Multifunctional Bi2WO6 Nanoparticles for CT-Guided Photothermal and Oxygen-free Photodynamic Therapy.

The consumption of oxygen in photodynamic therapy (PDT) significantly exacerbates the degree of hypoxia in tumors, which not only impedes the therapeutic effect of PDT, but also drives local tumor recurrence. To relieve the PDT-induced hypoxia and improve the therapeutic outcome of PDT in cancer treatment, herein we reported a class of Bi2WO6 nanoparticles (NPs) as a robust multifunctional platform, which integrates the abilities for contrast-enhanced computed tomography (CT) imaging, photothermal therapy, and PDT in an oxygen-free manner. The as-obtained Bi2WO6 NPs with a mean diameter of 5.2 nm are stable in phosphate-buffered saline and an in vivo microenvironment-mimicking buffer. The location of the solid tumor could be accurately positioned using Bi2WO6-enhanced CT with higher spatial resolution. After being irradiated with an 808 nm laser, these Bi2WO6 NPs could realize CT-guided local photothermal ablation of the tumor. Meanwhile, •OH radicals were generated simultaneously from the treatment without consuming an oxygen molecule, which enabled these Bi2WO6 NPs to exert photodynamic killing effect in an oxygen-free manner during cancer therapy. Remarkable tumor suppression was observed in mice bearing the HeLa xenograft, supporting the promising application of these multifunctional Bi2WO6 NPs in the combat against cancers through synergistic photothermal and oxygen-free PDT treatment.

Doxorubicin Loaded Chitosan-W18 O49 Hybrid Nanoparticles for Combined Photothermal-Chemotherapy.

Combined treatment is more effective than single treatment against most forms of cancer. In this work, doxorubicin loaded chitosan-W18 O49 nanoparticles combined with the photothermal therapy and chemotherapy are fabricated through the electrostatic interaction between positively charged chitosan and negatively charged W18 O49 nanoparticles. The in vitro and in vivo behaviors of these nanoparticles are examined by dynamic light scattering, transmission electron microscopy, cytotoxicity, near-infrared fluorescence imaging, and tumor growth inhibition experiment. These nanoparticles have a mean size around 110 nm and show a pH sensitive drug release behavior. After irradiation by the 980 nm laser, these nanoparticles show more pronounced cytotoxicity against HeLa cells than that of free doxorubicin or photothermal therapy alone. The in vivo experiments confirm that their antitumor ability is significantly improved, resulting in superior efficiency in impeding tumor growth and extension of the lifetime of mice.