The role of nanostructure in the wetting behavior of mixed-monolayer-protected metal nanoparticles

Centrone, Andrea; Penzo, Erika; Sharma, Munish; Myerson, Jacob W.; Jackson, Alicia M.; Marzari, Nicola; Stellacci, Francesco

doi:10.1073/pnas.0803929105

Cited by 108 publications

(110 citation statements)

References 37 publications

(44 reference statements)

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“…The molecular detail of the solvent, however, becomes important for nanoparticles (in the size range 1-10 nm) and so the utility of macroscopic expressions may be questionable. This is becoming particularly relevant as, with the increasing sophistication of nanoparticle synthesis techniques, the creation of nm-scale particles with well defined surface topologies, 23 with feature sizes comparable to the solvent molecules, is possible.…”

Section: 12mentioning

confidence: 99%

Stability of Janus nanoparticles at fluid interfaces

Cheung

Bon

2009

Soft Matter

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Using Monte Carlo simulations the interaction of a nanometre-sized, spherical Janus particle (a particle with two distinct surface regions of different functionality, in this case showing amphiphilic behaviour) with an ideal fluid interface is studied. In common with previous simulations of spherical, isotropic particles, the range of the nanoparticle-interface interaction is significantly larger than the nanoparticle radius due to the broadening of the interface due to capillary waves. For a uniform particle (an isotropic particle with one surface characteristic) the stability of the particle at a liquid interface is decreased as the affinity for one liquid phase is increased relative to the other; for large affinity differences the detachment energies calculated from continuum theory become increasingly accurate. For a symmetric Janus particle (where the two different surface regions are of equal area), the presence of the particle at the interface becomes more stable upon increasing the difference in affinity between the two faces, with each face having a high affinity for the respective liquid phase. In the case studied here, where surface tension between the A-region of the particle with the A-component is identical to the surface tension between the B-region and B-component, the interaction is symmetric with respect to the nanoparticle interface separation. The particle is found to have a large degree of orientational freedom, in sharp contrast to micrometre-sized colloidal particles. Comparison with continuum theory shows that this significantly overestimates the detachment energy, due to its neglect of nanoparticle rotation; simulations of nanoparticles with fixed orientations show a considerably larger detachment energy. As the areas of the surface regions become asymmetric the stability of the Janus nanoparticle is decreased and, in the case of large differences in affinities of the two faces, the difference between detachment energies from simulation and continuum theory diminishes.

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Section: 12mentioning

confidence: 99%

Stability of Janus nanoparticles at fluid interfaces

Cheung

Bon

2009

Soft Matter

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“…It has been pointed out in different papers that these ligands can arrange themselves into surface domains ( patches), hence providing new interfacial properties to the NPs. [36][37][38] Among these arrangements, Janus (two different sides), narrow nanodomains (stripes) and uniformly mixed morphologies have been reported in experimental and theoretical papers. [39][40][41] The size of NPs, chemical nature of the ligands and their arrangement at the surface affect their interaction with interfaces and therefore their use in different applications.…”

Section: Introductionmentioning

confidence: 99%

Contact angle and adsorption energies of nanoparticles at the air–liquid interface determined by neutron reflectivity and molecular dynamics

et al. 2015

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Understanding how nanomaterials interact with interfaces is essential to control their self-assembly as well as their optical, electronic, and catalytic properties. We present here an experimental approach based on neutron reflectivity (NR) that allows the in situ measurement of the contact angles of nanoparticles adsorbed at fluid interfaces. Because our method provides a route to quantify the adsorption and interfacial energies of the nanoparticles in situ, it circumvents problems associated with existing indirect methods, which rely on the transport of the monolayers to substrates for further analysis. We illustrate the method by measuring the contact angle of hydrophilic and hydrophobic gold nanoparticles, coated with perdeuterated octanethiol (d-OT) and with a mixture of d-OT and mercaptohexanol (MHol), respectively.The contact angles were also calculated via atomistic molecular dynamics (MD) computations, showing excellent agreement with the experimental data. Our method opens the route to quantify the adsorption of complex nanoparticle structures adsorbed at fluid interfaces featuring different chemical compositions.

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“…Here we study NPs consisting of an inorganic gold core coated with a self-assembled monolayer (SAM) of thiolated organic molecules [9]. These surface-bound molecules, or ligands, determine the solubility of the NPs in addition to providing a facile scaffold for additional modification [10,11], such as the surface conjugation of fluorescent makers, targeting agents or therapeutic agents [12,13]. However, the study of the supramolecular interactions between the surface ligands and their biological environment is in its infancy, especially for the case of mixed-ligand systems.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Cellular Uptake of Mixed-Monolayer Protected Nanoparticles

Carney

Mueller

et al. 2012

Biointerphases

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Nanoparticles (NPs) are gaining increasing attention for potential application in medicine; consequently, studying their interaction with cells is of central importance. We found that both ligand arrangement and composition on gold nanoparticles play a crucial role in their cellular internalization. In our previous investigation, we showed that 66-34OT nanoparticles coated with stripe-like domains of hydrophobic (octanethiol, OT, 34%) and hydrophilic (11-mercaptoundecane sulfonate, MUS, 66%) ligands permeated through the cellular lipid bilayer via passive diffusion, in addition to endo-/pino-cytosis. Here, we show an analysis of NP internalization by DC2.4, 3T3, and HeLa cells at two temperatures and multiple time points. We study four NPs that differ in their surface structures and ligand compositions and report on their cellular internalization by intracellular fluorescence quantification. Using confocal laser scanning microscopy we have found that all three cell types internalize the 66-34OT NPs more than particles coated only with MUS, or particles coated with a very similar coating but lacking any detectable ligand shell structure, or 'striped' particles but with a different composition (34-66OT) at multiple data points.

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The role of nanostructure in the wetting behavior of mixed-monolayer-protected metal nanoparticles

Cited by 108 publications

References 37 publications

Stability of Janus nanoparticles at fluid interfaces

Stability of Janus nanoparticles at fluid interfaces

Contact angle and adsorption energies of nanoparticles at the air–liquid interface determined by neutron reflectivity and molecular dynamics

Dynamic Cellular Uptake of Mixed-Monolayer Protected Nanoparticles

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