Hybrid nanostructures composed of metal nanoparticles and metal‐organic frameworks (MOFs) have recently received increasing attention toward various applications due to the combination of optical and ...catalytic properties of nanometals with the large internal surface area, tunable crystal porosity and unique chemical properties of MOFs. Encapsulation of metal nanoparticles of well‐defined shapes into porous MOFs in a core–shell type configuration can thus lead to enhanced stability and selectivity in applications such as sensing or catalysis. In this study, the encapsulation of single noble metal nanoparticles with arbitrary shapes within zeolitic imidazolate‐based metal organic frameworks (ZIF‐8) is demonstrated. The synthetic strategy is based on the enhanced interaction between ZIF‐8 nanocrystals and metal nanoparticle surfaces covered by quaternary ammonium surfactants. High resolution electron microscopy and tomography confirm a complete core–shell morphology. Such a well‐defined morphology allowed us to study the transport of guest molecules through the ZIF‐8 porous shell by means of surface‐enhanced Raman scattering by the metal cores. The results demonstrate that even molecules larger than the ZIF‐8 aperture and pore size may be able to diffuse through the framework and reach the metal core.
A general strategy for the encapsulation of individual metal nanoparticles with the zeolitic imidazolate frameworks ZIF‐8 is described. The presence of plasmonic nanoparticles as cores allows to study the transport of different guest molecules inside the ZIF‐8 shell by means of SERS. The results demonstrate the ability of ZIF‐8 to incorporate molecules larger than the nominal aperture and pore size.
We report here fast A‐site cation cross‐exchange between APbX3 perovskite nanocrystals (NCs) made of different A‐cations (Cs (cesium), FA (formamidinium), and MA (methylammonium)) at room ...temperature. Surprisingly, the A‐cation cross‐exchange proceeds as fast as the halide (X=Cl, Br, or I) exchange with the help of free A‐oleate complexes present in the freshly prepared colloidal perovskite NC solutions. This enabled the preparation of double (MACs, MAFA, CsFA)‐ and triple (MACsFA)‐cation perovskite NCs with an optical band gap that is finely tunable by their A‐site composition. The optical spectroscopy together with structural analysis using XRD and atomically resolved high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and integrated differential phase contrast (iDPC) STEM indicates the homogeneous distribution of different cations in the mixed perovskite NC lattice. Unlike halide ions, the A‐cations do not phase‐segregate under light illumination.
The A‐cation cross‐exchange between perovskite nanocrystals (NCs) is found to be as fast as the halide exchange in the presence of excess A‐oleate complexes in the colloidal solution. The synthesis of a wide range of mixed (double and triple)‐cation and mixed halide perovskite NCs is demonstrated. The mixed A‐cations were found to be uniformly distributed across the crystal lattice and they do not segregate under intense light illumination.
A robust and reproducible methodology to prepare stable inorganic nanoparticles with chiral morphology may hold the key to the practical utilization of these materials. An optimized chiral growth ...method to prepare fourfold twisted gold nanorods is described herein, where the amino acid cysteine is used as a dissymmetry inducer. Four tilted ridges are found to develop on the surface of single‐crystal nanorods upon repeated reduction of HAuCl4, in the presence of cysteine as the chiral inducer and ascorbic acid as a reducing agent. From detailed electron microscopy analysis of the crystallographic structures, it is proposed that the dissymmetry results from the development of chiral facets in the form of protrusions (tilted ridges) on the initial nanorods, eventually leading to a twisted shape. The role of cysteine is attributed to assisting enantioselective facet evolution, which is supported by density functional theory simulations of the surface energies, modified upon adsorption of the chiral molecule. The development of R‐type and S‐type chiral structures (small facets, terraces, or kinks) would thus be non‐equal, removing the mirror symmetry of the Au NR and in turn resulting in a markedly chiral morphology with high plasmonic optical activity.
Fourfold twisted Au nanorods can be prepared via chiral seeded growth, using cysteine as a chiral inducer. A high dissymmetry factor is obtained and electromagnetic simulations show chiral plasmon modes with largely asymmetric near‐field enhancement. The mechanism involved in chiral growth is related with cysteine‐induced enantioselective development of chiral facets.
Shape control in gold nanoparticle synthesis Grzelczak, Marek; Pérez-Juste, Jorge; Mulvaney, Paul ...
Chemical Society reviews,
09/2008, Letnik:
37, Številka:
9
Journal Article
Recenzirano
In this tutorial review, we summarise recent research into the controlled growth of gold nanoparticles of different morphologies and discuss the various chemical mechanisms that have been proposed to ...explain anisotropic growth. With the overview and discussion, we intended to select those published procedures that we consider more reliable and promising for synthesis of morphologies of interest. We expect this to be interesting to researchers in the wide variety of fields that can make use of metal nanoparticles.
Zeolitic imidazolate framework-8 (ZIF-8) is a metal organic framework with exceptional intrinsic properties, high tunability, cost effectiveness, and producibility, which has boosted the research ...development of the field. ZIF-8-based materials have shown high capabilities for multiple purposes as catalysts, capacitors, electrodes, drug delivery systems, or adsorption/separation membranes. Herein, we report the synergistic combination of ZIF-8, plasmonic nanoparticles, and rationally designed protein adaptors and antibodies for fabricating novel surface-enhanced Raman scattering (SERS) tags with enhanced sensing capabilities. The SERS tags consist of Au@Ag core–shell nanorods individually encapsulated within a multifunctional ZIF-8 matrix encoded with Raman reporters. While the role of the plasmonic core is to enhance the Raman, the ZIF-8 traps the Raman active molecules and, more importantly, facilitates the active targeting of the SERS tag surface through the modular assembly with conventional (i.e., immunoglobulins) and recombinant antibodies (i.e., nanobodies) mediated by the specific interaction of Zn2+ with polyhistidine-tagged protein G and SpyCatcher. Evidence of the capabilities of the Au@Ag@ZIF-8 nanotags for the SERS detection of EGFR and CD44 cell surface receptors in vitro illustrates the potential of these optical nanoprobes for imaging and multiplex biodetection. The reported modular assembly approach for the functionalization of ZIF-8 SERS nanotags with different classes of antibodies based on polyhistidine-tagged peptides and protein–protein interactions can not only be applied to the ever-increasing number of reported MOFs structures but also can be further exploited as a universal means for the functionalization of other transition metal surfaces.
Plasmonic metal‐organic frameworks are composite nanoparticles comprising plasmonic metal nanoparticles (NPs) embedded within a metal‐organic framework (MOF) matrix. As a result, not only the ...functionalities of the individual components are retained, but synergistic effects additionally provide improved chemical and physical properties. Recent progress in plasmonic MOFs has demonstrated the potential for nanofabrication and various nanotechnology applications. Synthetic challenges toward plasmonic MOFs have been recently addressed, resulting in new opportunities toward practical applications, such as surface‐enhanced Raman scattering, therapy, and catalysis. The impact of key parameters (thermodynamic vs. kinetic) on the synthetic pathways of plasmonic MOFs is reviewed, while providing insight into related progress toward structure‐derived applications.
Plasmonic metal‐organic frameworks hybrid nanocomposites feature improved chemical and physical properties, as compared with their individual components, due to synergistic performance. These materials show excellent opportunities toward practical applications, such as surface‐enhanced Raman scattering, therapy, and catalysis.
In this minireview, we summarize current research dealing with the combination of noble‐metal nanoparticles and different families of supramolecular macrocycles (cyclodextrins, cucurbitnurils, ...calixarenes, and pillarnarenes). We intended to select relevant publications on the synthesis of noble‐metal nanoparticles with macrocycles acting as capping agents or/and reducing agents, as well as on the post‐synthetic metal‐nanoparticle modification with macrocycles. We also discuss strategies in which supramolecular chemistry is applied to direct the self‐assembly of nanoparticles and formation of polymer composites. We finally describe the main applications of these materials in various fields.
Nanoparticles and macrocycles: Recent literature regarding the combination of supramolecular macrocycles and metal nanoparticles is reviewed, with particular emphasis on the synthesis, surface modification and assembly, as well as the potential applications of the obtained nanocomposites (SERS = surface‐enhanced Raman spectroscopy).
Plasmonic Supercrystals García-Lojo, Daniel; Núñez-Sánchez, Sara; Gómez-Graña, Sergio ...
Accounts of chemical research,
07/2019, Letnik:
52, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Conspectus For decades, plasmonic nanoparticles have been extensively studied due to their extraordinary properties, related to localized surface plasmon resonances. A milestone in the field has been ...the development of the so-called seed-mediated growth method, a synthetic route that provided access to an extraordinary diversity of metal nanoparticles with tailored size, geometry and composition. Such a morphological control came along with an exquisite definition of the optical response of plasmonic nanoparticles, thereby increasing their prospects for implementation in various fields. The susceptibility of surface plasmons to respond to small changes in the surrounding medium or to perturb (enhance/quench) optical processes in nearby molecules, has been exploited for a wide range of applications, from biomedicine to energy harvesting. However, the possibilities offered by plasmonic nanoparticles can be expanded even further by their careful assembly into either disordered or ordered structures, in 2D and 3D. The assembly of plasmonic nanoparticles gives rise to coupling/hybridization effects, which are strongly dependent on interparticle spacing and orientation, generating extremely high electric fields (hot spots), confined at interparticle gaps. Thus, the use of plasmonic nanoparticle assemblies as optical sensors have led to improving the limits of detection for a wide variety of (bio)molecules and ions. Importantly, in the case of highly ordered plasmonic arrays, other novel and unique optical effects can be generated. Indeed, new functional materials have been developed via the assembly of nanoparticles into highly ordered architectures, ranging from thin films (2D) to colloidal crystals or supercrystals (3D). The progress in the design and fabrication of 3D supercrystals could pave the way toward next generation plasmonic sensors, photocatalysts, optomagnetic components, metamaterials, etc. In this Account, we summarize selected recent advancements in the field of highly ordered 3D plasmonic superlattices. We first analyze their fascinating optical properties for various systems with increasing degrees of complexity, from an individual metal nanoparticle through particle clusters with low coordination numbers to disordered self-assembled structures and finally to supercrystals. We then describe recent progress in the fabrication of 3D plasmonic supercrystals, focusing on specific strategies but without delving into the forces governing the self-assembly process. In the last section, we provide an overview of the potential applications of plasmonic supercrystals, with a particular emphasis on those related to surface-enhanced Raman scattering (SERS) sensing, followed by a brief highlight of the main conclusions and remaining challenges.
Hydrophobic interactions constitute one of the most important types of nonspecific interactions in biological systems, which emerge when water molecules rearrange as two hydrophobic species come ...close to each other. The prediction of hydrophobic interactions at the level of nanoparticles (Brownian objects) remains challenging because of uncontrolled diffusive motion of the particles. We describe here a general methodology for solvent-induced, reversible self-assembly of gold nanoparticles into 3D clusters with well-controlled sizes. A theoretical description of the process confirmed that hydrophobic interactions are the main driving force behind nanoparticle aggregation.
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•Living cells are sensor/actuator entities that perceive and process chemical and physical stimuli by receptor-mediated cell signaling, which in turn modulates cellular function and ...behavior.•Gold nanoparticles and gold nanostructured substrates have unique chemical and physical properties that allow targeted modulation of cell receptor function at the nanoscale.•Multifunctional gold-based nanodevices enable biochemical, plasmonic (e.g. optothermal) and electrical manipulation of cell activities at the nanoscale.
The cell possesses the remarkable ability to perceive and process chemical and physical stimuli, which in turn modulate cellular behavior. One of the great wonders about nanotechnology is that it enables the fabrication of tools on the same length scale as biomolecules, thereby providing us with a unique handle for characterizing and controlling basic cellular processes. Owing to their tunable size and shape dependent physical properties, biocompatibility and facile surface modification, gold nanoparticles become potentially powerful tools to probe fundamental aspects of cell biology. Consequently, innovative approaches based on gold nanoparticles are under development toward the manipulation of cell function and improvement of techniques currently used in biomedicine and biotechnology. In this review we provide an overview of recent applications based on gold nanoparticles and nanostructured materials for the modulation of cellular activity and behavior, mediated by their interactions with cell surface receptors.
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