma tecnologia de plataforma robusta, flexível e acessível

Over the last 50 years, Cell-Free Protein Synthesis (CFPS) has emerged as a powerful technology to harness the transcriptional and translational capacity ...

Synthesis of In37P20(O2CR)51 Clusters and Their Conversion to InP Quantum Dots

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 clusters have been observed as intermediates in the synthesis of InP quantum dots from molecular precursors (In(O2CR)3, HO2CR, and P(SiMe3)3) and may be isolated as a pure reagent for subsequent study and use as a single-source precursor. These clusters readily convert to crystalline and relatively monodisperse samples of quasi-spherical InP quantum dots when subjected to thermolysis conditions in the absence of additional precursors above 200 &#176;C. The optical properties, morphology, and structure of both the clusters and quantum dots are confirmed using UV-Vis spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, and powder X-ray diffraction. The molecular symmetry of the clusters is additionally confirmed by solution-phase 31P NMR spectroscopy. This protocol demonstrates the preparation and isolation of atomically-precise InP clusters, and their reliable and scalable conversion to InP QDs.

Synthesis of In37P20O2CR51 Clusters and Their Conversion to InP Quantum Dots

A protocol for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots is presented.

Síntese de37P20(O2CR)51 clusters e sua conversão para pontos Quantum INP

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 ...

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands for in vivo investigations. Within this protocol, a robust and reliable remote-controlled radiosynthesis of [11C]SNAP-7941, an antagonist to the melanin-concentrating hormone receptor 1, is described. The radiosynthesis starts with cyclotron produced [11C]CO2 that is subsequently further reacted via a gas-phase transition to [11C]CH3OTf. Then, this reactive intermediate is introduced to the precursor solution and forms the respective radiotracer. Chemical as well as the radiochemical purity are determined by means of RP-HPLC, routinely implemented in the radiopharmaceutical quality control process. Additionally, the molar activity is calculated as it is a necessity for the following real-time kinetic investigations. Furthermore, [11C]SNAP-7941 is applied to MDCKII-WT and MDCKII-hMDR1 cells for evaluating the impact of P-glycoprotein (P-gp) expression on cell accumulation. For this reason, the P-gp expressing cell line (MDCKII-hMDR1) is either used without or with blocking prior to experiments by means of the P-gp substrate (&#177;)-verapamil and the results are compared to the ones observed for the wildtype cells. The overall experimental approach demonstrates the importance of a precise time-management that is essential for every preclinical and clinical study using PET tracers radiolabelled with short-lived nuclides, such as carbon-11 (half-life: 20 min).

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Here, we represent a protocol for the fully automated radiolabelling of [11C]SNAP-7941 and the analysis of the real-time kinetics of this PET-tracer on P-gp expressing and non-expressing cells.

Aspecto técnico da síntese automatizada e avaliação cinética em tempo real de [11C] SNAP-7941

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands ...

Síntese de Cd-livre InP / ZnS Quantum Dots Indicado para aplicações biomédicas

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