Physical Damage on Giant Vesicles Membrane as a Result of Methylene Blue Photoirradiation
Physical Damage on Giant Vesicles Membrane as a Result of Methylene Blue Photoirradiation
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DOI：
10.1016/j.bpj.2013.11.4457
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发表时间：
2014-01-07
影响因子：
3.4
通讯作者：
Itri, Rosangela
中科院分区：
文献类型：
--
作者：
Mertins, Omar;Bacellar, Isabel O. L.;Itri, Rosangela
在这项研究中，我们追求一个更密切的分析，促进对巨大的单层囊泡膜的二油酰-sn-甘油-3-磷酸胆碱（DOPC）或1-棕榈酰-2-油酰-sn-甘油-3-磷酸胆碱（POPC），通过照射亚甲蓝存在于巨大的单层囊泡溶液中的光损伤。通过光学显微镜和电变形实验，对囊泡膜的物理损伤进行了跟踪，并在膜表面积和渗透性的变化方面的磷脂氧化进行了评价。正如预期的那样，氧化修饰了磷脂的结构特征，导致显著的膜改变。通过比较DOPC与POPC制成的膜，我们观察到，作为亚甲基蓝浓度的函数的孔形成和囊泡降解的速率在DOPC的情况下遵循扩散定律，在POPC的情况下遵循线性变化。我们将这种情况归因于氧化物种的成核过程中的扩散限制的生长制度DOPC和POPC的情况下，一个均匀的成核过程。在此基础上，建立了与实验数据吻合较好的反应扩散方程模型。这一信息表明，光敏化反应的结果严重依赖于膜中存在的脂质的类型。
In this study we pursue a closer analysis of the photodamage promoted on giant unilamellar vesicles membranes made of dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), by irradiating methylene blue present in the giant unilamellar vesicles solution. By means of optical microscopy and electro-deformation experiments, the physical damage on the vesicle membrane was followed and the phospholipids oxidation was evaluated in terms of changes in the membrane surface area and permeability. As expected, oxidation modifies structural characteristics of the phospholipids that lead to remarkable membrane alterations. By comparing DOPC- with POPC-made membranes, we observed that the rate of pore formation and vesicle degradation as a function of methylene blue concentration follows a diffusion law in the case of DOPC and a linear variation in the case of POPC. We attributed this scenario to the nucleation process of oxidized species following a diffusion-limited growth regime for DOPC and in the case of POPC a homogeneous nucleation process. On the basis of these premises, we constructed models based on reaction-diffusion equations that fit well with the experimental data. This information shows that the outcome of the photosensitization reactions is critically dependent on the type of lipid present in the membrane.