Figure 4: Production of reactive free radicals under different irradiation by fluorescence spectrum. Note: (A) Reactive oxygen species generation of various samples with DCFH as the probe. (B) NO generation of various samples with 4,5-diaminofluorescein as the probe. (C) The change of NO level at different concentrations of vitamin C in L-Arg@PCN@Mem. (D) NO release of L-Arg@PCN@Mem under ON-OFF irradiation. hv: Light irradiation; Ft/F0: relative fluorescence intensity. DCFH: 2′,7′-dichlorofluorescin; L-Arg: L-arginine; PCN: porous coordination network; Mem: cancer cell membrane; NO: nitric oxide. Reprinted with permission from Wan et al.