Fig. 2

a Time-dependent DLS-measured size changes of FCCF under different pH conditions (pH 7.4, 6.5 and 5.5). b Time-dependent release of Ca²⁺ from the FCCF dispersed in pH 7.4, 6.5 and 5.5 buffers. c Time-dependent dissolved oxygen generation induced by O₂-COF in deoxidized PBS. d Time-dependent dissolved oxygen generation induced by OFCCF in deoxidized PBS (pH 6.5). e UV–Vis absorption of DPBF after 650 nm laser irradiation with H₂O, COF (100 μg mL⁻¹) and OFCCF (100 μg mL⁻¹, pH 6.5). f ESR spectra of FCCF and OFCCF under 650 nm laser irradiation (0.72 W cm⁻², 10 min)