Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey , 610 Taylor Road, Piscataway, New Jersey 08854, United States.
J Phys Chem B. 2013 Sep 26;117(38):11249-59. doi: 10.1021/jp402108s. Epub 2013 Jul 16.
Owing to the considerable current interest in replacing fossil fuels with solar radiation as a clean, renewable, and secure energy source, light-driven electron transport in natural photosynthetic systems offers a valuable blueprint for conversion of sunlight to useful energy forms. In particular, intracytoplasmic membrane vesicles (chromatophores) from the purple bacterium Rhodospirillum rubrum provide a fully functional and robust photosynthetic apparatus, ideal for biophysical investigations of energy transduction and incorporation into biohybrid photoelectrochemical devices. These vesicular organelles, which arise by invagination of the cytoplasmic membrane, are the sites of the photochemical reaction centers and the light harvesting 1 (LH1) complex. The LH1 protein is responsible for collecting visible and near-IR radiant energy and funneling these excitations to the reaction center for conversion into a transmembrane charge separation. Here, we have investigated the morphology, fluorescence kinetics and photocurrent generation of chromatophores from Rsp. rubrum deposited directly onto gold surfaces in the absence of chemical surface modifications. Atomic force microscopy showed a significant coverage of the gold electrode surface by Rsp. rubrum chromatophores. By in situ fluorescence induction/relaxation measurements, a high retention of the quantum yield of photochemistry was demonstrated in the photoactive films. Chronoamperometric measurements showed that the assembled bioelectrodes were capable of generating sustained photocurrent under white light illumination at 220 mW/cm(2) with a maximum current of 1.5 μA/cm(2), which slowly declines in about 1 week. This study demonstrates the possibility of photoelectrochemical control of robust chromatophore preparations from Rsp. rubrum that paves the way for future incorporation into functional solar cells.
由于人们对利用太阳能辐射替代化石燃料作为清洁、可再生和安全的能源的浓厚兴趣，自然光合作用系统中的光驱动电子传递为将太阳光转化为有用的能量形式提供了有价值的蓝图。特别是，来自红杆菌的胞内膜泡（类囊体）为光合作用装置提供了一个完全功能强大且稳健的光合作用装置，非常适合于对能量转导进行生物物理研究并将其纳入生物混合光电化学装置中。这些由细胞质膜内陷形成的囊泡细胞器是光化学反应中心和光收集 1（LH1）复合物的所在地。LH1 蛋白负责收集可见光和近红外辐射能，并将这些激发能传递到反应中心，以转化为跨膜电荷分离。在这里，我们研究了直接沉积在金表面上的红杆菌类囊体的形态，荧光动力学和光电流产生，而无需进行化学表面修饰。原子力显微镜显示，红杆菌类囊体大量覆盖了金电极表面。通过原位荧光诱导/弛豫测量，证明了光活性膜中光化学量子产率的高保留率。计时安培测量表明，组装的生物电极能够在 220 mW/cm2 的白光照射下产生持续的光电流，最大电流为 1.5 μA/cm2，在大约 1 周的时间内缓慢下降。这项研究证明了从红杆菌中光电化学控制稳健类囊体制剂的可能性，为将来将其纳入功能型太阳能电池铺平了道路。
