Molecular rheometry: direct determination of viscosity in Lo and Ld lipid phases via fluorescence lifetime imaging

0394499 - ÚFCH JH 2014 RIV GB eng J - Journal Article
Wu, Y. - Štefl, Martin - Olžyńska, Agnieszka - Hof, Martin - Yahioglu, G. - Yip, P. - Casey, D. R. - Ces, O. - Humpolíčková, Jana - Kuimova, M. K.
Molecular rheometry: direct determination of viscosity in Lo and Ld lipid phases via fluorescence lifetime imaging.
Physical Chemistry Chemical Physics. Roč. 15, č. 36 (2013), s. 14986-14993. ISSN 1463-9076. E-ISSN 1463-9084
R&D Projects: GA ČR GBP208/12/G016; GA MŠMT LH13259
Institutional support: RVO:61388955
Keywords : CORRELATION SPECTROSCOPY * MODEL MEMBRANES * LIVE CELLS
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 4.198, year: 2013

Understanding of cellular regulatory pathways that involve lipid membranes requires the detailed knowledge of their physical state and structure. However, mapping the viscosity and diffusion in the membranes of complex composition is currently a non-trivial technical challenge. We report fluorescence lifetime spectroscopy and imaging (FLIM) of a meso-substituted BODIPY molecular rotor localised in the leaflet of model membranes of various lipid compositions. We prepare large and giant unilamellar vesicles (LUVs and GUVs) containing phosphatidylcholine (PC) lipids and demonstrate that recording the fluorescence lifetime of the rotor allows us to directly detect the viscosity of the membrane leaflet and to monitor the influence of cholesterol on membrane viscosity in binary and ternary lipid mixtures. In phase-separated 1,2-dioleoyl-sn-glycero-3-phosphocholine-cholesterol–sphingomyelin GUVs we visualise individual liquid ordered (Lo) and liquid disordered (Ld) domains using FLIM and assign specific microscopic viscosities to each domain. Our study showcases the power of FLIM with molecular rotors to image microviscosity of heterogeneous microenvironments in complex biological systems, including membrane-localised lipid rafts.
Permanent Link: http://hdl.handle.net/11104/0222737