Enhanced Photocurrent Generation by Photosynthetic Bacterial Reaction Centers through Molecular Relays, Light-Harvesting Complexes, and Direct Protein-Gold Interactions
Enhanced Photocurrent Generation by Photosynthetic Bacterial Reaction Centers through Molecular Relays, Light-Harvesting Complexes, and Direct Protein-Gold Interactions
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DOI：
10.1021/la2013528
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发表时间：
2011-08-16
期刊：
影响因子：
3.9
通讯作者：
Frese, Raoul N.
中科院分区：
文献类型：
--
作者：
den Hollander, Mart-Jan;Magis, J. Gerhard;Frese, Raoul N.
利用蛋白质作为太阳能电池、生物电子学和传感器的纳米器件通常需要将电子转移到导电材料或从导电材料转移电子。在这里，我们报告的努力，以最大限度地提高光电流产生的细菌光合反应中心色素蛋白质复合物（RC）与金属电极的接口。研究了将RC粘附到裸金电极上的可能性，以最小化蛋白质嵌入的电子转移辅助因子与金属表面之间的电子隧穿距离。尽管在电极或工程化连接体上不存在涂层以实现RC在表面上的定向沉积，但仍实现了显著的光电流。与SAM覆盖的金电极的比较表明，由于在光敏颜料和金属之间没有绝缘层，实现了增强的光电流密度。利用被捕光1复合物包围的RC导致更高的光电流，令人惊讶的是，这不是由于增强的光吸收，而是可能由于均匀取向的RC-LH 1复合物的更好的表面覆盖以及可以充当连接线的四血红素细胞色素的存在。细胞色素c（cyt-c）作为分子中继的引入也产生了电流的增加，可能是通过插入粘附的RC或RC-LH 1复合物和电极之间来介导电子转移。不同的顺序，其中组件被引入到电极表明，动态重排的RC和细胞色素C发生在裸露的金属表面。在可用的照明功率范围内不能检测到电流产生的上限，RC-LH 1复合物达到的最大电流密度为25 μ A/cm（2）的量级。在环境条件下，可以连续产生几个小时或几天的高电流。
The utilization of proteins as nanodevices for solar cells, bioelectronics, and sensors generally necessitates the transfer of electrons to or from a conducting material. Here we report on efforts to maximize photocurrent generation by bacterial photosynthetic reaction center pigment-protein complexes (RCs) interfaced with a metal electrode. The possibility of adhering RCs to a bare gold electrode was investigated with a view to minimizing the distance for electron tunneling between the protein-embedded electron-transfer cofactors and the metal surface. Substantial photocurrents were achieved despite the absence of coating layers on the electrode or engineered linkers to achieve the oriented deposition of RCs on the surface. Comparison with SAM-covered gold electrodes indicating enhanced photocurrent densities was achieved because of the absence of an insulating layer between the photoactive pigments and the metal. Utilizing RCs surrounded by light-harvesting 1 complex resulted in higher photocurrents, surprisingly not due to enhanced photoabsorption but likely due to better surface coverage of uniformly oriented RC-LH1 complexes and the presence of a tetraheme cytochrome that could act as a connecting wire. The introduction of cytochrome-c (cyt-c) as a molecular relay also produced increases in current, probably by intercalating between the adhered RCs or RC-LH1 complexes and the electrode to mediate electron transfer. Varying the order in which components were introduced to the electrode indicated that dynamic rearrangements of RCs and cyt-c occurred at the bare metal surface. An upper limit for current generation could not be detected within the range of the illumination power available, with the maximum current density achieved by RC-LH1 complexes being on the order of 25 mu A/cm(2). High currents could be generated consecutively for several hours or days under ambient conditions.