标题： 小极性分子通过磷脂膜的渗透性由巨型磷脂囊泡的渗透膨胀确定 显示英文标题

标题： Permeability of phospholipid membrane for small polar molecules determined from osmotic swelling of giant phospholipid vesicles

摘要： 基于微米大小的巨单层囊泡（GUVs）的渗透肿胀来确定磷脂双分子层渗透性的方法被提出，作为两种现有技术的替代方法：脂质体悬浮液的动态光散射和平面脂质双分子层的电学测量。 在所述技术中，使用微量吸管将单个GUV从蔗糖/葡萄糖溶液转移到含有待研究溶质的等渗溶液中。 在整个实验过程中，使用安装在相位对比显微镜上的数字相机监测并记录囊泡的横截面。 通过最小二乘法进行圆拟合，从记录的囊泡横截面图像中计算出囊泡半径R。 描述了两种从获得的R(t)依赖关系中确定膜渗透性的方法：第一种方法利用球形GUV的R(t)斜率，第二种方法利用囊泡在松弛状态转变为球形状态的转变点附近的R(t)依赖关系。 我们证明这两种方法对膜渗透性的估计是一致的。 显示英文摘要

摘要： A method for determining permeability of phospholipid bilayer based on the osmotic swelling of micrometer-sized giant unilamellar vesicles (GUVs) is presented as an alternative to the two established techniques, dynamic light scattering on liposome suspension, and electrical measurements on planar lipid bilayers. In the described technique, an individual GUV is transferred using a micropipette from a sucrose/glucose solution into an isomolar solution containing the solute under investigation. Throughout the experiment, vesicle cross-section is monitored and recorded using a digital camera mounted on a phase-contrast microscope. Using a least-squares procedure for circle fitting, vesicle radius R is computed from the recorded images of vesicle cross-section. Two methods for determining membrane permeability from the obtained R(t) dependence are described: the first one uses the slope of R(t) for a spherical GUV, and the second one the R(t) dependence around the transition point at which a flaccid vesicle transforms into a spherical one. We demonstrate that both methods give consistent estimates for membrane permeability.