(380e) Straining Membrane Vesicles and Cells in Aqueous Nematic Liquid Crystals

Understanding how biological assemblies deform in response to mechanical interactions is central to understanding the functions of many biological systems. In this presentation, we will describe how aqueous liquid crystals (LCs) provide the basis of novel approaches to measuring the mechanical properties of membrane vesicles and cells. First, we will report how cycles of thermally induced phase transitions between nematic and isotropic phases can be used to exert cyclical elastic stresses on giant unilamellar vesicles (GUVs) and thereby evolve their shapes and properties. We observe GUVs to form a range of complex shapes, including stomatocyte, pear- and dumbbell-like shapes that depend on the extent of strain in the LC phase. Second, we will report on the use of LC elastic stresses to provide insight into the mechanical properties of cell membrane-derived vesicles. Specifically, we will describe experimental results in which LCs are used to strain giant plasma membrane vesicles (GPMVs) blebbed from cells expressing the mucin Muc1. We will show how the extent of straining of GPMVs changes with the level of expression of Muc1 on their membranes. Finally, recent results obtained with the straining of red blood cells in LCs will be shown to provide insight into the extent of variation of the mechanical properties of cells within a population. Overall, these examples will illustrate the utility of aqueous LC phases as elastic liquids for straining a range of soft biological assemblies.