Fig. 2

(A) Colorimetric detection of •OH generated by mPDA@CuO₂ NRs at different pH values based on the TMB assay. UV-vis spectra and photographs (inset) of TMB aqueous solution incubated with different concentrations of H₂O₂ in the presence of mPDA@CuO₂ NRs (100 µg/mL) pretreated in an acidic solution for (B) 1 h, (C) 24 h, and (D) 48 h. (E) TEM images of mPDA@CuO₂ NRs (top), mPDA@CuO₂ NRs treated in an acidic solution for 1 h (middle), and mPDA@CuO₂ NRs treated in an acidic solution for 24 h (bottom). Scale bar = 500 nm