Titanium Dioxide Nanoparticles in Advanced Imaging and Nanotherapeutics

Semiconductor photocatalysis using nanoparticulate TiO₂ has proven to be a promising technology for use in catalytic reactions, in the cleanup of water contaminated with hazardous industrial by-products, and in nanocrystalline solar cells as a photoactive material. Metal oxide semiconductor colloids are of considerable interest because of their photocatalytic properties. The coordination sphere of the surface metal atoms is incomplete and thus traps light-induced charges, but also exhibits high affinity for oxygencontaining ligands and gives the opportunity for chemical modification. We use enediol linkers, such as dopamine and its analogs, to bridge the semiconductors to biomolecules such as DNA or proteins. Nanobio hybrids that combine the physical robustness and chemical reactivity of nanoscale metal oxides with the molecular recognition and selectivity of biomolecules were developed. Control of chemical processes within living cells was achieved using TiO₂ nanocomposites in order to develop new tools for advanced nanotherapeutics. Here, we describe general experimental approaches for synthesis and characterization of high crystallinity, water soluble 5 nm TiO₂ particles and their nanobio composites, methods of cellular sample preparation for advanced Synchrotron-based imaging of nanoparticles in single cell X-ray fluorescence, and a detailed experimental setup for application of the high-performance TiO₂-based nanobio photocatalyst for targeted lysis of cancerous or other disordered cells.