(104e) Ordering Transitions Triggered By Specific Binding of Vesicles to Protein-Decorated Interfaces of Thermotropic Liquid Crystals

This presentation will address an investigation of the interactions of phospholipid vesicles with protein-decorated interfaces of thermotropic liquid crystals (LCs).  We have observed that following the capture of vesicles at a protein-decorated LC interface via specific binding interactions, phospholipids are transferred from the vesicles onto the LC interface to form a monolayer, partially displacing proteins from the LC interface and thereby triggering a continuous ordering transition in the LC.  The dynamics of this process are accelerated substantially by the specific binding event relative to a protein-decorated interface of a LC that does not bind the ligands presented by vesicles.  The observation of the continuous change in the ordering of the LC is significant as it is consistent with the presence of sub-optical domains of proteins and phospholipids on the LC interface.  An additional significant hypothesis that emerges from the work to be reported in this presentation is that the ordering transition of the LC is strongly impacted by the bound state of the protein adsorbed on the LC interface, as evidenced by the influence on the LC of (i) “crowding” of the protein within a monolayer formed at the LC interface and (ii) aging of the proteins on the LC interface.  Overall, these results demonstrate that ordering transitions in LCs can be used to provide fundamental insights into the competitive adsorption of proteins and lipids at oil-water interfaces, and that LC ordering transitions have the potential to be useful for reporting specific binding events involving vesicles and proteins.