Event Information
DNA Photonics - Probing Light-Induced Dynamics in DNA on the Femtosecond Time Scale
- Abstract:
The first generation of experiments on photoinduced electron transfer (ET) in DNA has spawned a basic mechanistic picture from which simple kinetic models were derived. In these models ET through the base stack has been reduced to a static donor-bridge-acceptor problem. Recent experimental and theoretical results have demonstrated that structural dynamics are critical for a comprehensive mechanistic understanding of the ET process. While the initial controversies regarding the long-range conductivity properties and wire-type behavior of DNA have been settled, a new field, DNA Photonics, has emerged around the photophysics of nucleic acids. The contributions that can be expected from future studies in DNA Photonics will likely answer the question whether - and to what extent - DNA can be used as a functional building block in molecular nanoscale devices. They will also be focused on the complex interactions between structural and electronic properties of DNA which are profound for biomedical applications such as DNA-targeted drug design. In this paper we report about our recent experimental efforts which are part of the second generation of studies to expand the new and highly exciting field of DNA Photonics. Experimental data from several different classes of functionalized DNA systems will be presented to illuminate the relationship between structural dynamics and charge injection/migration using state-of-the art femtosecond broadband spectroscopy. Our results present strong evidence for the involvement of hydrogen bond dynamics which must be considered as a specific mode of solvation dynamics inside the DNA helix. Finally, we emphasize the importance of the initial electronic excitation. Thus, ultrafast electronic energy migration, dissipation and (de)localization must be included into the theoretical description of light-induced dynamics in DNA.
Photonics Seminar