Orthogonal near-infrared upconversion co-regulated site-specific O2 delivery and photodynamic therapy for hypoxia tumor by using red blood cell microcarriers

•A novel orthogonal excitations-emissions UCNPs anchored red blood cells (RBC) microcarrier for O2 delivery and PDT.•RBC microcarriers can be generated a large amount of O2 and ROS in hypoxia region under near-infrared irradiation.•RBC microcarriers exhibit abilities to overcome hypoxia and biological barriers with efficient tumor treatment.

Pre-existing hypoxia in tumors can result in an inadequate oxygen supply during photodynamic therapy (PDT), which in turn hampers photodynamic efficacy. To overcome this problem, we developed an orthogonal near-infrared upconversion controlled red blood cell (RBC) microcarriers to selectively deliver O2 in hypoxia area. Moreover, this RBC microcarriers are able to overcome a series of complex biological barriers which include transporting across the inflamed endothelium, evading mononuclear phagocyte system, reducing reticuloendothelial system uptake. Based on these abilities, RBC microcarriers have efficient tumors accumulation and are capable of delivery a large amount of O2 for PDT under near-infrared (NIR) irradiation to realize effective solid tumor eradication.

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