Imaging and Reaction Dynamics in Model Biological Membranes: Soft Nanoscience
Our lab has developed a wide range of methods for patterning lipid bilayers on solid supports. These 2D fluids are interesting as a model for biological membranes, as a physical system with unusual properties, and as a step towards the creation of controlled interfaces between biological and non-biological surfaces. Methods have been developed for controlling the composition of patterned membrane corrals by variations on microcontact printing and microfluidics. Charged components can be moved around within these fluid surfaces by a form of 2D electrophoresis. Although this is a model membrane system, it provides an excellent platform for the development of advanced imaging and analysis methods, and components displayed in the supported bilayer model membrane can interact with and affect the function of native cell membranes. Fluid planar lipid bilayers can be used as a platform to tether small vesicles by short complimentary DNA sequences added as lipid head groups. Once tethered, vesicles are laterally mobile in the plane of the supported bilayer, so individual vesicle-vesicle interactions, including vesicle fusion, mediated by different components on the vesicle surface or in solution, can be observed directly. Because this is a completely synthetic system and the DNA sequence, length, spacer length and the nature of the membrane anchors can be controlled, this is an attractive system for systematic investigation of the requirements for vesicle docking and fusion. The DNA-lipid approach can also be used to create architectures of increasing complexity that begin to mimic many of the properties of real cell membranes. The planar geometry of the supported bilayer systems is also ideal for surface sensitive imaging methods including interferometry and imaging mass spectrometry . 报告邀请人：李明 研究员 (82649058)
Steven G. Boxer
Camille and Henry Dreyfus Professor of Chemistry Department of Chemistry, Stanford University
My research group investigates structure and function in biological systems from a physical perspective. We exploit and extend many different physical methods, both experimental and theoretical, and combine these with the tools of modern molecular biology, protein engineering, synthetic chemistry and self-assembly. Part of my lab investigates electrostatics and dynamics in proteins. Systems under investigation include excited state electron and energy transfer in photosynthetic reaction centers, excited state dynamics in green fluorescent protein, and electrostatics at the active sites of several enzymes probed using vibrational Stark spectroscopy. In each case, we focus on what is unique about the organized environment found in proteins or assemblies of proteins and attempt to make a quantitative connection with models for these systems. A second area of my lab develops novel membrane architectures as a basis for studying many areas of membrane biophysics. This will be the area described in my seminar – the abstract follows.