INTELLECTUAL MERIT: The complex and multi-component plasma cell membrane provides inspiration for advances in nanotechnology and the development of new materials. In the past decade, consensus has grown around the importance of cholesterol for supramolecular lateral organization within this system. Today, cholesterol is recognized as crucial in the lateral organization of these membranes in both in vitro (lipid monolayers and bilayers) and in vivo (plasma cell membrane) systems. In Langmuir monolayers containing cholesterol and phospholipids the observed phase separation has been shown to be the result of a competition between long-range electrostatic forces and line tension in two dimensions. However, important questions remain regarding the true equilibrium nature of these systems, the size distribution of their domains, and the role of cholesterol's molecular structure in the observed phase separation. This project will test the hypothesis that the morphology of phase separated lipid monolayers containing cholesterol can be controlled by transition kinetics, monolayer composition, and sterol structure to enable the patterning of solid substrates. Motivation to control lipid membrane patterning comes from the applications of self-assembled lipid systems to the fabrication of biosensors and other biomaterials. Lipid monolayers are regularly used in the fabrication of supported lipid bilayers on solid substrates. Additionally, this project will explore the use of phase separated lipid monolayers to organize nanoparticles at the air-water interface. Through collaborations and partnerships this project will extend recently developed techniques in model convolution microscopy, new line tension measurement methods, and incorporate a novel micro-fluidic flow cell into a traditional fluorescence microscopy set-up.
BROADER IMPACTS: The scientific objectives of this project will be achieved within the context of research at a primarily undergraduate institution. Providing high quality research experiences to train and encourage undergraduates from diverse backgrounds to pursue careers in science, technology, engineering, and mathematics has been a central component of the principal investigator's role as an educator and mentor over the past seven years. Consistent with the demographics of Augsburg College, the principal investigator will continue to encourage and recruit participation from NSF-defined underrepresented populations. In addition to close faculty interactions through research, this project will provide students with opportunities to develop their understanding of vocational and career objectives through regular contact with collaborators and practicing scientists. The principal investigator will leverage Augsburg's Office of Undergraduate Research and Graduate Opportunities (URGO) to supplement these experiences through professional training as well as assistance in the application process for fellowships and graduate school. Weekly group meetings provide students with opportunities to build communication skills and confidence. Students will participate in the dissemination of results through presentations at regional and national conferences as well as co-authorship of on peer-reviewed publications. This project will also enrich the undergraduate curriculum at Augsburg College. Fluorescence microscopy and image analysis techniques used in this research will be incorporated into undergraduate laboratory experiences for physics majors in sophomore and senior level courses.
