Near-Infrared Upconversion Mesoporous Cerium Oxide Hollow Biophotocatalyst for Concurrent pH-/H 2 O 2 -Responsive O 2 -Evolving Synergetic Cancer Therapy.

Tumor hypoxia is typically presented in the central region of solid tumors, which is mainly caused by an inadequate blood flow and oxygen supply. In the conventional treatment of hypoxic human tumors, not only the oxygen-dependent photodynamic therapy (PDT), but also antitumor drug-based chemotherapy, is considerably limited. The use of direct oxygen delivering approach with oxygen-dependent PDT or chemotherapy may potentiate the reactive oxygen species (ROS)-mediated cytotoxicity of the drug toward normal tissues. Herein, a synergetic one-for-all mesoporous cerium oxide upconversion biophotocatalyst is developed to achieve intratumorally endogenous H2 O2 -responsive self-sufficiency of O2 and near-infrared light controlled PDT simultaneously for overcoming hypoxia cancer. Furthermore, the sufficient O2 plays an important role in overcoming the chemotherapeutic drug-resistant cancer caused by hypoxia, therefore inducing tumor cell apoptosis significantly.