Fig. 1. Schematic illustration of fabrication and boosted radiotherapy of the smart O₂ nanoeconomizer pHPFON-NO/O₂.

a Synthetic procedures. First, sub-50 nm semiconducting polymer brush/fluorocarbon/phenylene triple-hybridized HPFON was prepared by deposition of bissilylated organosilica precursors onto an MSN template via hydrolysis based on the chemical homology principle and selective MSN etching through an ammonia-assisted hot water etching strategy. Then, an in situ polymerization method was applied to conjugate alkyl chains and PEG polymers onto the inner and outer shell of the HPFON for enhanced hydrophobic drug loading as well as improved biocompatibility. Finally, SNAP and O₂ were loaded onto the resultant pHPFON to generate the pHPFON-NO/O₂. b Schematic illustration of the binary “reducing expenditure and broadening sources” tumor oxygenation strategy by programable delivery of NO and O₂ with pHPFON-NO/O₂ to overcome hypoxia-associated therapy resistance for boosted anti-cancer radiotherapy.