Surface Modification of TiO2 Nanoparticles to Enhance Biocompatibility and Selectivity for Use in Photodynamic Therapy

TiO2 nanoparticles display excellent UV photoreactivity but are inactive in the visible due to a large band gap. Utilizing hydrothermal treatment of TiO2, uniform (~20 nm diameter) TiO2 nanoparticles were produced. Nanoparticle surfaces were modified with various organosilanes to produce water-stable colloids at biological pH while maintaining photoreactivity. Surface modifiers included a triamine and a thiol. Surface modification provided for both colloidal stability and functionalization of the nanoparticles, which allows for attachment of an antibody for selective biological targeting and eventual use in photodynamic cancer therapies. Improved colloidal stability and photocatalytic activity were observed for modified particles