Hoang Khanh C, Malakhov Dmitry, Momsen William E, Brockman Howard L
The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, USA.
Anal Chem. 2006 Mar 1;78(5):1657-64. doi: 10.1021/ac051772m.
Interfacial processes involving peripheral proteins depend on the composition and packing density of the interfacial lipid molecules. As a biological membrane model, lipid monolayers at the gas-liquid interface allow independent control of these parameters. However, measuring protein adsorption to monolayers has been difficult. To aid in this and other studies of the interfacial processes, we have developed an open, microfluidic flow cell with which surface physical properties can be controlled and monitored in well-defined lipid monolayers while varying aqueous-phase composition. Using this apparatus, we implement a recently described fluorescence method (Momsen, W. E.; Mizuno, N. K.; Lowe, M. E.; Brockman, H. L. Anal. Biochem. 2005, 346, 139-49) to characterize the adsorption/desorption of glucagon to 1,2-dioleoyl-sn-glycerol monolayers at 27 mN/m. Analysis of the data gives reasonable and self-consistent results for kinetic and thermodynamic constants. Varying the packing density of 1,2-dioleoyl-sn-glycerol does not alter the extent of glucagon adsorption, but comparable measurements with 1-steaoryl-2-oleoyl-sn-glycero-3-phosphocholine show a critical dependence. Because it allows a high degree of control of both lipid monolayer properties and aqueous-phase composition, this microfluidic flow cell should find wide applicability in many areas of research into interfacial processes.
涉及外周蛋白的界面过程取决于界面脂质分子的组成和堆积密度。作为一种生物膜模型，气液界面处的脂质单分子层能够独立控制这些参数。然而，测量蛋白质在单分子层上的吸附一直很困难。为了辅助进行界面过程的这一研究及其他研究，我们开发了一种开放式微流控流动池，利用它可以在明确界定的脂质单分子层中控制和监测表面物理性质，同时改变水相组成。使用该装置，我们采用了一种最近描述的荧光方法（Momsen, W. E.; Mizuno, N. K.; Lowe, M. E.; Brockman, H. L. Anal. Biochem. 2005, 346, 139 - 49）来表征胰高血糖素在27 mN/m下对1,2 - 二油酰 - sn - 甘油单分子层的吸附/解吸情况。对数据的分析给出了动力学和热力学常数的合理且自洽的结果。改变1,2 - 二油酰 - sn - 甘油的堆积密度不会改变胰高血糖素的吸附程度，但用1 - 硬脂酰 - 2 - 油酰 - sn - 甘油 - 3 - 磷酸胆碱进行的类似测量显示出关键的依赖性。由于它能够高度控制脂质单分子层性质和水相组成，这种微流控流动池在界面过程的许多研究领域应具有广泛的适用性。
