Heterogeneous rotational diffusion of a fluorescent probe in lipid monolayers

Neda Dadashvand; LaNell A Williams; Christina M Othon

doi:10.1063/1.4894379

Heterogeneous rotational diffusion of a fluorescent probe in lipid monolayers

Struct Dyn. 2014 Aug 27;1(5):054701. doi: 10.1063/1.4894379. eCollection 2014 Sep.

Authors

Neda Dadashvand¹, LaNell A Williams¹, Christina M Othon¹

Affiliation

¹ Physics Department, Wesleyan University , Middletown, Connecticut 06459, USA.

Abstract

The rotational correlation time of the lipid probe 1-palmitoyl-2-{6-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]hexanoyl}-sn-glycero-3-phosphocholine (NBD-PC) is measured using fluorescence anisotropy for two lipid species. We measure the rotational diffusion in a monolayer of 1,2-Didecanoyl-sn-glycero-3-phosphocholine (DPPC) which displays a phase transition at room temperature from the liquid-expanded to the liquid-condensed phase. The constant rotational diffusion of the probe throughout the phase transition reflects the measurement of dynamics in only the liquid-expanded phase. We contrast the dynamic changes during this phase coexistence to the continuous density increase observed in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) at room temperature. We observe a non-exponential decay of the probe diffusion consistent with heterogeneity of the orientational dynamics.