Advanced biophotonic materials: developing a toolkit for quantum dot-membrane-protein nanocomposites

光合作用对地球上的生命至关重要，其中的吸收光的蛋白质是生物物理学家灵感的重要来源。相比之下，量子点（QDs）是微小的无机半导体纳米粒子，具有很大的技术价值。在植物生物膜中发现的“光收集”（LH）蛋白，利用协调的色素分子（如叶绿素）网络吸收光的光子。LH蛋白吸收的能量以激发态的形式通过>00 nm的膜转移，具有显著的量子效率（>90%）。然而，LH蛋白仅限于特定的生物色素，并且它们的吸收光谱存在空白，无法捕获太阳光子。量子点可以吸收各种能量的光子，并将能量传递给其他分子。量子点优异的光学特性使它们成为向LH蛋白输送能量（或接受来自LH蛋白的能量）的理想伙伴。项目目标是：(1)设计、生成和表征一个结合量子点和光合蛋白的膜基系统，以增加光合作用的光谱范围。(2)研究了当量子点与该生物杂化系统相结合时，如何影响量子点的能量和电子转移。(3)研究薄膜/量子点材料在纳米技术中的应用（如功能薄膜）。您将系统地比较不同组成的纳米复合材料，例如(i)嵌入脂质双分子层或系在膜表面的量子点，（ii）嵌入聚合物胶束中的量子点，（iii）将上述量子点与一系列光合膜蛋白（LHCII， PSI， PSII）连接，（iv）试验不同化学性质和大小的量子点。您将使用一系列世界级的生物物理工具，包括：光谱学表征光学特性（吸光度，荧光，其他）和各种高端显微镜，以高分辨率（原子力显微镜，荧光显微镜，电子显微镜）可视化颗粒，显示量子点单独对蛋白质的改进。

Photosynthesis is essential for life on Earth and the light-absorbing proteins involved are a great source of inspiration for biophysicists. In contrast, quantum dots (QDs) are tiny inorganic semiconductor nanoparticles of great technologic interest. "Light-harvesting" (LH) proteins, found in plant biomembranes, absorb photons of light using a network of coordinated pigment molecules (e.g. chlorophylls). Energy absorbed by LH proteins is transferred as excited electronic states through membranes >100 nm with remarkable quantum efficiency (>90%). Yet, LH proteins are limited to specific biological pigments and their absorbance spectrum has gaps where solar photons are not harvested. QDs can absorb photons of a wide range of energies and transfer the energy to other molecules. The excellent optical properties of QDs make them an ideal partner for channelling energy to (or accepting energy from) LH proteins.Project objectives are to: (1) Design, generate and characterize a membrane-based system that combines QDs with photosynthetic proteins in order to increase the spectral range of photosynthesis. (2) Study how energy, and electron, transfer from QD is affected when they are interfaced with this biohybrid system. (3) Investigate use of your membrane/QD materials for applications to nanotechnology (e.g. functional thin-films). You will systematically compare nanocomposites of different compositions, e.g. (i) QDs embedded into the lipid bilayer or tethered to the membrane surface, (ii) QDs embedded within polymer micelles (iii) interfacing the above with a series of photosynthetic membrane proteins (LHCII, PSI, PSII), (iv) trialling QDs of different chemistries and sizes. You will use a range of world-class biophysical tools including: spectroscopy to characterize optical properties (absorbance, fluorescence, other) and various high-end microscopies to visualize the particles at high resolution (atomic force microscopy, fluorescence microscopy, electron microscopy), showing the improvement that QDs make over the protein alone.