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Abstract：
The study of surfactant and bio membranes interaction is particularly complex due to the diversity in lipid composition and the presence of proteins in natural membranes. Even more difficult is the study of this interaction in vivo since cellular damage may complicate the interpretation of the results, therefore for most of the studies in this field either artificial or model systems are used. One of the model system most used to study biomembranes are erythrocytes due to their relatively simple structure (they lack nuclei and organelles having only the plasma membrane), their convenient experimental manipulation and availability. In this context, we used rabbit erythrocytes as a model membrane and Laurdan (6-lauroyl-2-dimethylaminonaphthalene) as the fluorescent probe to study changes promoted in the membrane by the interaction with the sucrose monoester of myristic acid, β-d-fructofuranosyl-6-O-myristoyl-α-d-glucopyranoside (MMS). Surfactant and erythrocytes interaction was studied by measuring hemoglobin release and the changes in water content in the membrane sensed by Laurdan. Using two-photon excitation, three types of measurements were performed: Generalized Polarization (analyzed as average GP values), Fluorescence Lifetime Imaging, FLIM (analyzed using phasor plots) and Spectral imaging (analyzed using spectral phasor). Our data indicate that at sublytical concentration of surfactant (20μM MMS), there is a decrease of about 35% in erythrocytes size, without changes in Laurdan lifetime or emission spectra. We also demonstrate that as hemolysis progress, Laurdan lifetime increased due to the decrease in hemoglobin (strong quencher of Laurdan emission) content inside the erythrocytes. Under these conditions, Laurdan spectral phasor analyses can extract the information on the water content in the membrane in the presence of hemoglobin. Our results indicate an increase in membrane fluidity in presence of MMS.
摘要：
由于脂质组成的多样性和天然膜中蛋白质的存在，表面活性剂和生物膜相互作用的研究特别复杂。更困难的是在体内研究这种相互作用，因为细胞损伤可能会使结果的解释复杂化。因此，该领域的大多数研究都使用人工或模型系统。最用于研究生物膜的模型系统之一是红细胞，因为它们的结构相对简单（它们缺乏只有质膜的细胞核和细胞器）。他们方便的实验操作和可用性。在这种情况下，我们使用兔红细胞作为模型膜，Laurdan（6-月桂酰-2-二甲基氨基萘）作为荧光探针，研究了与肉豆蔻酸蔗糖单酯相互作用促进的膜变化，β-d-呋喃果糖基-6-O-肉豆蔻酰-α-d-吡喃葡萄糖苷(MMS)。通过测量Laurdan感知的血红蛋白释放和膜中水分含量的变化，研究了表面活性剂与红细胞的相互作用。使用双光子激发，进行了三种类型的测量：广义偏振(分析为平均GP值)，荧光寿命成像,FLIM(使用相量图分析)和光谱成像(使用光谱相量分析)。我们的数据表明，在表面活性剂的细分浓度(20μMMMS)下，红细胞大小减少约35%，没有变化的Laurdan寿命或发射光谱。我们还证明，随着溶血的进展，Laurdan寿命由于红细胞内血红蛋白（Laurdan发射的强猝灭剂）含量的减少而增加。在这些条件下,Laurdan光谱相量分析可以提取血红蛋白存在下膜中水分含量的信息。我们的结果表明在MMS存在下膜流动性增加。
