Spin-dependent electron transmission through bacteriorhodopsin embedded in purple membrane.

Spin-dependent photoelectron transmission and spin-dependent electrochemical studies were conducted on purple membrane containing bacteriorhodopsin (bR) deposited on gold, aluminum/aluminum-oxide, and nickel substrates. The result indicates spin selectivity in electron transmission through the membrane. Although the chiral bR occupies only about 10% of the volume of the membrane, the spin polarization found is on the order of 15%.

Spin specific electron conduction through DNA oligomers.

Spin-based properties, applications, and devices are commonly related to magnetic effects and to magnetic materials. Most of the development in spintronics is currently based on inorganic materials. Despite the fact that the magnetoresistance effect has been observed in organic materials, until now spin selectivity of organic based spintronics devices originated from an inorganic ferromagnetic electrode and was not determined by the organic molecules themselves.

How isolated are the electronic states of the core in core/shell nanoparticles?

We investigated how isolated are the electronic states of the core in a core-shell (c/s) nanoparticles (NPs) from the surface, when the particles are self-assembled on Au substrates via a dithiol (DT) organic linker. Applying photoemission spectroscopy the electronic states of CdSe core only and CdSe/ZnS c/s NPs were compared. The results indicate that in the c/s NPs the HOMO interacts strongly with electronic states in the Au substrate and is pinned at the same energies, relative to the Fermi level, as the core only NPs.

Cooperative effect in the electronic properties of human telomere sequence.

The contribution of sequence elements of human telomere DNA to the interaction of DNA with electrons has been analyzed. By applying wavelength dependent low-energy photoelectron transmission and two-photon photoemission spectroscopy, we investigated the density of states of DNA oligomers with partial sequence elements of the human telomere assembled as monolayers on gold. The findings demonstrate the role of the resonance states in the DNA in accepting electrons and the effect of the sequence on these states.

Electronic structure of DNA--unique properties of 8-oxoguanosine.

8-Oxo-7,8-dihydroguanosine (8-oxoG) is among the most common forms of oxidative DNA damage found in human cells. The question of damage recognition by the repair machinery is a long standing one, and it is intriguing to suggest that the mechanism of efficiently locating damage within the entire genome might be related to modulations in the electronic properties of lesions compared to regular bases. Using laser-based methods combined with organizing various oligomers self-assembled monolayers on gold substrates, we show that indeed 8-oxoG has special electronic properties.