Riedel René, Frese Natalie, Yang Fang, Wortmann Martin, Dalpke Raphael, Rhinow Daniel, Hampp Norbert, Gölzhäuser Armin
Faculty of Chemistry and Materials Sciences Center, University of Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Universitätsstraße 25, D-33615 Bielefeld, Germany.
Beilstein J Nanotechnol. 2021 Jan 22;12:93-101. doi: 10.3762/bjnano.12.8. eCollection 2021.
A freestanding ultrathin hybrid membrane was synthesized comprising two functional layers, that is, first, a carbon nanomembrane (CNM) produced by electron irradiation-induced cross-linking of a self-assembled monolayer (SAM) of 4'-nitro-1,1'-biphenyl-4-thiol (NBPT) and second, purple membrane (PM) containing genetically modified bacteriorhodopsin (BR) carrying a C-terminal His-tag. The NBPT-CNM was further modified to carry nitrilotriacetic acid (NTA) terminal groups for the interaction with the His-tagged PMs forming a quasi-monolayer of His-tagged PM on top of the CNM-NTA. The formation of the Ni-NTA/His-tag complex leads to the unidirectional orientation of PM on the CNM substrate. Electrophoretic sedimentation was employed to optimize the surface coverage and to close gaps between the PM patches. This procedure for the immobilization of oriented dense PM facilitates the spontaneous fusion of individual PM patches, forming larger membrane areas. This is, to our knowledge, the very first procedure described to induce the oriented fusion of PM on a solid support. The resulting hybrid membrane has a potential application as a light-driven two-dimensional proton-pumping membrane, for instance, for light-driven seawater desalination as envisioned soon after the discovery of PM.
合成了一种独立的超薄混合膜，它由两个功能层组成，即首先是通过电子辐照诱导4'-硝基-1,1'-联苯-4-硫醇（NBPT）的自组装单分子层（SAM）交联产生的碳纳米膜（CNM），其次是含有携带C末端组氨酸标签的基因修饰细菌视紫红质（BR）的紫膜（PM）。对NBPT-CNM进行进一步修饰，使其带有次氮基三乙酸（NTA）末端基团，以便与带有组氨酸标签的PM相互作用，在CNM-NTA顶部形成带有组氨酸标签的PM的准单分子层。Ni-NTA/组氨酸标签复合物的形成导致PM在CNM底物上单向取向。采用电泳沉积法优化表面覆盖率并封闭PM斑块之间的间隙。这种固定取向致密PM的方法有助于单个PM斑块的自发融合，形成更大的膜面积。据我们所知，这是首次描述的在固体支持物上诱导PM取向融合的方法。所得的混合膜具有作为光驱动二维质子泵膜的潜在应用，例如，用于光驱动海水淡化，这在发现PM后不久就被设想出来了。
