PRIN 2012NRRP5 (DTA.AD005.066)
Thematic area
Earth system science and environmental technologies
Project area
Tecnologie e processi per l'ambiente (DTA.AD005)Structure responsible for the research project
Research Institute on Terrestrial Ecosystems (IRET)
Project manager
CHIARA BALDACCHINI
Phone number: 0763/374903
Email: chiara.baldacchini@ibaf.cnr.it
Abstract
Blue Copper Proteins (BCPs) are Electron Transfer (ET) proteins that act as mobile electron carriers in a wide variety of biological functions. ET is a single electron process, occurring with low dissipation, over relatively long distances, and in a very fast, efficient and directional way. In BCPs, ET involves the Cu ion placed in the active site, able to switch between two oxidation states. Its peculiar coordination geometry, and the resulting electronic structure, endow BCPs with an intense optical absorption band, whose excitation induces a ligand-to-metal charge transfer transition related to the phonons of the active site, mimicking the physiological ET. This results in an intriguing coupling among optical transitions, electronic conduction and vibronic properties that, together with the nanoscale dimensions and the biorecognition and biocatalysis abilities, render BCPs optimal candidates for integration in hybrid bio-optoelectronic and biosensor devices. In this perspective, the full understanding of the mechanisms underlying such a coupling and of its effect on the biological ET efficiency are fundamental prerequisites to control and fully exploit BCP potentialities.
Goals
In the present project, an innovative experimental approach will allow to deeply and simultaneously explore the properties of single BCPs adsorbed on metallic and semiconducting surfaces: the vibrational spectra and the transport characteristics of single BCPs under optical excitation will be measured at the same time by means of an advanced apparatus that will be obtained by coupling a Raman spectrometer and a nanoscope for Scanning Tunnelling Microscopy (STM) and Conductive Atomic Force Microscopy (CAFM). In particular, the vibronic structure of optically active molecules will be obtained by enhancing the Resonant Raman (RR) signal cross-section by positioning the microscope metallic tip on top of single BCPs (Tip-Enhanced Raman Spectroscopy: TERS). At the same time, the excited state tunnelling parameters, which are important to understand and to control the tunnelling mechanism at the basis of the ET, will be achieved by STM. Instead, by means of CAFM, the conductivity across the optically activated protein milieu will be measured, obtaining crucial information on the intramolecular conduction mechanisms.
Start date of activity
23/10/2013
Keywords
Bio-optoelectronics, Electron transfer, scanning probe microscopies
Last update: 05/01/2025