The time-dependent increment of the absorbance signal was measured up to 7 minutes (~ 400 seconds) with three groups (OA+ H2O2, OA+ H2O, Buffer+ H2O2) equivalent as previous groups for colorimetric assay, providing nanozyme can consume the substrate (e.g., H2O2) consistently until saturation (Figure ) . The substrate-concentration-dependent absorbance signal linearity was measured before the kinetic analysis, providing its standard curve (R 2 close to 0.99 approximately, and substrate concentration/linear range: 0 -50 µM) (Figure ).