Ag/AgBr Nanocubes Achieve Light-Triggered Doxorubicin Delivery for Enhanced Combined Chemo-Photodynamic Therapy

Abstract Most inorganic drug carriers are difficult to degrade, which limits their use in vivo. Here, PVP-framed Ag/AgBr nanocubes act as both the photosensitizer and the drug reservoir, so that a single light exposure generates reactive oxygen species and releases doxorubicin (DOX) from the same particle. FT-IR of the washed formulation identifies the loaded drug through bands at 1732, 1582 and 1286 cm−1, and the surface potential is unchanged on loading (−22.7 to −22.5 mV in water), placing the drug at or within the PVP layer rather than adsorbed electrostatically. Under irradiation the nanocubes generate ·OH and 1O2, the AgBr converts to Ag; lattice-resolved imaging of the irradiated material reveals Ag(111) at 0.239 nm in one grain and unconverted AgBr in another, while the polymer framework retains its cubic outline, and the DOX fluorescence of the release medium rises over 15 min. In HeLa cells the irradiated formulation reduced viability to 30.3 ± 5.5% of the untreated control at 100 μg mL−1, whereas in the dark viability remained between 86% and 98%. In a HeLa xenograft the irradiated DOX-loaded group was the only one whose mean tumor volume fell below its starting value (−50.2 ± 14.8% on day 12) and it differed from the irradiated carrier alone (Tukey-adjusted p = 0.041). Light therefore gates both arms of the treatment within a single material. Quantitative synergy, a validated DOX-equivalent dose and normal-cell safety remain to be established.