Fluorescence in colloidal solutions: Scattering vs physicochemical effects on line shape
Fluorescence in colloidal solutions: Scattering vs physicochemical effects on line shape
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DOI：
10.1016/j.saa.2023.122356
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发表时间：
2023-01-13
影响因子：
4.4
通讯作者：
Boulesbaa，Abdelaziz
中科院分区：
文献类型：
--
作者：
Ranganathan，Radha;Munoz，Luis Manuel Davila;Boulesbaa，Abdelaziz
研究了阴离子荧光素在聚苯乙烯纳米颗粒、阴离子和阳离子胶束、脂质囊泡以及月桂醇在脂质囊泡中的荧光光谱。计算出的测量光谱的二次谐波表明荧光素的三条线和两个劳丹。因此，荧光素光谱拟合三个高斯和劳登光谱两个对数正态分布。针对颗粒浓度检查解析的线参数。散射，虽然波长依赖，影响强度，但不影响线形。散射对线形状的内部滤波器效应是微不足道的，因为多次散射、散射光子重定向到检测器中以及在收集和检测中包含散射光子最小化了波长相关效应。对线宽和峰位置的主要影响是由于染料-颗粒-溶剂相互作用的物理化学效应，而不是散射。黄绿素不与阴离子胶束和脂质囊泡相互作用，但保留在水相中，并响应由这些添加剂诱导的pH增加。在这些体系中，与在NaOH溶液中一样，峰位蓝移，线宽减小，发射强度增加。黄绿素确实与阳离子胶束和疏水性PSNP相互作用，并且其发射红移。脂质囊泡中的劳丹感知界面极性。其发射线的蓝移和线宽的减小表明极性随脂质浓度而减小。散射以及相互作用影响发射强度。物理化学效应使谱线变形并改变本征光谱。线形状变化是比强度更好的标记，以研究相互作用和反应。
Line shapes of anionic fluorescein fluorescence in suspensions of polystyrene nanoparticles (PSNP), anionic and cationic micelles, lipid vesicles, and of laurdan in lipid vesicles were investigated. Computed second harmonic of measured spectra indicated three lines for fluorescein and two for laurdan. Accordingly, fluorescein spectra were fit to three Gaussians and laurdan spectra to two lognormal distributions. Resolved line parameters were examined against particle concentration. Scattering, although wavelength dependent, affected intensity but not line shape. Inner filter effects of scattering on line shape are insignificant because multiple scattering, redirection of scattered photons into the detector, and inclusion of scattered photons in collection and detection minimize wavelength dependent effects. Dominant effects on line width and peak positions are due to physicochemical effects of dye-particle-solvent interactions rather than scattering. Fluorescein does not interact with anionic micelles and lipid vesicles, but remains in the aqueous phase, and responds to pH increase induced by these additives. Blue shift in peak position, decrease in line width, and increase in emission intensity in these systems are like those in NaOH solutions. Fluorescein does interact with cationic micelles and hydrophobic PSNP, and its emission is red shifted. Laurdan in lipid vesicles senses interface polarity. Blue shift and decrease in line width of its emission line indicate decreasing polarity with lipid concentration. Scattering, as well as interactions affect emission intensity. Physicochemical effects distort line shape and modify intrinsic spectra. Line shape changes are better markers than intensity to investigate interactions and reactions.