Modeling of Conformational Changes of Polyelectrolytes on the Surface of a Transversely Polarized Metal Nanowire in an External Electric Field

Abstract

Gold nanowires with polyelectrolytes adsorbed on their surface are widely used in various biomedical research. In this work, for the first time, conformationalchanges in polyelectrolytes on the surface of a gold nanowire transversely polarized in an external electric field were considered. The properties of a specially created analytical model of conformational rearrangements of a Gaussian macromolecular chain adsorbed on the surface of a cylindrical metal nanowire in an external electric field transverse to the axis of the nanowire were investigated. Conformational changes of uniformly charged polypeptides on the surface of a transversely polarized gold nanowire have been studied using molecular dynamics simulation. On the basis of the analytical model and the results of molecular dynamics simulation, the spatial distributions of the density of polyelectrolyte units on the surface of the nanowire were constructed. With an increase in the strength of the external electric field, an asymmetric stretching of the polyelectrolyte fringe in the direction of the dipole moment of the transversely polarized nanowire was observed.

Conformational Structure of an Adsorbed Polyelectrolyte on a Nanoparticle With Low Conductivity in an Alternating Electric Field

“…The conformational function ()  r , which depends on the radius vector r of a chain link and takes into account the entropy factor for the formation of the bulk structure of a macromolecule, can be calculated on the basis of a specialized differential equation [23], which was previously done in the case of a short-range adsorbing potential [17,19]. When applying an external, harmonically changing electric field 0 exp( )…”

“…In this case, at the positively charged pole of the nanoparticle, the atoms acquired partial charges induced by the electric field equal approximately to +0.1e, +0.2e, and +0.4e. In the case of static polarization of a germanium nanoparticle, MD simulation was performed at a constant temperature (Berendsen thermostat) at 900 K followed by a decrease to 300 K. This made it possible to reach deeper minima of the conformational energy of the macrochain, including in a shorter section of the trajectory [14,[17][18][19][20]. At the same time, to control the obtaining of equilibrium conformations, the change in the mean square distance between polypeptide atoms in different conformations (RMSD) was monitored.…”

“…Previously, in [14][15][16][17][18][19][20][21], conformational changes in polyampholytic polypeptides adsorbed on the surface of gold nanoparticles of various shapes (spherical, cylindrical, and spheroidal) were studied under the influence of both a static and an alternating microwave electric field. It was shown that the shape of a metal nanoobject significantly affects the conformations of adsorbed polyampholytes.…”

Molecular dynamics simulation of the rearrangement of polyampholyte conformations on the surface of a charged oblate metal nanospheroid in a microwave electric field

“…In the case of adsorption of polyelectrolyte macromolecules on a charged metal surface, under the influence of electric charges distributed over the metal surface, the conformational structure of the adsorbed macrochain is rearranged. In this case, the conformational changes in the adsorbed polyelectrolyte are affected by the shape of the metal nanoobject and the distribution of the surface density of electric charges on it [22][23][24][25][26][27][28]. The conformational structure of a macromolecule adsorbed on a nanoparticle is also significantly affected by the distribution order of charged units in the macrochain.…”

“…The conformational structure of a macromolecule adsorbed on a nanoparticle is also significantly affected by the distribution order of charged units in the macrochain. Thus, for generally neutral polyampholyte macromolecules and uniformly charged polyelectrolytes, the character of changes in their conformations during adsorption on the surface of metal nanoparticles charged or polarized in an external electric field is very different [22][23][24][25][26][27][28].…”