Adenosine-Monophosphate-Assisted Homogeneous Silica Coating of Silver Nanoparticles in High Yield.

In this study, we propose a novel approach for the silica coating of silver nanoparticles based on surface modification with adenosine monophosphate (AMP). Upon AMP stabilization, the nanoparticles can be transferred into 2-propanol, promoting the growth of silica on the particle surfaces through the standard Stöber process. The obtained silica shells are uniform and homogeneous, and the method allows a high degree of control over shell thickness while minimizing the presence of uncoated NPs or the negligible presence of core-free silica NPs.

Silver and Copper Acute Effects on Membrane Proteins and Impact on Photosynthetic and Respiratory Complexes in Bacteria.

Silver (Ag) and copper (Cu) ions have been used for centuries in industry, as well as antimicrobial agents in agriculture and health care. Nowadays, Ag is also widely used in the field of nanotechnology. Yet, the underlying mechanisms driving toxicity of Ag ions are poorly characterized.

Enhancement of Ag cluster mobility on Ag surfaces by chloridation.

To understand the role of chlorine in the stability and the observed fragmentation of Ag dendritic nanostructures, we have studied computationally two model systems using density functional theory. The first one relates to diffusion of Ag(n) and Ag(n)Cl(m) (n = 1-4) clusters on an Ag(111) surface, and the second demonstrates interaction strength of (Ag(55))(2) dimers with and without chloridation. Based on our calculated energy barriers, Ag(n)Cl(m) clusters are more mobile than Ag(n) clusters for n = 1-4.

Coarsening and pearling instabilities in silver nanofractal aggregates.

We investigate the morphological changes of 3D supported fractal aggregates generated through the deposition of silver clusters on graphite. The fractal relaxation, activated after their formation by perturbing them either by thermal annealing or by using a surfactant, as oxide molecules, carried by silver clusters in a subsequent deposition, shows evidence of two distinct fragmentation patterns. The post coarsening, driven by thermal heating, gives a broad asymmetrical distribution of fragments in agreement with a random process, whereas the entire silver fractal pearling fragmentation is driven by chemical adjunction of the surfactant.

Dynamics of polymorphic nanostructures: from growth to collapse.

The deposition of preformed clusters on surfaces offers new possibilities to build complex artificial nanostructures, the shape of which depends on the cluster size. We describe routes for generating unusual polymorphic nanoislands, which constitute unique platforms for exploring instabilities. As coverage increases, the constraints accumulated in such nanostructures induce spectacular flattening collapse processes, which are not observed when the constraints are imposed by the substrate.