Long-Term Oxygen Storage Nanosystem for Near-Infrared Light-Triggered Oxygen Supplies to Antagonize Hypoxia-Induced Therapeutic Resistance in Nasopharyngeal Carcinoma

O-2-delivering nanosystems have been used to antagonize hypoxia-induced tumor therapeutic resistance. However, short-time oxygen storage is still a bottleneck for these O-2-delivering nanosystems, which results in a decrease in blood circulation time and accumulation of oxygen in tumors, thus reducing the tumor therapeutic efficacy. Herein, a long-term oxygen storage nanosystem (O-2-PIr@Si@PDA) is designed to overcome hypoxia for the treatment of nasopharyngeal carcinoma. This nanosystem is constructed by using perfluorooctyl bromide (PFOB) core as the oxygen carrier, functionalized with an oxygen sensitive probe (Ir(III) complex) and subsequently enclosed with an ultrathin-walled silica shell. Due to the silica shell, this nanosystem can store oxygen for longer than 7 days. The oxygen in the O-2-PIr@Si@PDA nanosystem can be released quickly with the temperature-responsive rupture of the silicon shell under near-infrared (NIR) irradiation. The oxygen storage and release can be self-monitored using the Ir(III) complex with its luminescence effect. As expected, this multifunctional nanosystem in combination with NIR irradiation not only inhibits tumor growth by alleviating hypoxia, but also enhances the effect of oxygen-sensitized radiotherapy against nasopharyngeal carcinoma. Taken together, this study offers a novel strategy for designing long-term oxygen storing nanosystem to relieve tumor hypoxia, thus improving the precise cancer therapeutic efficacy.