Influence of Artificial Periodicity and Ionic Strength in Molecular Dynamics Simulations of Charged Biomolecules Employing Lattice-Sum Methods

2004 ◽  
Vol 108 (2) ◽  
pp. 774-788 ◽  
Author(s):  
Mika A. Kastenholz ◽  
Philippe H. Hünenberger
Keyword(s):  
Molecular Dynamics ◽  
Ionic Strength ◽  
Molecular Dynamics Simulations ◽  
Lattice Sum ◽  
Dynamics Simulations

scholarly journals Dispersion state phase diagram of citrate-coated metallic nanoparticles in saline solutions

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian Franco-Ulloa ◽  
Giuseppina Tatulli ◽  
Sigbjørn Løland Bore ◽  
Mauro Moglianetti ◽  
Pier Paolo Pompa ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ionic Strength ◽  
Molecular Dynamics Simulations ◽  
Metal Nanoparticles ◽  
Metallic Nanoparticles ◽  
Free Energy Calculations ◽  
Coarse Grained ◽  
Solvent Accessible Surface Area ◽  
Dispersion State ◽  
Dynamics Simulations

Abstract The fundamental interactions underlying citrate-mediated chemical stability of metal nanoparticles, and their surface characteristics dictating particle dispersion/aggregation in aqueous solutions, are largely unclear. Here, we developed a theoretical model to estimate the stoichiometry of small, charged ligands (like citrate) chemisorbed onto spherical metallic nanoparticles and coupled it with atomistic molecular dynamics simulations to define the uncovered solvent-accessible surface area of the nanoparticle. Then, we integrated coarse-grained molecular dynamics simulations and two-body free energy calculations to define dispersion state phase diagrams for charged metal nanoparticles in a range of medium’s ionic strength, a known trigger for aggregation. Ultraviolet-visible spectroscopy experiments of citrate-capped nanocolloids validated our predictions and extended our results to nanoparticles up to 35 nm. Altogether, our results disclose a complex interplay between the particle size, its surface charge density, and the ionic strength of the medium, which ultimately clarifies how these variables impact colloidal stability.

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