Oxidation and pH responsive nanoparticles based on ferrocene-modified chitosan oligosaccharide for 5-fluorouracil delivery.

•The nanoparticles of FcCOS have been prepared via the self-assemble method.•The nanoparticles showed sensitive to subtle pH change of surroundings.•NaClO, H2O2 and oxygen played a positive role in promoting disassembly.•The release of 5-FU showed a synergistic effect of pH and oxygen.•We reported a dual-responsive nanoparticle of FcCOS for drug delivery.