Construction of protein-modified TiO2 nanoparticles for use with ultrasound irradiation in a novel cell injuring method

Recently, our group discovered an alternative titanium dioxide (TiO2) activation method that uses ultrasound irradiation (US/TiO2) instead of ultraviolet irradiation. The pre-S1/S2 protein from hepatitis B virus, which recognizes liver cells, was immobilized to the surface of TiO2 nanoparticles using an amino-coupling method. The ability of the protein-modified TiO2 nanoparticles to recognize liver cells was confirmed by surface plasmon resonance analysis and immuno-staining analyses. After uptake of TiO2 nanoparticles by HepG2 cancer cells, the cells were injured using this US/TiO2 method; significant cell injury was observed at an ultrasound irradiation intensity of 0.4 W/cm2. Together with these results, this strategy could be applied to new cell injuring systems that use ultrasound irradiation in place of photodynamic therapy in the near future.

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