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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:56 |
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Conference: Bucharest University Faculty of Physics 2013 Meeting
Section: Biophysics; Medical Physics
Title:
A new method for analyzing the elementary, simulated and measured complex spectra of Laurdan
Authors:
Bogdan Zorila, Mihaela Bacalum, Mihai Radu
Affiliation:
Department of Life and Environmental Physics, Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele, PO Box MG-6, 077125, Romania
E-mail
bzorila@nipne.ro
Keywords:
Laurdan, complex emission spectrum, log-normal function, bilayer state of hydration, bilayer fluidity
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) [1,2,3], but less for Laurdan. In this paper we present a procedure for analyzing the complex spectra of Laurdan with the help of log-normal function, calibrated for Laurdan by analyzing his elementary fluorescence spectra in solvents [4]. Along with the calibration procedure and algorithm of decomposition of complex spectra, are also analyzed some complex fluorescence spectra of Laurdan (generated taking into account the assumptions made in the calibration procedure) and a few spectra of Laurdan, used for the purpose it was designed, in particular, as an indicator sample for the state of hydration or fluidity of lipid bilayer of cell membrane (model membranes in our study). 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) [5].
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