Multifunctional Anticancer Platform for Multimodal Imaging and Visible Light Driven Photodynamic/Photothermal Therapy

As a potential photosensitizer for photodynamic therapy (PDT), pure titanium dioxide has the drawbacks of low tissue penetration and possible damage to skin due to the triggered UV light. To realize near-infrared (NIR) laser-induced multimodal imaging guided therapy, we constructed a multifunctional coreshell structure (TiO2@Y2Ti2O7@YOF:Yb,Tm) by a facile coprecipitation route, followed by an annealing process. Under a single NIR laser irradiation, the highly cytotoxic reactive oxygen species (ROS) required for PDT can be generated due to the energy transfer from YOF:Yb,Tm to the Y2Ti2O7 photocatalyst which is responsive to blue emission (visible light), and the thermal effect can be simultaneously produced due to the nonradiative transition and the recombination of electronhole pairs. The NIR light induced PDT and photothermal therapy (PTT) can efficiently suppress tumor growth, which was evidenced by both in vitro and in vivo results. Moreover, the rare earth ions in the composite make the material have good up-conversion luminescence (UCL) imaging and CT imaging properties, thus achieving the target of synergistic PDT and PTT therapy under the multimodal imaging guidance.