Bio-nano physics
- interaction of photosynthetic proteins with nanostructures
The effect of the interaction of nanostructures on the optical properties of pigment proteins is investigated in our lab. An interesting class of pigment proteins is comprised by the photosynthetic light-harvesting (LH) systems. LH systems handle the harvesting of solar energy and the transfer of the captured energy to other proteins.
It was recently shown by a number of groups that the efficiency of LH systems is enhanced by plasmonic nanoparticles placed close to them. In our group we found that the enhancement is accompanied by a modification of the function of the LH systems. Such modifications of the protein function represent a clear intervention in their natural behavior.
The observation of a strong enhancement of Photosystem I by plasmonic nanostructures was the initial point where we decided to investigate these processes in more detail. An enhanced absorption/emission close to nanostructures gives strong indications that a more efficient function of the - almost perfect - LH systems is possible in hybrids formed by LH systems and nanostructures.
One of our major goals is the construction of a hybride system with enhanced LH efficiency usable for biological solar cells or for H2 production. In cooperation with the AK Meixner and AK Kern at the University of Tübingen, special nanostructured surfaces are produced and characterized. And the influence of their plasmonic properties on the optical response of LH is investigated at the single-molecule level in our lab.
One reason for doing experiments at the single-molecule level is the possibility to switch off the ensemble averaging completely. Then, e.g. the relative orientation between the LH systems and the nanostructures can be determined. This knowledge is essential to get new insights into the amplification/modification processes. We think that these investigations are fundamental for the development of efficient biological solar cells or biochips.