Sridharan Arati, Muthuswamy Jit, Pizziconi Vincent B
Harrington Department of Bioengineering, Ira A. Fulton School of Engineering, Arizona State University, Tempe, Arizona 85287, USA.
Langmuir. 2009 Jun 2;25(11):6508-16. doi: 10.1021/la900112p.
In nature, nanoscale supramolecular light harvesting complexes initiate the photosynthetic energy collection process at high quantum efficiencies. In this study, the distinctive antenna structure from Chloroflexus aurantiacusthe chlorosomeis assessed for potential exploitation in novel biohybrid optoelectronic devices. Electrochemical characterization of bacterial fragments containing intact chlorosomes with the photosynthetic apparatus show an increase in the charge storage density near the working electrode upon light stimulation and suggest that chlorosomes contribute approximately one-third of the overall photocurrent. Further, isolated chlorosomes (without additional photosynthetic components, e.g., reaction centers, biochemical mediators) produce a photocurrent (approximately 8-10 nA) under light saturation conditions. Correlative experiments indicate that the main chlorosome pigment, bacteriochlorophyll-c, contributes to the photocurrent via an oxidative mechanism. The results reported herein are the first to demonstrate that isolated chlorosomes (lipid-enclosed sacs of pigments) directly transduce light energy in an electrochemical manner, laying an alternative, biomimetic approach for designing photosensitized interfaces in biofuel cells and biomedical devices, such as bioenhanced retinal prosthetics.
在自然界中，纳米级超分子光捕获复合物以高量子效率启动光合能量收集过程。在本研究中，对来自橙色绿弯菌的独特天线结构——叶绿体进行评估，以探索其在新型生物杂交光电器件中的潜在应用。对含有完整叶绿体及光合装置的细菌片段进行电化学表征，结果表明，光照刺激下工作电极附近的电荷存储密度增加，这表明叶绿体对总光电流的贡献约为三分之一。此外，分离出的叶绿体（无其他光合成分，如反应中心、生化介质）在光饱和条件下可产生光电流（约8 - 10 nA）。相关实验表明，叶绿体的主要色素细菌叶绿素c通过氧化机制对光电流有贡献。本文报道的结果首次证明，分离出的叶绿体（色素的脂质包裹囊）能以电化学方式直接转换光能，为设计生物燃料电池和生物医学装置（如生物增强视网膜假体）中的光敏界面提供了一种仿生替代方法。
