Bio-functional mesolamellar nanocomposites based on intercalated bacteriorhodopsin arrays.

制造具有小尺度结构和多组分的新材料在传感、数据存储、电子和催化等广泛应用中具有重要意义。人们对制备包含生物成分的纳米材料越来越感兴趣，因为蛋白质和酶等分子具有精细调节的活性，而这些活性在合成的分子中是不容易获得的。然而，生物分子对当地环境的变化是出了名的不稳定，并且很容易随着温度的变化而降解。如果这些成分可以与更坚固的成分（如简单的无机材料，如二氧化硅）一起被捕获，那么生物分子就可以稳定下来，由此产生的纳米复合材料可以在更广泛的环境条件下使用。拟议的研究计划旨在利用一种名为细菌视紫红质（BR）的非凡蛋白质来证明这一原理。BR在某些细菌中大量产生，并且特别位于细胞膜壁，在脂质双分子层膜中形成有序的晶体阵列。这种蛋白质一直延伸到细胞膜上，并且具有光敏性，因此某些波长的光会使蛋白质的性质发生变化，从而允许质子从细胞膜内移动到细胞膜外。这种显著的效应导致了膜上颜色的可逆变化和电荷的分离/有效地诱导了一个小的光致电压/作为一种驱动力，以一种叫做ATP的分子的形式储存能量。值得注意的是，这种蛋白质可以很容易地从细菌中提取出来，形成由单片膜和组成BR分子组成的紫色片段，然后用作高灵敏度的光致变色和光电材料。我们的建议是基于这些紫色膜（PM）创造新的纳米材料，这些材料具有增强的机械、化学和热稳定性。为此，我们打算制备由多层pm组成的薄膜，然后用非常薄的二氧化硅或聚合物层渗透到单个薄片之间的空间。其目的是生产一系列新型的混合纳米结构，它们具有三明治状的结构，由周期性排列的PM和二氧化硅/聚合物交替层组成，并在结构和光致特性方面充分表征这些材料。值得注意的是，一个关键目标是证明我们可以基于我们的新型材料制造原型设备，并表明它们可以在BR单独失效的条件下工作。

Making new materials that have small scale structures and multiple components is expected to be of great importance in a wide range of applications such as sensing, data storage, electronics and catalysis. There is a growing interest in preparing nanomaterials that include biological components because molecules such as proteins and enzymes have finely tuned activities not readily available in synthetic counterparts. However, biological molecules are notoriously unstable to changes in the local environment and readily degrade with temperature. If such components can be entrapped along with more robust constituents such as simple inorganic materials like silica, then the biological molecules can be stabilised, and the resulting nanocomposites used under a wider range of environmental conditions. The proposed research programme aims to demonstrate this principle using a remarkable protein called bacteriorhodopsin (BR). BR is produced in large amounts in certain bacteria, and is located specifically in the wall of the cell membrane, where it forms ordered crystalline arrays immersed in the lipid bilayer membrane. The protein extends all the way across the membrane and is photo-sensitive, such that light of certain wavelengths produce a change in the nature of the protein, which in turn allows protons to move from inside to outside the cell membrane. This remarkable effect results in a reversible change of colour and charge separation across the membrane / effectively a small photo-induced voltage is induced / that is used as a driving force for storing energy in the form of a molecule called ATP. Significantly, the protein can be readily extracted from the bacteria in the form of purple fragments comprising single sheets of the membrane and constituent BR molecules, and then used as a highly sensitive photochromic and photoelectric material. Our proposal intends to create new nanomaterials based on these purple membranes (PM) that have enhanced mechanical, chemical and thermal stabilities. For this we intend to prepare films comprising multiple stacks of the PMs, and then infiltrate the spaces between individual flakes with very thin layers of silica or polymers. The aim is to produce a range of new types of hybrid nanostructures that have a sandwich-like architecture consisting of periodically arranged alternating layers of PM and silica/polymer, and to fully characterise these materials in terms of their structure and photo-induced properties. Significantly, a key goal is to demonstrate that we can fabricate prototype devices based on our new types of materials, and show that they can work under conditions where BR alone fails.