Lipid Diffusion in Supported Lipid Bilayers: A Comparison between Line-Scanning Fluorescence Correlation Spectroscopy and Single-Particle Tracking

Membranes

Markus Rose¹  Nehad Hirmiz¹  Jose M. Moran-Mirabal²  Cຜile Fradin¹ 

[1] Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; E-Mails:;Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4L8, Canada

关键词: lipid;    bilayer;    membrane;    diffusion;    fluorescence;    confocal microscopy;    total internal reflection fluorescence microscopy (TIRF);    FCS;    SPT;   

DOI  :  10.3390/membranes5040702

来源: mdpi

【 摘 要 】

Diffusion in lipid membranes is an essential component of many cellular process and fluorescence a method of choice to study membrane dynamics. The goal of this work was to directly compare two common fluorescence methods, line-scanning fluorescence correlation spectroscopy and single-particle tracking, to observe the diffusion of a fluorescent lipophilic dye, DiD, in a complex five-component mitochondria-like solid-supported lipid bilayer. We measured diffusion coefficients of D_FCS ~ 3 μm² · s⁻¹ and D_SPT ~ 2 μm² · s⁻¹, respectively. These comparable, yet statistically different values are used to highlight the main message of the paper, namely that the two considered methods give access to distinctly different dynamic ranges: D ≳ 1 μm² · s⁻¹ for FCS and D ≲ 5 μm² · s⁻¹ for SPT (with standard imaging conditions). In the context of membrane diffusion, this means that FCS allows studying lipid diffusion in fluid membranes, as well as the diffusion of loosely-bound proteins hovering above the membrane. SPT, on the other hand, is ideal to study the motions of membrane-inserted proteins, especially those presenting different conformations, but only allows studying lipid diffusion in relatively viscous membranes, such as supported lipid bilayers and cell membranes.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.