(63i) Replica Exchange Dynamic Molecular Simulations and Studies of Novel Cyclic and Linear Amphiphilic Homopolymer

Replica Exchange Dynamic Molecular simulations of Cyclic and Linear Amphiphilic Homopolymer

Lixin Liu, Henry S. Ashbaugh*, Steve W. Rick^*, Scott Grayson^*
Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA 70118

Abstract

Polymer-based micelles had been raised particular interests in application as drug delivery material because their spontaneously forming core-shell structure with hydrophobic core encapsulating solvent-compatible particles as long as hydrophilic corona imparting water-solubility upon the aggregation. In our research work, Molecular Dynamic (MD) simulations based on a novel Amphiphilic Homopolymer c-PHS-Amph first reported by Scott Grayson’s lab were performed to investigate polymer’s unique topologies as well as its resulting prominent solvent-dependent character, which would progressively shed a in-depth interpretation to the molecular driving force leading amphiphilic behavior.  Since Macromolecule requiring relative large scale computational work, we have cooperated with Steve Rick’s group to employ Replica Exchange Dynamic Simulation (REDs) to improve sampling space and determine the global polymer conformation. Through applying REDs technique, exchange among replicas split in large potential barriers occurred efficiently and successfully deliver linear and cyclic polymer’s characteristic structure corresponding with different solvents’ environment.  Proximal radial distribution of solvent around hydrophobic arms and hydrophilic arms was performed to validate the thermodynamic signatures as well as used to reproduce the density profile of interacting solvents.