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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:09 |
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Conference: Bucharest University Faculty of Physics 2014 Meeting
Section: Biophysics; Medical Physics
Title:
A study upon bilayer fluidity of different types of liposomes
Authors:
M. C. AVRAM(1), Mihaela BACALUM(2), B. ZORILA(1, 2) and Doina GAZDARU(1)
Affiliation:
1) Department of Electricity, Solid State and Biophysics, Faculty of Physics, University of Bucharest, Magurele, Romania
2) Department of Life and Environmental Physics, “Horia Hulubei” National Institute of Physics and Nuclear Engineering, Magurele, Romania
E-mail
avram_mihai18@yahoo.com
Keywords:
Liposomes, Laurdan fluorescence, generalised polarization,log-normal deconvolution, lipid membrane fluidity, phospholipid phase transition
Abstract:
Because of the asymmetric shape of elementary spectra of fluorophores, complex spectra of fluorescence (two or three peaks superimposed on the same graph) can be analyzed, in terms of populations of fluorescent species, much better with the log-normal distributions than by Gaussian ones. The log-normal function was used for analyzing the spectra from different fluorescent species (Prodan and Tryptophan), but less for Laurdan. This type of decomposition of complex fluorescence spectra reveals a more realistic model of hydration or fluidity of lipid bilayer than the analysis of fluorescent populations with the Gauss function and classical generalized polarization (GP).In this study, in this study we made an analysis of bilayer fluidity using deconvolution of complex fluorescence spectra of Laurdan inserted in different types of LUV’s (liposomes). The lipids used for preparation of liposomes was: 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and a mixture of DOPC:DPPC (20:80).Using the log-normal deconvolution procedure and the difference of relative areas of elementary peaks obtained after deconvolution: ∆Sr = SrB – SrG the fluidity of bilayer was estimated in comparison with classical generalized polarization (GP). The ∆Sr parameter, as was proved before, describe much better the state of bilayer.
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