Molecular Simulation Studies of Lipid Bilayers and Biomolecular Coatings for Water Barrier and Biocompatibility Purposes
Yang, Alexander Hao
Lipid bilayers occupying the gel and fluid phases are examined using molecular dynamics simulation. Molecular dynamics simulations of gel-phase bilayers comprised of varying compositions of distearoylphosphatidylcholine, saturated alcohol, and saturated fatty acid components are examined to study composition-structure relationships. Permeability calculations are performed to relate water barrier properties to gel-phase composition and structure. The results suggest equi-length components with small head groups enable high chain ordering and chain packing, thus prohibiting water permeation. Molecular dynamics simulations of fluid-phase bilayers comprised of dioleoylphosphatidylcholine and cholesterol in addition to graphene nanoflakes are performed to study the influence of graphene nanoflakes on fluid-phase bilayer structure. Biomolecular coatings including single-stranded DNA are also examined to observe any influence of graphene cytotoxic behavior. The results suggest graphene nanoflakes insert into lipid bilayers and compromise bilayer structure; on the other hand, adding biomolecular coatings still allows insertion while preserving bilayer structure. These results shed light on developing topical formulations to provide water barrier function to mitigate dry skin and developing biocompatible graphene applications to lipid bilayers.