Electro-optical interaction of carbon nanotubes with photosynthetic assembles

The development of various biohybrid natural or artificial systems for promoting the solar energy conversion is of high priority in contemporary energy research. The fusion of highly dynamic and adaptive photosynthetic structures with easily manipulated inorganic material at nanoscale level might pave the way of new opportunities to improve plant photosynthetic features. It was suggested that part of the energy absorbed by single-walled Carbon NanoTubes (CNTs) may be transferred to photosynthetic reactions and increase photosynthetic activity in vitro and in situ [1]. This experimental clue promoted the possibility to exploit the high light-capturing efficiency and broad absorbance of CNTs to enhance plant light harvesting capacity. The actual mechanism of this phenomenon is still unclear and the limited number of studies dealing with the CNT interplay with PhotoSynthetic Complexes (PSCs) provide controversial indications including both energy/charge transfer forward and from the nanotubes. Here we aimed to gain insights into the electro-optical interactions of CNTs with light-dependent photosynthetic reactions using isolated PSCs and supramolecular assemblies with different level of complexity such as thylakoid membranes, Photosystem II (PSII)-enriched membrane fragments and light-harvesting complexes of PSII. The energy and electron fluxes in the biohybrid (PSCs/CNTs) systems were analysed by steady-state chlorophyll fluorescence and time-resolved fluorescence spectroscopy. The possible processes involved in the energy excitation decay in the photosynthetic structures in the studied model systems will be discussed.