(687b) Diffusion Characteristics of a Supported Lipid Bilayer Membrane On a Dense Cylindrical Silica Optical Fibrous Support

Cellular membranes are the key building blocks for biological sustainability. It is essential to understand their function and capabilities in order to gain a higher fundamental understanding of their critical properties. Lipid bilayer membranes are excellent models for cellular membranes, especially when incorporated with additional biological molecules, such as molecular receptors or protein ion channels, to study molecular binding within the biological membrane and molecular transport across the membrane, respectively. High quality cellular mimics are critical to ensure that the behavior observed in the artificial lipid bilayer membranes closely parallels the behavior observed in cellular membranes. Lipid bilayer membrane quality is typically measured using the fluorescence recovery after photobleaching (FRAP) confocal technique. Using this technique, the continuity and general mobility of the supported biomimetic membrane can be studied. Typically, lipid bilayer membranes are supported using planar supports of various surface chemistries. Little research has investigated lipid bilayer membrane diffusion behavior using other support geometries, such as a cylindrical support.

Within this work, the support used was a Corning SMF-28 dense silica optical fiber with a 125micrometer outer diameter. Lipid bilayer membranes were synthesized using the vesicle deposition technique. The average vesicle diameter was measured to be 100nm (dynamic light scattering) and the vesicles were verified to be structurally unilamellar (transmission electron microscopy). Using the FRAP technique, the fluidity and continuity of the lipid bilayer membranes were measured. The average diffusion coefficient of this tagged lipid system (eggPC lipids tagged with NBD-PE) in a planar configuration was 1.2 micrometers.s1. Various bleaching configurations were explored to determine if the observed membrane diffusivity was affected by the support geometry. Experiments verified that the measurement position on the fiber surface significantly affected the diffusion coefficient observed using confocal microscopy due to differing diffusion mechanisms across the supported lipid bilayer membrane.