Gold-doped TiO₂ (Au/TiO₂) nanocomposites were utilized to improve the photocatalytic inactivation effect on human colon carcinoma LoVo cells. The Au/TiO₂ samples doped with different amounts of Au (1 wt%, 2 wt%, 4 wt%) were prepared by a chemical reduction method and used to photokill the LoVo cells. It was found that the photocatalytic inactivation effect of the TiO₂ nanoparticles on LoVo cancer cells could be greatly improved by the surface modification of Au nanoparticles. Furthermore, the loading amount of Au on the surface of the TiO₂ nanoparticles affected the photocatalytic inactivation efficiency strongly, and it was observed that the most efficient sample was 2 wt% Au/TiO₂. Under the irradiation of UV light (λ_max＝365 nm, intensity＝1.8 mW/cm²) for 110 min, all of the LoVo cancer cells were killed by 50 μg/mL 2 wt% Au/TiO₂. But for 50 μg/mL TiO₂ nanoparticles, only 70% cancer cells could be killed under the same condition.

Key words: TiO₂, Au/TiO₂ nanocomposite, human colon carcinoma LoVo cell, photocatalytic killing effect