Degradable Holey Palladium Nanosheets with Highly Active 1D Nanoholes for Synergetic Phototherapy of Hypoxic Tumors

Pd nanosheets (Pd NSs) have attracted extensive attention due to their promising application in photothermal therapy. However, their photodynamic properties have rarely been reported. Herein, holey Pd NSs (H-Pd NSs) with intrinsic photodynamic and hypoxia-resistant capacities are fabricated for the first time using an anisotropic oxidative etching strategy, which introduces one-dimensional nanoholes with active (100) facets on the hole walls. Gradual degradation of H-Pd NSs is observed in simulated physiological media due to the oxidative etching. In vitro and in vivo studies indicate that the single-component H-Pd NSs can act as a photothermal/photodynamic agent for imaging-guided hypoxic tumor therapy, with a high tumor inhibition rate of 99.7%. This work provides ideas for introducing active facets in metallic pore walls, broadening the application of Pd NSs and the design of biodegradable noble metal nanotheranostic agents for cancer therapy.