This award by the Biomaterials Program in the Division of Materials Research to State University of New York at Stony Brook is to study membranes of living cells composed of lipids (specialized fat molecules) and proteins. Membranes control the uptake of food stuffs into cells and the communication between cells and their environment. Cell membranes are very complex, consisting of thousands of types of different proteins and lipids. Artificial membrane vesicles, composed of membrane lipids and proteins which are forming an envelope similar to a cell membrane, are important tools in understanding how membranes function. Natural membranes have two layers of membrane lipids, and they are asymmetric with different types of lipids in each layer. A key limitation in the utility of artificial membranes has been their lack of lipid asymmetry. Investigators of this award earlier discovered a method to prepare asymmetric artificial membranes. The proposed research on artificial membranes is expected to greatly expand the scientific knowledge on membranes. Additionally, this project will also have a broad impact on career development of future scientists, including minority students, by training both graduate and undergraduate students (including via contacts with other local institutions) in the conduct of research, experimental principles, and experimental techniques used in membrane research. Students will also be trained in proper conduct of scientific studies, scientific writing and speaking, which will prepare them for careers in research, teaching, or allied fields.
Lipid asymmetry, a difference in the lipid composition in the inner and outer leaflets (monolayers) of a biological membrane, is a crucial property of the lipid bilayer in many cell membranes. Artificial vesicles (liposomes) containing lipid bilayers are biomaterials that have proven invaluable models of biological membranes, but the lack of methods to prepare asymmetric vesicles has limited their utility. With this grant, the first goal will be to prepare vesicles with inside-out asymmetry (cytosolic lipids facing outwards); to prepare vesicles containing a wide variety of outer leaflet lipids; and to prepare artificial asymmetric fungal membranes and bacterial outer membranes. The second goal will be to incorporate membrane proteins into asymmetric vesicles. The third goal will be to use asymmetric vesicles to tackle the biologically important issue of coupling between inner and outer leaflet physical properties. Such coupling has been proposed to contribute to signal transduction across biomembranes. To better understand the coupling between the outer and inner layers and signal transactions between them, fluorescent and neutron scattering studies will be carried out in collaboration with scientists at Oak Ridge National Laboratory. Additionally, this project will have a broad educational impact on career development of future scientists, including minority students, by training both graduate and undergraduate students (including via contacts with other local institutions). Students will receive specialized training in a variety of biochemical and spectroscopic techniques used in this study of membrane proteins and lipids, including unique methods developed in this investigator's laboratory. Students will also be trained in proper conduct of scientific studies, and writing and speaking skills, preparing them for careers in field of biological/biophysical sciences and/or teaching. Finally, by developing improved model for membrane systems, this project should broadly impact the field of membrane biology, including drug delivery and nanomaterial applications.
