TiO2-DNA Nanocomposites for Imaging and Therapeutic Applications

G.E. Woloschak
Northwestern University, US

Keywords: TiO2 oligonucleotide, nanocomposites

Summary:

TiO2 oligonucleotide nanocomposites used in our studies are 45 Å nanoparticles of titanium dioxide semiconductor combined with oligonucleotide DNA(s) or peptides. The titanium nanoparticle in the nanocomposites is photoreactive and the oligonucleotide has base-pairing specificity. Exposure to electromagnetic radiation of energies greater than 3.2 eV results in charge separation, leading to irreversible trapping of protons and cleavage of DNA associated with the nanocomposite. In addition to DNA, we have been able to attach to the surface fluorescent materials and MR contrast agents thus permitting multifunctional use of the nanoparticles. Peptides (specific for Human Papilloma Virus or EGF) and DNA/PNAs attached to the surface have been used for intracellular and extracellular targeting of nanoparticles in cells in culture. In these studies, an FeOx core provides for MR contrast and fluorescent probes attached to the surface (Cy5) have permitted localization of the nanoconstructs within cells. X-ray fluorescence microscopy has allowed us to directly detect nanoparticles in cells and tissues of animals injected intra-arterially with nanocomposites.