Different crystal forms including amorphous, anatase and rutile titania nanoparticles are provided both in nanopowder and dispersion. Our titania nanoparticles have wide size range from 5 nm to 500 nm. Surface functionalized titania particles are also available for covalent conjugation with proteins, antibodies and other biomolecules. Titania nanoparticles find broad applications in skin products, additives, foods, air cleaning due to its strong UV absorption and active photocatalytic properties.