Fig. 2. CL-driven photoisomerization for in vitro CPT-controlled release from CLDRSs. (a) Illustration of CL-triggered drug release mechanism of CLDRSs. (b) Changes in TEM and DLS of PEAZO-PCD NPs, CPT@PEAZO-PCD NPs, CPPO@PEAZO-PCD NPs, and CLDRSs after CL of CPT irradiation (CL induced by 2 mM H₂O₂). Scale bar, 100 nm. (c) Drug release curves of CPT@PEAZO-PCD NPs under H₂O₂ (1 mM) treatment. (d) Drug release curves of CLDRSs under different intensity of CL of CPT irradiation. (e) Drug release curves of CLDRSs under CL of CPT irradiation. Secondary CL irradiation indicates addition of 0.05 mM H₂O₂ or 0.5 mM H₂O₂ to enhance CL at the 16th hour. Error bars indicate the s.d. (n = 3).