Figure 1.

Schematic illustration of the two-stage oxygen delivery system. After intravenous injection, PFTBA@HSA nanoparticles accumulate at the tumor site due to the EPR effect and release physically bound O₂ (1^st stage oxygen supply). At the same time, PFTBA could effectively inhibit platelet activation in the tumor blood vessels to disrupt well-maintained tumor vessel barriers, which then leads to increased RBCs (red blood cell) infiltration and oxygen delivery by RBCs in the tumor (2^nd stage oxygen supply).