PHOTOSYN-STM · Single-Molecule studies of photo-conductance on photosynthetic molecular systems by SPM break-junction measurements

This proposal presents a new fundamental approach to study one of the most outstanding processes in nature at the single-molecule level; the photo-induced charge separation process on molecular photosynthetic systems. The last technical advances, especially on Scanning Probe Microscopies (SPM), have allowed approaching a number of relevant molecular processes to a single-molecule level, fact that has brought a revolutionary view to the field of Molecular Biology and a more quantitative comprehension of fundamental bio-molecular processes. Indeed, examples of single-molecule experiments like folding/unfolding of proteins, DNA-enzymes interactions or molecular conductance measurements have become today a reality. In the last, electrical conductance measurements through a variety of simple molecular architectures have been already performed, and relevant fundamental roles such as the presence of different chemical entities; double bounds and/or chemical electron-acceptors/donors in the conduction mechanism, have been already understood. Being immersed in such an excitingmolecu scenario, we have now the opportunity to go one step further and tackle into the analysis of more complex molecular conductance processes at the single-molecule level. Conductance taking place between specific molecular centers at the primary electron transfer step in Photosynthesis is undoubtedly the most important molecular conductance mechanism in life. We have now all required elements at hand to put such a project in practice; technical instrumentation to measure single-molecule conductance under physiological conditions as well as synthetic routes to design the mimetic molecular connections among the photo-conducting pigment and the corresponding secondary electron-acceptor cofactor to approach the problem. Beyond the valuable scientific contribution, the results of this project will span to the desired implementation of such molecular systems on the current photo-electrical cell technology