2005 Ohio Student Research Forum

Abstract

Novel Fluorophores as Viscosity Dependent Probes of Biological Molecules
Shamere Ashley
Kent State University, Department of Biochemistry
Mentor: Dr. Arne Gericke

Biological membranes are fluid e.g., a slightly higher order than the surrounding membrane, lipid bilayers. These bilayers contain regions that have different physical properties called domains or rafts. Rafts are in a liquid-ordered state and are sites for specific physiological functions in the cell. Fluorescently labeled lipids are widely used to highlight domains and to visualize them with techniques like confocal microscopy. We have investigated molecules that show a viscosity dependent fluorescence and therefore, they can be used to distinguish between domains of different order such as gel-ordered DPPC (dioleoylphosphatidylcholine), or fluid DOPC (dipalmitoylphophatidylcholine) and POPC (1-palmitoyl-2-oleophosphatidylcholine). Samples were made with a 0.1% molar concentration of fluorophore to lipid mixture. Increased viscosity resulted in a higher emission wavelength, i.e. DPPC resulted in a higher emission wavelength than DOPC and POPC, indicating that it has a higher ordered state.