RGD-conjugated titanium dioxide nanoparticles: targeted near-infrared photothermal therapy for αvβ3 integrin overexpressed cancer cells

Photothermal agents, which can convert near-infrared light into heat with a minimal attenuation of the energy and prevent undesirable thermal damage to healthy tissue, provided an opportunity for accurate heat delivery to desired sites. Herein, we designed cyclo(Arg-Gly-Asp-D-Tyr-Lys) peptide c(RGDyK)-conjugated TiO2 nanoparticles (TiO2-RGD NPs) with an ideal biocompatibility and targeting property. TiO2-RGD NPs exhibited intense absorbance in near-infrared region, a high stability in physiological conditions, and the photothermal conversion efficiency of similar to 38.5%. Due to the specific affinity between c(RGDyK) and alpha(v)beta(3) integrin, TiO2-RGD NPs showed the high targeting property for U87-MG cells with overexpression of alpha(v)beta(3) integrin. After incubation with TiO2-RGD NPs (100 mu g/mL) and under 808 nm near-infrared laser irradiation (1 W/cm(2)), the viability of MCF-7 cells by deficient expression of alpha(v)beta(3) integrin was similar to 71%, while the viability of U87-MG decreased to similar to 31%, which have been demonstrated as an effective targeting photothermal therapy agent.