(Lecture, Jan 5) “Small Angle Scattering for Nanostructural Characterization ”and“Defects on Biomembrane Enhance Spontaneous Lipid Transfer Rate and Hydrophobic Interactions ”
time: 2018-01-04

Topic:  “Small Angle Scattering for Nanostructural Characterization ” and “Defects on Biomembrane Enhance Spontaneous Lipid Transfer Rate and Hydrophobic Interactions ”
Speaker: Assoc. Prof. Mu-Ping Nieh, University of Connecticut
Time: 15:00, Jan 5, 2018
Venue: Room 502, Building of State Key Laboratory of Luminescent Materials and Devices, Wushan Campus
Abstract:

1.Two most common available techniques of nanostructural characterization are microscopy and scattering and they are complementary to each other. The former ones provide direct and visual information in the real space, yet suffer from limited sampling. The latter ones yield global (average)  structure of the materials in the reciprocal space and thus require interpretation of the data. One the scattering techniques, small angle scattering (SAS) has been developed for decades to resolve structures of non-crystalline materials and has become more and more mature for material characterization. In this talk, I will introduce the basic principle of scattering, compare the functions of different probes (i.e., neutron, light, X-ray) used in SAS and demonstrate how SAS can be uniquely applied to various scientific topics.
2.Molecules, e.g., proteins, glycolipids, cholesterol, etc. have attracted enormous attentions because they control the activities on the biomembranes. There are hundreds of natural or synthetic phospholipids which differ in regards to the properties of hydrophilic headgroups (i.e., charge density and size) and hydrophobic acyl chains (e.g., number, length and level of saturation of the hydrocarbons). These differences vary the molecular spontaneous curvature, hydration, miscibility, solubility and crystallinity of the lipid molecules, resulting in segregation of lipids on the bilayer and/or formation of special morphology. Recently, a model lipid mixture composed of long- and short- chain lipids forming well-defined nanodiscs, which is also known as bicelle, has been investigated extensively in the biochemical and biophysical field. The rim of nanodiscs can be considered as “defects” on the model membrane. In this presentation, I will illustrate how these defects affect the lipid transfer kinetics and lipid interactions with foreign amphiphilic molecules, hoping to provide some fundamental insights into the activities associated with biomembranes.