Molecular Dynamics Simulation of Conformational Rearrangements in Polyelectrolyte Macromolecules on the Surface of a Charged or Polarized Prolate Spheroidal Metal Nanoparticle

摘要

Molecular dynamics simulation has been employed to study rearrangements in the conformational structure of polyelectrolytic polypeptides adsorbed on the surface of a charged prolate spheroidal gold nanoparticle, as well as such nanoparticle polarized along its major axis. An analytical model has been proposed for the structure of a Gaussian macrochain adsorbed on the spheroidal nanoparticle. The model reflects the features of the structure formation of the adsorbed macrochain in relation to the geometry of the uncharged and unpolarized prolate spheroidal nanoparticle. When necessary, it takes into account the surface charge or polarization of the particle by means of introducing the Boltzmann factor for equilibrium configurations of the macrochain in a potential field. Polyampholitic polypeptides adsorbed on the surface of the polarized prolate metal nanospheroid are swollen in the polar regions, while the units of uniformly charged polypeptides are shifted to the polar regions charged oppositely to the charge of the units. Being adsorbed on the surface of a charged prolate spheroidal gold nanoparticle, a polyelectrolyte macromolecule envelopes the entire nanoparticle and swells with an increase in the total charge of the nanospheroid.