Bimetallic Ag–Cu nanoparticles interaction with lipid and lipopolysaccharide membranes

Unique physical and chemical properties of bimetallic nanoparticles of immiscible metals attract the attention of researchers in various fields. Besides materials science and engineering sciences these nanoparticles (NPs) may also be of great practical importance in the biomedicine and the environmental science. Interaction of nanoparticles and nanomaterials with cell and bacterial membranes is a complex multi-factor problem, the solution of which provides an opportunity to predict some parameters of nanoparticles associated with their potential biological activity. This article is the first study of the bimetallic nanoparticles interaction with phospholipid and lipopolysaccharide (LPS) membranes using the molecular dynamics. The free energy change during the Ag-Cu nanoparticles adhesion to the biomembranes were estimated depending on the composition of the membrane and the nanoparticle. Using the force field based molecular dynamics it was shown that lipid membrane tends to wrap Ag-Cu NPs unlike LPS membrane. The presence of loose oxide film on the nanoparticle surface leads to a decrease of adhesive interaction between NP and biomembranes. Using the quantum mechanical calculation, the dependence of surface charge density of Ag-Cu NP on the nanoparticle composition were estimated. The result demonstrates the possibility of tuning the NP electrostatic properties, which, as known, determine the cellular uptake and cytotoxicity of nanomaterials. Most of the findings can be generalized to a case of bimetallic NPs of any pair of immiscible or partially miscible metals.