Surface sticking and lateral diffusion of lipids in supported bilayers.
The diffusion of fluorescently labeled lipids in supported bilayers is studied using two different methods: Z-scan fluorescence correlation spectroscopy (z-scan FCS) and two-focus fluorescence correlation spectroscopy (2f-FCS). It is found that the data can be fitted consistently only when taking into account partial sticking of the labeled lipids to the supporting glass surface. A kinetic reaction-diffusion model is developed and applied to the data. We find a very slow sticking rate which, however, when neglected, leads to strongly varying estimates of the free diffusion coefficient. The study reveals a strong sensitivity of FCS on even slight binding/unbinding kinetics of the labeled molecules, which has significance for related diffusion measurements in cellular lipid membranes.
Dertinger
Thomas
T
Institute for Biological Information Processing I, Forschungszentrum Jülich, D-52425 Jülich, Germany.
von der Hocht
Iris
I
Benda
Ales
A
Hof
Martin
M
Enderlein
Jörg
J
D004058:Diffusion; D008051:Lipid Bilayers / Q000737:chemistry*; D013499:Surface Properties
D008051:Lipid Bilayers