The glucose permeability of bilayers formed from phosphatidylcholine, Brij30, and sodium octadecyl sulfate has been determined via an enzymatic reaction. Glucose is encapsulated in either uni- or multilamellar vesicles (MLV) and its concentration in the dispersion medium is monitored by spectrophotometry analysis through the rate of glucose oxidase-catalyzed reaction of glucose oxidation. A kinetic model of leakage, taking explicitly into account one, two, or nw-walls (nw » 1) for the vesicles and assuming an enzymatic Michaelis-Menten behavior, is proposed and used to fit the experimental data. The two-wall model was chosen to fit experimental data obtained on MLV since an average value of 1.7 bilayers was estimated for MLV by cryo-TEM imaging. A permeability value of 5.8 ± 4.4 10−9 cm/s was found. The proposed model is validated by the measurement of the bilayer permeability deduced from the modeling of glucose leakage from unilamellar vesicles with the same composition. In this latter case, a value of 8.3 ± 0.7 10−9 cm/s is found for the permeability, which is within the error bar of the value found with MLV.
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机译：已通过酶促反应确定了由磷脂酰胆碱，Brij30和十八烷基硫酸钠形成的双层的葡萄糖渗透性。葡萄糖被封装在单层或多层囊泡（MLV）中，并通过分光光度法通过葡萄糖氧化酶催化的葡萄糖氧化反应速率来监测其在分散介质中的浓度。提出了泄漏的动力学模型，该模型明确考虑了囊泡的一个，两个或nw-壁（nw»1），并假定了酶的Michaelis-Menten行为，并用于拟合实验数据。选择两壁模型以适合在MLV上获得的实验数据，因为通过冷冻TEM成像估计MLV的平均值为1.7双层。渗透率值为5.8±4.4 10 −9 cm / s。通过对双层渗透率的测量验证了所提出的模型，该双层渗透率是由具有相同组成的单层囊泡的葡萄糖渗漏建模得出的。在后一种情况下，渗透率的值为8.3±0.7 10 −9 cm / s，该值在MLV值的误差范围内。
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