Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University , 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
Faculty of Chemistry, Materials and Bioengineering, Kansai University , 3-3-35 Yamatecho, Suita 564-8680, Japan.
Langmuir. 2017 Jun 13;33(23):5752-5759. doi: 10.1021/acs.langmuir.7b00463. Epub 2017 May 31.
Substrate-supported planar lipid bilayers (SPBs) are being utilized as a versatile model system of the biological membrane. However, the proximity between the solid support and membrane limits utility of SPBs for the functional analyses of membrane proteins. Here, we present a model membrane that can enlarge the distance between the substrate surface and the membrane by combining a stable scaffold of polymerized lipid bilayer with a hydrophilic polymer brush. A micropatterned SPB was generated by the lithographic polymerization of diacetylene lipids and subsequent incorporation of natural (fluid) lipid bilayers. Hydrophilic polymer brush of poly-2-methacryloyloxyethyl phosphorylcholine (poly(MPC)) was formed on the surface of polymeric bilayer by the in situ atom transfer radical polymerization (ATRP) in aqueous solution, in the presence of embedded fluid lipid bilayers. A model membrane protein (Haloquadratum walsbyi bacteriorhodopsin: HwBR) could be reconstituted into the polymer brush-supported bilayers with significantly reduced immobile molecules. Furthermore, the polymer brush terminals could be functionalized by successively polymerizing MPC and 2-aminoethyl methacrylate (AMA). The reactive amine moiety of poly(AMA) enables to conjugate a wide range of biological molecules and surfaces to the membrane. The combination of micropatterned bilayer and polymer brush mimics the two- and three-dimensional structures of the biological membrane, providing a platform to assay membrane proteins in a truly biomimetic environment.
支撑基底的平面脂双层（SPB）被用作生物膜的多功能模型系统。然而，由于固体基底与膜之间的接近程度限制了 SPB 在膜蛋白功能分析中的应用。在这里，我们提出了一种模型膜，它可以通过将聚合脂质双层的稳定支架与亲水聚合物刷结合来扩大基底表面与膜之间的距离。通过二乙炔脂质的光刻聚合以及随后在嵌入的天然（流体）脂质双层中加入天然脂质双层，可以生成微图案化的 SPB。亲水聚合物刷聚（2-甲基丙烯酰氧基乙基磷酸胆碱）（poly(MPC)）通过在水溶液中存在嵌入的流体脂质双层的情况下进行原位原子转移自由基聚合（ATRP）而形成在聚合双层的表面上。模型膜蛋白（Haloquadratum walsbyi 菌视紫红质：HwBR）可以再构成聚合物刷支撑的双层中，其中不可移动的分子显著减少。此外，聚合物刷末端可以通过依次聚合 MPC 和 2-氨基乙基甲基丙烯酸酯（AMA）进行官能化。聚（AMA）的反应性胺部分能够将广泛的生物分子和表面共轭到膜上。具有微图案化双层和聚合物刷的组合模拟了生物膜的二维和三维结构，为在真正仿生环境中测定膜蛋白提供了一个平台。
