Ultrasound activation of TiO2 in melanoma tumors

Sonodynamic therapy (SDT) is a new modality using ultrasound (US) to activate certain chemical sensitizers for cancer therapy. In this study, the effect of US combined with a nanoparticle titanium dioxide (TiO2) on melanoma cell was investigated in vitro and in vivo. Melanoma cells (C32) were irradiated with US in the presence and/or absence of TiO2. Cell viability was measured immediately after US irradiation (1 MHz, 0.5 and 1.0 W/cm2 for 10 s). The effect of the combination of TiO2 and US exposure (1 MHz, 1.0 W/cm2, 2 min duration) on subcutaneously implanted C32 solid tumors in mice were investigated by measuring tumor volume regression. The cell viability was significantly decreased only after US irradiation in the presence of TiO2. In vivo results showed significant inhibition of tumor growth in groups treated with TiO2 and US. To our knowledge, this is the first report to demonstrate the cell killing effect of TiO2 nanoparticles under the irradiation US in vitro and in vivo.

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