Dual-Stage Light Amplified Photodynamic Therapy against Hypoxic Tumor Based on an O2 Self-Sufficient Nanoplatform.

Tumor hypoxia severely limits the efficacy of traditional photodynamic therapy (PDT). Here, a liposome-based nanoparticle (designated as LipoMB/CaO2 ) with O2 self-sufficient property for dual-stage light-driven PDT is demonstrated to address this problem. Through a short time irradiation, 1 O2 activated by the photosensitizer methylene blue (MB) can induce lipid peroxidation to break the liposome, and enlarge the contact area of CaO2 with H2 O, resulting in accelerated O2 production. Accelerated O2 level further regulates hypoxic tumor microenvironment and in turn improves 1 O2 generation by MB under another long time irradiation. In vitro and in vivo experiments also demonstrate the superior competence of LipoMB/CaO2 to alleviate tumor hypoxia, suppress tumor growth and antitumor metastasis with low side-effect. The O2 self-sufficient LipoMB/CaO2 nanoplatform with dual-stage light manipulation is a successful attempt for PDT against hypoxic tumor.