Fig. 3

Preparation of surface-immobilized catalase-immobilized oxygen-releasing microspheres. A The oxygen-releasing microspheres have a core-shell structure, with PVP/H₂O₂ as the core and PLGA as the shell. B Scanning electron microscope image of core-shell microspheres. C Confocal microscopy image of catalase-immobilized oxygen-releasing microspheres. D Changes of hydrogen peroxide content in the culture medium within three weeks after the stem cell transplantation system with different concentrations of catalase-immobilized microspheres were solidified at 37℃ in 1% O₂ and 1% PBS (n = 3). E The living cells of the stem cell transplantation system containing different concentrations of catalase-immobilized microspheres were solidified at 37℃ and cultured in 1% O₂ and 1% PBS for three weeks (n = 3)