Research in my lab is biophysical in nature – essentially using physical and chemical techniques to answer biological questions about the cell membrane, the selectively permeable structure that separates a cell’s interior from its surroundings. This structure serves many purposes ranging from functioning as a filter to control the flow of material into and out of the cell to serving as a recognition site by containing transmembrane proteins that trigger biochemical events within cells. The membrane is composed of a phospholipid bilayer; our lab uses several model systems to study basic intermolecular interactions between the phospholipids contained in the layer, as well as the effects of other relevant biomolecules. Two-dimensional lipid monolayers at the air/water interface are models of the outer leaflet of the cell membrane and allow control over composition and surface density of the biological components. In addition to monolayers, we create and image with fluorescence microscopy more physiologically relevant giant unilamellar vesicles, essentially spherical lipid bilayers that model a cell membrane without any cellular contents. With access to several cell membrane models and a variety of biophysical techniques, current projects in Lipid lab focus on measuring interactions of exogenous biological agents (nanoparticles, huntingtin protein and frog spit are examples) with the cell membrane – including how the agent affects the membrane and how the membrane affects the agent.
EY Chi, SL Frey, A Winans, KLH Lam, K Kjaer, J Majewski, and KYC Lee. Amyloid-beta fibrillogenesis seeded by interface-induced peptide misfolding and self-assembly. Biophysical Journal, 98 (2010) 2290-2298.
SL Frey, L Pocivavsek, AJ Waring, FJ Walther, JM Hernandez-Juviel, P Ruchala, and KYC Lee. The functional importance of N-terminal insertion sequence of lung surfactant protein, SP-B. American Journal of Physiology – Lung Cellular and Molecular Physiology, 298 (2010) L335-L347.
MK Ratajczak, EY Chi, SL Frey, KD Cao, L Hawk, J Majewski, K Kjaer, and KYC Lee. Ordered nanoclusters in lipid:cholesterol membranes. Physical Review Letters, 103 (2009) 028103.
L Pocivavsek, SL Frey, K Krishan, K Gavrilov, P Ruchala, AJ Waring, FJ Walther, M Dennin, TA Witten and KYC Lee. Lateral Stress Relaxation and Collapse in Lipid Monolayers. Soft Matter, 4 (2008) 2019-2029.