Reversible Clustering of Gold Nanoparticles under Confinement

Sánchez‐Iglesias, Ana; Claes, Nathalie; Solís, Diego M.; Taboada, J. M.; Bals, Sara; Liz‐Marzán, Luis M.; Grzelczak, Marek

doi:10.1002/anie.201800736

Cited by 53 publications

(67 citation statements)

References 22 publications

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“…The complicated yolk-shell structure is beyond the capability of conventional TEM and HAADF-STEM analysis, especially the details on the nanocrystal spatial distributions and ordering (Figure 8a). [109] As shown in Figure 8d, the isolated Au@polystyrene particles aggregate together in water, and redisperse themselves back in tetrahydrofuran (THF). Interestingly, the yolk structure is not necessarily unalterable, a recent report reveals the reversible clustering of gold nanoparticles confined within a hollow silica sphere.…”

Section: Core-shell/yolk-shell Nanoparticles With Intricate Nanostrucmentioning

confidence: 97%

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Electron Tomography: A Unique Tool Solving Intricate Hollow Nanostructures

et al. 2018

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Innovations in nanofabrication have expedited advances in hollow-structured nanomaterials with increasing complexity, which, at the same time, set challenges for the precise determination of their intriguing and complicated 3D configurations. Conventional transmission electron microscopy (TEM) analysis typically yields 2D projections of 3D objects, which in some cases is insufficient to reflect the genuine architectures of these 3D nano-objects, providing misleading information. Advanced analytical approaches such as focused ion beam (FIB) and ultramicrotomy enable the real slicing of nanomaterials, realizing the direct observation of inner structures but with limited spatial discrimination. Electron tomography (ET) is a technique that retrieves spatial information from a series of 2D electron projections at different tilt angles. As a unique and powerful tool kit, this technique has experienced great advances in its application in materials science, resolving the intricate 3D nanostructures. Here, the exceptional capability of the ET technique in the structural, chemical, and quantitative analysis of hollow-structured nanomaterials is discussed in detail. The distinct information derived from ET analysis is highlighted and compared with conventional analysis methods. Along with the advances in microscopy technologies, the state-of-the-art ET technique offers great opportunities and promise in the development of hollow nanomaterials.

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Section: Core-shell/yolk-shell Nanoparticles With Intricate Nanostrucmentioning

confidence: 97%

Section: Chemical Analysismentioning

confidence: 99%

Electron Tomography: A Unique Tool Solving Intricate Hollow Nanostructures

et al. 2018

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“…2019, 8,1900575 www.advancedsciencenews.com www.advhealthmat.de for validating the correct H7 gene. Healthcare Mater.…”

Section: Detection Of Pcr-validated Samplementioning

confidence: 99%

“…

Those sensors increase the limits of detection (LOD) by using signal amplifiers but the hybridization times are usually long. [8,9] Despite the advantages, AuNPs are surface-sensitive and may induce undesired aggregations due to high ionic strength and concentration of ions, resulting in false-positive signals.Apart from those approaches, optical detection has drawn substantial attention because of their simplicity, sensitiveness, and multiplexity. The simplicity in design and readout of these sensors had attracted substantial attention.

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confidence: 99%

Upconversion Luminescence Sandwich Assay For Detection of Influenza H7 Subtype

Tsang

Wong

Tsoi

et al. 2019

Adv Healthcare Materials

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Those sensors increase the limits of detection (LOD) by using signal amplifiers but the hybridization times are usually long. [7] On the other hand, colorimetric sensor produce visible color changes upon the presence of the virus genes. The simplicity in design and readout of these sensors had attracted substantial attention. Gold nanoparticles (AuNPs) are one of the promising candidates for such detection strategy because of their high extinction coefficient and aggregation-dependent color change. [8,9] Despite the advantages, AuNPs are surface-sensitive and may induce undesired aggregations due to high ionic strength and concentration of ions, resulting in false-positive signals.Apart from those approaches, optical detection has drawn substantial attention because of their simplicity, sensitiveness, and multiplexity. [10,11] It is the fact that organic dyes are widely used in conventional qPCR assays via downconversion processes. [4,12,13] However, the dyes demonstrate undesirable emissive properties such as poor photostability, broad emission band, and small Stokes shift. [14] Therefore, they were usually employed as quenchers in nanoparticle-based detection systems. [15][16][17] High energy excited quantum dots (QDs) are another representative fluorophores in downconverting assays. [18][19][20] The excitation may induce background fluorescence and broad emission peaks, contributing to severe cross-talking problem. To address these limitations, nearinfrared (NIR) triggered upconversion luminescence (UCL) in lanthanide-doped upconversion nanoparticles (UCNPs) is very promising in biodetection. They not only display large anti-Stokes shift [21,22] but also pose minimal damage to the gene oligos. In addition, the long-lived UCL signal is easily distinguished from the short-lived background signal. As a result, UCNPs were used to detect different oligos and analytes. [23][24][25][26][27][28] The assays involved highly distance-dependent luminescence resonance energy transfer (LRET) between energy donor and acceptor, in which the luminescent intensity changes with the separation between the energy pair. [29] In this work, green emitting UCNPs and AuNPs are selected as the LRET pair owing to their well-matched emission and extinction spectrum, while AuNPs exhibit excellent extinction coefficient and photostability. The size of the nanoparticles played important roles in hybridization [30] because AuNPs demonstrate sizedependent absorption property and it can alter the stability of the hybridized DNA duplex. In addition, the size ratios of the UCNPs and AuNPs affect the formation of UCNPs-AuNPs hybrid structures. Taking advantages of 808 nm excitation of With large anti-Stokes shifts and background-free signals, upconversion luminescent (UCL) screening assays have been a promising method to reduce the transmission of influenza epidemic, which can critically alleviate the disease burden and extra annual deaths. In this work, a luminescent resonance energy transfer sandwich assay is developed, which utilizes core-shell...

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“…Fifth, in virtually all of the examples covered in this review, light‐induced self‐assembly of NPs was carried out in bulk solution. Different dynamics of self‐assembly and morphologies of the assembled structures can be expected for processes carried out in other environments, such as at a liquid–air interface and inside confined spaces . Sixth, an important outstanding challenge is to reversibly control the self‐assembly of NPs using light in biological environments, which can lead to novel ways of modulating biological functions and treating diseases.…”

Section: Discussionmentioning

confidence: 99%

The Many Ways to Assemble Nanoparticles Using Light

2019

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The ability to reversibly assemble nanoparticles using light is both fundamentally interesting and important for applications ranging from reversible data storage to controlled drug delivery. Here, the diverse approaches that have so far been developed to control the self-assembly of nanoparticles using light are reviewed and compared. These approaches include functionalizing nanoparticles with monolayers of photoresponsive molecules, placing them in photoresponsive media capable of reversibly protonating the particles under light, and decorating plasmonic nanoparticles with thermoresponsive polymers, to name just a few. The applicability of these methods to larger, micrometer-sized particles is also discussed. Finally, several perspectives on further developments in the field are offered.

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Reversible Clustering of Gold Nanoparticles under Confinement

Cited by 53 publications

References 22 publications

Electron Tomography: A Unique Tool Solving Intricate Hollow Nanostructures

Electron Tomography: A Unique Tool Solving Intricate Hollow Nanostructures

Upconversion Luminescence Sandwich Assay For Detection of Influenza H7 Subtype

The Many Ways to Assemble Nanoparticles Using Light

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