Adsorption isotherms of charged nanoparticles

Abstract

We present theory and simulations which allow us to quantitatively calculate the amount of surface adsorption excess of charged nanoparticles to a charged surface. The theory is very accurate for weakly charged nanoparticles and can be used at physiological concentrations of salt. We have also developed an efficient simulation algorithm which can be used for dilute suspensions of nanoparticles of any charge, even at very large salt concentrations. With the help of the new simulation method, we are able to efficiently calculate the adsorption isotherms of highly charged nanoparticles in suspensions containing multivalent ions, for which there are no accurate theoretical methods available.

The role of pH, metal ions and their hydroxides in charge reversal of protein-coated nanoparticles

“…Overcharging of pure proteins is usually explained by the adsorption of ions at proteins. 1,5,33,[50][51][52][53][54][55][56][57][58][59][60][61][62] However, this argumentation falls short, as the pre-and post-incubation pH has rarely been considered for Au@protein systems [63][64][65] or for pure proteins. 9,20 When the post incubation pH was measured, huge pH effects were observed that changed the protein charge drastically.…”

Silver-Protein Nanocomposites as Antimicrobial Agents

“…Atomic Force Microscopy (AFM 5600LS, Agilent, Santa Clara, California, USA) was used to provide 2-dimensional and 3-dimensional AFM of both AgNPs and either Ag-FNP and Ag-MNP. First, samples were subjected to ultrasound waves for one hour, a condition of 60 kHz, and an amplitude of 85% and 0.6 of a cycle (UP400S manufactured by Hielscher, Teltow, Germany); then, a thin film was created using a spin coating instrument model Laurell-650Sz under the condition of 820 rpm under vacuum [41].…”

“…Samples were degassed at 50 • C for 3 h. Nitrogen was the adsorbate model, with the following specifications: cross-sectional area (16.2 Å 2 /molec), molecular weight (28.0134 g), bath temperature (77.35 K), magnetic susceptibility (2 (mL/mol) × 10 −29 ), critical pressure (33.5 atm), critical temperature (126.2 K), and supercritical adsorption. In addition, the isotherm curves of AgNPs and Ag-protein nanocomposites were constructed as described by [41].…”

Ionic size effects on the Poisson-Boltzmann theory

“…How relevant these correlations will be depends on a fine tuning between ionic charge, size and the dielectric constant of the solvent they are embedded into 29 . The relative strength of electrostatic correlations can be quantified via the so-called coupling parameter [39][40][41][42] , which measures the ratio between the electrostatic energy at ionic contact and the ionic thermal energy. Even if the ions bear relatively large charges (e .g.…”

“…Quite recently, one such mPB has been designed by dos Santos et al 73 in order to account for finite size effects on the adsorption of charged hard nanoparticles at a charged interface.…”