Efficient Molecular Approach to Quantifying Solvent-Mediated Interactions

Abstract

The solvent-mediated interaction, or equivalently the depletion force, play a pivotal role in the processes, by which two objects in solution such as lock and key particles, antibody and antigen, macromolecule and substrate, are attracted to each other. The quantification of this interaction is important yet challenging since it depends on the microscopic solvent structure in the surrounding. Here, we report an efficient molecular approach for predicting the solvent-mediated interaction by combining the classical density functional theory with a reversible solvation thermodynamic circle. For demonstration, the solvent-mediated interactions between two nanoparticles and between a nanoparticle and a rough wall are examined, and good agreements compared with the simulation results are illustrated. This approach is thereafter employed to interpret the reported self-assembly phenomena of lock and key colloidal particles. We show that the binding probability between the lock and key colloids can be successfully characterized at different depletant concentrations and system temperatures. This approach provides a potential route for identifying the coarse-graining interaction between two objects in fluid systems.

A molecular model for ion dehydration in confined water

“…To further assess the interfacial effect, we calculate the nominal hydration free energy of water in the interfacial system. Different with the traditional hydration free energy which is defined with the solvent in free space, the nominal hydration free energy represents the reversible work to place the solute from gas phase into the an interfacial water system, and it indicates the hydration ability of the solute in the interfacial system. The nominal hydration free energy varying with the distance to the wall is shown in Figure b.…”

Thermodynamic Barrier for Nanoparticle Penetration into Nanotubes

“…CDFT offers an appealing method to predict the thermodynamic properties of inhomogeneous fluids, and it has been widely applied to investigate different confined systems, including fluid transport in nanopores . As demonstrated in our previous work, CDFT can be used to quantify the PMF between two objects in solution and give accurate predictions of the PMF between NPs and that between a single NP and a rough wall in HS solvent systems compared with simulation data. This approach is computationally simple and efficient, which is universal and suitable for the systems with either finite or infinitely low concentrations of the target component.…”

“…Jin and Wu proposed a simulation-based hybrid method for predicting the PMFs between a test particle and various concave objects in hard-sphere (HS) solvents, demonstrating an excellent agreement with direct simulation results. Upon the solvation free-energy calculation, we recently proposed an efficient theoretical approach based on the classical density functional theory (CDFT) for quantifying the PMFs of two objects in different HS solvents …”

The size-selective interaction of key and lock nanocrystals driven by depletion attraction at the nanoscale

“…Due to these complications, the investigations of feasible key-lock systems at the nanoscale were done mostly theoretically. [3][4][5][6][7] Only two experimental studies at the nanoscale have been published so far. George and co-workers prepared concave iron oxide nanoparticles by a cast-mold approach in 2011.…”

“…16 Although theoretical studies predict the key-lock interactions initiated via depletion interaction at the nanoscale, this driving force was never used experimentally for such a system so far. 3,4,7 In this paper, we show an experimental study of a novel key-lock system at the nanoscale. We design tailored lock particles consisting of concave-shaped manganese oxide nanocrystals prepared via a cast-mold approach.…”