Fluorescence spectra decomposition by asymmetric functions: Laurdan spectrum revisited
Fluorescence spectra decomposition by asymmetric functions: Laurdan spectrum revisited
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DOI：
10.1016/j.ab.2013.05.031
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发表时间：
2013-09-15
影响因子：
2.9
通讯作者：
Radu, Mihai
中科院分区：
文献类型：
--
作者：
Bacalum, Mihaela;Zorila, Bogdan;Radu, Mihai
由于分子的不对称性质，用对数正态分布比用高斯分布能更好地分析分子的复杂荧光光谱。迄今为止，对数正态函数已被用于色氨酸和普罗丹等不同荧光分子的发射光谱反卷积，但据我们所知，对数正态函数用于劳丹（2-二甲氨基-6-劳丹萘）的反卷积要少得多。在这篇文章中，我们提出了分解Laurdan发射光谱在大单层囊泡使用的程序，依赖于对数正态不对称函数。该方法在不同溶剂的均相溶液中使用劳丹光谱进行校准。将我们的结果与高斯拟合得到的结果进行比较，我们发现(i)基本峰的位置（类似于440和490 nm）在包括脂质双分子层主要相变的大温度范围内保持不变；（ii）正如Laurdan所报道的那样，双分子层水合作用从凝胶相到液晶相增加了大约8倍，这一结果与其他报告相吻合，提供了更真实的描述。此外，我们提出了一个新的参数来全局评价Laurdan发射光谱，以期获得比经典的“广义极化”更大的取值范围。(C) 2013爱思唯尔公司版权所有。
Due to their asymmetric nature, complex fluorescence spectra of molecules can be analyzed much better by log-normal distributions than by Gaussian ones. So far, the log-normal function has been used for deconvolution of emission spectra of different fluorescent molecules, such as Tryptophan and Prodan, but to our knowledge it is far less used for Laurdan (2-dimethylamino-6-lauroylnaphthalene). In this article, we present the decomposition of Laurdan emission spectra in large unilamellar vesicles using a procedure that relies on the log-normal asymmetric function. The procedure was calibrated using Laurdan spectra in homogeneous solutions of various solvents. Comparing our results with the ones obtained from a Gaussian fit, we show that (i) the position of the elementary peaks (similar to 440 and 490 nm) is preserved in a large range of temperatures that include the main phase transition of lipid bilayer and (ii) the bilayer hydration, as reported by Laurdan, increases approximately 8 times from the gel phase to the liquid crystalline one, a result that fits with other reports, providing a more realistic description. In addition, we propose a new parameter to globally evaluate Laurdan emission spectra with the prospect of acquiring a larger range of values than the classical "generalized polarization". (C) 2013 Elsevier Inc. All rights reserved.