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有望在传感、数据存储、电子和催化等广泛应用中发挥重要作用。人们对制备包括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，这是人工合成的分子所不具备的。然而，众所周知，生物分子对当地环境的变化不稳定，很容易随着温度的变化而降解。如果这样的成分能够与更坚固的成分(如二氧化硅等简单的无机材料)一起被包埋，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使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，并专门位于细胞膜的壁上，在那里它形成有序的晶体阵列，浸泡在脂质双层膜中。这种蛋白质一直延伸到细胞膜上，并且是光敏的，这样特定波长的光就会改变蛋白质的性质，进而允许质子从细胞膜内向外移动。这种显著的效应导致了跨膜的颜色和电荷分离的可逆变化/有效地诱导了一个很小的光致电压/这被用作以被称为ATP的分子的形式存储能量的驱动力。值得注意的是，这种蛋白质可以很容易地以紫色碎片的形式从细菌中提取出来，这些碎片由单层膜和组成BR分子组成，然后用作高灵敏的光致变色和光电材料。我们的计划旨在创造基于这些紫膜(PM)的新纳米材料，这些膜具有增强的机械、化学和热稳定性。为此，我们打算制备包含多层PM的薄膜，然后用非常薄的二氧化硅或聚合物层渗透到各个薄片之间的空间。其目的是制造一系列新型的杂化纳米结构，具有由周期性排列的PM和二氧化硅/聚合物交替层组成的三明治状结构，并从结构和光诱导性能方面对这些材料进行全面表征。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，并证明它们可以在仅有BR失败的条件下工作。

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.