Coarse-grained hybrid simulation of liposomes

Abstract

We developed a new hybrid model for efficient modeling of complete vesicles with molecular detail. Combining elements of Brownian dynamics (BD) and dynamic density functional theory (DDFT), we reduce the computational load of an existing coarse grained particle-based dissipative particle dynamics (DPD) model by representing the solvent as a continuum variable or a field, in a consistent manner. Both particle and field representations are spatially unrestricted and there is no need to treat boundaries explicitly. We focus on developing a general framework for deriving the parameters in this hybrid approach from existing DPD representations, and validate this new method via a comparison to DPD results. In addition, we consider a few proof of principle calculations for large systems, including a vesicle of realistic dimensions (∼45 nm radius) containing (10⁴) lipids simulated for (10⁶) time steps, to illustrate the performance of the new method.