Metal–organic frameworks (MOF) have attracted
great potential
in sonodynamic therapy (SDT) owing to large sonosensitizers’
loading and fast reactive oxygen species’ (ROS) diffusion;
however, the low ligand-to-metal charge transfer efficiency sharply
impairs the SDT effect. Herein, we report the design of MIL@Ag heterostructures
with high electron–hole pairs separation efficiency and enhanced
diverse ROS generation ability for deep-seated cancer treatment and
bacterial infection. The MIL@Ag heterostructure is composed of Ti-based
MOFs (named MIL), on which are in situ assembled silver nanoparticles
(Ag NPs). The electrochemical experiments and density functional theory
calculations verify that the introduction of Ag NPs can significantly
improve the electron transfer efficiency and O2 adsorption
capacity of MIL. Under ultrasound irradiation, the doped Ag NPs can
trap the activated electrons from MIL to reduce surrounding O2 and produce superoxide radicals (•O2
–), while the activated holes enable oxidizing H2O to produce hydroxyl radicals (•OH). Thus, they efficiently
improve the therapeutic efficiency of SDT. MIL@Ag-PEG-mediated SDT
implements A549 cancer cells’ killing under a tissue barrier
of 2 cm and eradicates the bacterial infection of Staphylococcus
aureus, thus promoting wound healing. Therefore, MIL@Ag-PEG
provides a promising strategy for augmenting SDT performance by rational
heterostructure design of sonosensitizers.