Interactions in Elastically- Responsive Composite Lipid Vesicles

Giant unilamellar lipid vesicles are often studied because they provide insights to cellular behavior; however, when they contain solid membrane domains they also serve as models for two-dimensional colloidal suspensions.  These new materials can form the basis for an innovative nanotechnological platform for targeted delivery and energy storage. Our work explores the experimental methods to produce lipid vesicles with limited numbers (1,2 or 3) of regular domains and focuses on the interaction potentials between these domains.  We also probe the reversible multibody interactions and assembly of micron-scale domains in phospholipid vesicles through the manipulation of membrane curvature by osmotic adjustment or mechanical manipulations using micropipettes. The observations in inter-domain positions suggest the existence of long-range interdomain attractions and short-range interdomain repulsions resulting from the shear elasticity of the solid domain. This discovery suggests a new picture that allows tunable interactions to form sophisticated responsive patterns on 2D fluid materials.