A multiscale approach to study molecular and interfacial characteristics of vesicles

Abstract

The functions of colloids, such as membranes and vesicles, are dictated by interfacial properties which are determined by an interplay of physical interactions and processes spanning multiple spatiotemporal scales. The multiscale characteristics of membranes and vesicles can be resolved by the hybrid molecular dynamics-lattice Boltzmann technique. This technique enables the resolution of particle dynamics along with long range electrostatic and hydrodynamic interactions. We have examined the feasibility of an implementation of the hybrid technique in conjunction with a Martini-based implicit solvent coarse-grained force field to capture the molecular and interfacial characteristics of membranes and vesicles. For simplicity, we have examined two types of vesicles whose molecular components have different sustained interactions with the solvent. One of the vesicles encompassed phospholipids and the other vesicle was composed of phospholipids and poly ethylene glycol (PEG)-grafted lipids. The molecular and interfacial characteristics of the phospholipid vesicle and PEGylated, or hairy, vesicles are found to be in good agreement with earlier experimental, computational and theoretical findings. These results demonstrate that the multiscale hybrid technique used with a Martini-based implicit solvent coarse-grained model is suitable for capturing the molecular and interfacial characteristics of membranes and vesicles. Furthermore, other implicit solvent coarse-grained models can be used in conjunction with the hybrid molecular dynamics-lattice Boltzmann technique to examine the molecular and interfacial characteristics of membranes and vesicles. Our study demonstrates the potential of the hybrid technique in capturing multiscale interfacial characteristics of intra- and inter-colloid interactions in suspensions under different flow conditions, and their relation to molecular properties. In addition, this technique can be applied to design colloids with multiscale characteristics which yield desired interactions with other colloids and responses to external stimuli.