Light-controlled self-assembly of reversible and irreversible nanoparticle suprastructures

Klajn, Rafał; Bishop, Kyle J. M.; Grzybowski, Bartosz A.

doi:10.1073/pnas.0611371104

Cited by 407 publications

(394 citation statements)

References 20 publications

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“…Although a variety of gold nanoparticle (Au NP) supraspheres have been prepared [14][15][16][17] , the hydrophobically driven formation of analogous assemblies in pure water remains elusive [18][19][20][21] . The main obstacle is that precipitation rapidly results from a lack of control over the aggregation processes 19 .…”

Section: Hydrophobically Driven Assembly In Watermentioning

confidence: 99%

Host–guest chemistry with water-soluble gold nanoparticle supraspheres

et al. 2016

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The uptake of molecular guests, a hallmark of the supramolecular chemistry of cages and containers, has yet to be documented for soluble assemblies of metal nanoparticles. Here we demonstrate that gold nanoparticle-based supraspheres serve as a host for the hydrophobic uptake, transport and subsequent release of over two million organic guests, exceeding by five orders of magnitude the capacities of individual supramolecular cages or containers and rivalling those of zeolites and metal-organic frameworks on a mass-per-volume basis. The supraspheres are prepared in water by adding hexanethiol to polyoxometalate-protected 4 nm gold nanoparticles. Each 200 nm assembly contains hydrophobic cavities between the estimated 27,400 gold building blocks that are connected to one another by nanometre-sized pores. This gives a percolated network that effectively absorbs large numbers of molecules from water, including 600,000, 2,100,000 and 2,600,000 molecules (35, 190 and 234 g l ) of para-dichorobenzene, bisphenol A and trinitrotoluene, respectively.H ost-guest phenomena that involve the uptake of gases and small molecules are associated with the supramolecular chemistry of soluble capsules, cages and containers [1][2][3][4][5] or, alternatively, with heterogeneous reactions of porous solid-state materials such as zeolites 6 and metal-organic frameworks 7 . Only now, however, are organized assemblies of metal nanoparticles beginning to serve in a similar capacity as hosts for molecular guests. In organic solvents, for example, light-induced dipoledipole interactions between gold nanoparticles with azobenzenefunctionalized thiolate ligands were recently used to entrap and catalyse the reactions of polar and alkylaromatic substrates 8 . By design, substrates were entrapped during nanoparticle aggregation to overcome the poor uptake and diffusion of molecular guests into colloidal nanocrystal assemblies. However, the uptake of molecular guests, a trait of supramolecular and solid-state chemistry, has so far not been achieved for colloidal nanoparticle assemblies.For that to occur, a thermodynamically favourable driving force must be combined with a porous structure whose interior architecture features host cavities, along with pathways for the effective diffusion of molecular guests from the exterior (bulk solution) to host domains deeply buried in the assembly's interior. If this were achieved, colloidal metal-nanoparticle assemblies could emerge as a new class of functional nano-engineered structures that are uniquely positioned between supramolecular containers and porous solid-state materials.We report a new class of functional assemblies, wherein the hydrophobic effect 9,10 drives the spontaneous uptake of alkyl and alkylaromatic guests 11 by porous 200 nm diameter supraspheres whose host capacities are orders of magnitude larger than those of individual cages or containers. On a mass-per-volume basis, the level of uptake rivals those of zeolites and metal-organic frameworks, which, for methane at elevated pressures, r...

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Section: Hydrophobically Driven Assembly In Watermentioning

confidence: 99%

Host–guest chemistry with water-soluble gold nanoparticle supraspheres

et al. 2016

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“…Externally applied light, magnetic, electric, and acoustic fields can drive symmetric particles into ordered arrays (4)(5)(6)(7). Colloidal Janus particles selfassemble into complex structures by various mechanisms (8)(9)(10)(11)(12).…”

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Catalytically powered dynamic assembly of rod-shaped nanomotors and passive tracer particles

Wang

Duan

Sen

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

183

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Nano-and microscale motors powered by catalytic reactions exhibit collective behavior such as swarming, predator-prey interactions, and chemotaxis that resemble those of biological microorganisms. A quantitative understanding of the catalytically generated forces between particles that lead to these behaviors has so far been lacking. Observations and numerical simulations of pairwise interactions between gold-platinum nanorods in hydrogen peroxide solutions show that attractive and repulsive interactions arise from the catalytically generated electric field. Electrokinetic effects drive the assembly of staggered doublets and triplets of nanorods that are moving in the same direction. None of these behaviors are observed with nanorods composed of a single metal. The motors also collect tracer microparticles at their head or tail, depending on the charge of the particles, actively assembling them into close-packed rafts and aggregates of rafts. These motor-tracer particle interactions can also be understood in terms of the catalytically generated electric field around the ends of the nanorod motors.dynamic interactions | self-assembly | colloidal transport T he dynamic interactions between moving objects, in particular their response to external stimuli and their communication with each other, govern their collective behavior on many length scales. Schooling of fish and flocking of birds are good examples of emergent phenomena that are orchestrated by communication between individuals in a large group. In these systems, macroscale organization is typically driven by nearest neighbor interactions that follow simple rules. To reach the level of organization seen in such living assemblies, fast and precise (in terms of distances, angles, and velocities) communication and control are required from the members. It is now straightforward to create computational models from which such dynamic structures emerge, but artificial systems that mimic behaviors as complicated as fish schooling have very rarely been realized experimentally in macroscopic engineered systems (1). On the other hand, self-assembly at the nano-and molecular levels already demonstrates a certain level of complexity and has furthered our understanding of dynamic interactions at small scales (2, 3).There are already many examples of particle assembly driven by local forces or externally applied fields. Externally applied light, magnetic, electric, and acoustic fields can drive symmetric particles into ordered arrays (4-7). Colloidal Janus particles selfassemble into complex structures by various mechanisms (8-12). However, in these examples the particle aggregates hardly approach the complexity of assemblies of living organisms; the interactions are passive responses to local forces and external fields with very limited interparticle communication or active response to the behavior of nearest neighbors.Interactions between active particles, on the other hand, can more closely mimic those of living organisms (13-17). Powered particles generate signals, t...

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“…In most of these, tailoring the plasmon resonance to a desired spectral position is crucial to overlap plasmonic resonances with appropriate electronic or molecular transitions. Significant efforts have been devoted to creating tuneable plasmonic systems, eliciting several approaches such as wet chemistry modification,5 top‐down fabrication,6 dynamic self‐assembly and disassembly,7, 8, 9, 10 electrical tuning,11 and mechanical stretching 12. The basic general principle is to change the size, shape, surroundings, or distance between different plasmonic components which tunes the surface plasmon resonance.…”

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confidence: 99%