Fig. 2

A The changes of Gel in H₂O₂ (0 mM, 0.5 mM and 1 mM) at different times. B Scanning electron microscopy (SEM) visualization of Gel in 10 mM after 1 h (scale bar = 60 μm). C The photo of MB in Fenton reaction solution incubates with or without the hydrogel (I: MB + Fe, II: MB + Fe + H₂O₂, III: MB + Fe + H₂O₂ + Hydrogel). The place pointed by the black arrow is the hydrogel. D The relative absorbance value of MB triggered by Fenton reaction with or without the hydrogel. (n = 3). *** indicates p < 0.001