Advances of metal-organic framework nanocomposites in photodynamic therapy for hypoxic tumors

As an emerging therapy, photodynamic therapy (PDT) has numerous advantages including low systemic toxicity, precise localization, minimal invasiveness, and good repeatability, demonstrating broad potential for treating various tumors. To improve the hypoxia microenvironment during PDT treatment, researchers often select different nanocarriers to load O2, functional compounds that promote O2 generation, and photosensitizers to construct nanocomposites for enhancing PDT efficacy. Metal-organic framework (MOF) possess high porosity, large specific surface area, and structurally tunable properties, making them excellent nanocarriers for facile synthesis of multifunctional nanocomposites. In recent years, MOF nanocomposites applied in PDT have received widespread attention. This review first introduces the mechanism of PDT, summarizes the influencing factors, and proposes specific improvement strategies for hypoxia tumor. Secondly, synthesis of MOF nanocomposites is introduced according to different metal ions and analyzed to lay a foundation for establishing a synthesis theory of MOF nanocomposites. Thirdly, their applications in PDT for hypoxic tumors are reviewed in detail. Finally, the challenges of MOF nanocomposites in tumor PDT treatment are prospected to provide ideas for their controllable design and efficient cancer treatment applications. [Display omitted]