Raman scattering enhancement was observed in systems where different metal oxide semiconductors (TiO<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>, ZrO<sub>2</sub>
and CeO<sub>2</sub>) were modified with enediol ligands. The intensity of Raman scattering was dependent on laser frequency and
correlated with the extinction coefficient of the charge-transfer complex of the enediol ligands and nanoparticles. The
intensity and frequency of the Raman bands was found to depend on the chemical composition of the enediol ligand and
the chemical composition (and crystallinity) of the nanoparticles. The intensity of the Raman signal depends on the
number of surface binding sites, electron density of the ligands and their dipole moment. We also found that Raman
scattering is observed for the bioconjugated system, where a peptide is linked to the surface of the particle through a
catechol linker. These studies are important since these bioconjugates can be used to form the basis of Raman-based, <i>in
vitro</i> and importantly <i>in vivo</i> biodetection, cell labeling and imaging, and nanotherapeutic strategies.
This paper focuses on understanding the THz-phonon mediated transport of polarons in biomolecules, with particular attention on polaron transport in DNA. In order to exploit biology-based approaches to realizing new electronic systems, it is necessary to understand the electrical transport properties and THz-phonon interactions of biomolecules that portend applications both as electrically conductive wires and as structures that facilitate the chemically-directed assembly of massively integrated ensembles of nanoscale semiconducting elements into terascale integrated networks. Special attention is given to charge transport in biomolecules using indirect-bandgap colloidal nanocrystals linked with biomolecules.
We have developed hybrid light responsive TiO<sub>2</sub> nanoparticles electronically linked to PNA oligonucleotides that site specifically bind to double stranded target DNA. This opens a new opportunity for the development of a highly efficient "artificial restriction enzyme" whose activity can be controlled by using light. The work focuses on the use of TiO<sub>2</sub> nanocomposites as analogs of restriction enzymes with unique specificity that does not exist in current biological approaches. TiO<sub>2</sub> nanoparticles electronically linked to DNA or PNA adapters have been site-specifically attached along double stranded λ DNA vectors. Illumination of this assembly results in selective oxidation of DNA at the deepest "thermodynamic traps" located closest to the nanoparticle surface, causing DNA cleavage. We investigate the effect of the sequence and length of DNA and PNA adapters on the specificity of DNA cleavage. Related to this issue, the potential use of TiO<sub>2</sub>/DNA nanocomposites as "rare cutters" that cleave DNA in the places not achieved with existing protein-based enzymes is investigated.