A
Biodegradable High-Efficiency Magnetic Nanoliposome
Promotes Tumor Microenvironment-Responsive Multimodal Tumor Therapy
Along with Switchable T2 Magnetic Resonance Imaging
We
explored the catalytic activity and magnetic resonance imaging
(MRI) capacity of Cu-doped ultrasmall iron oxides with different doping
ratios. Then, we screened a highly efficient ultrasmall active catalyst
(UAC). Subsequently, a biodegradable magnetic nanoliposome was developed
for multimodal cancer theranostics through pH-sensitive liposome coating
of these UACs. Upon entering the body, the magnetic nanoliposomes
significantly prolonged the metabolic time of UACs and promoted their
accumulation in tumors. Then, the strong photothermal (PT) effect
of the magnetic nanoliposome quickly ablated the tumor, showing promising
PT therapy. Upon entering tumor cells, the magnetic nanoliposome rapidly
degraded into many UACs and released chemotherapeutic drugs, contributing
to chemotherapy. In addition, UACs not only catalyzed Fenton-type
reaction to produce excessive reactive oxygen species (ROS) but also
inhibited the synthesis of endogenous GSH by inactivating glutamyl
cysteine ligase, contributing to cancer ferroptosis. Furthermore,
the assembly-dissociation process of UACs showed the function of magnetic
relaxation switches, significantly enhancing tumor MRI signal change,
achieving a more accurate diagnosis of the tumor. Therefore, this
magnetic nanoliposome splits into many UACs upon drug release and
regulates the tumor microenvironment to overproduce ROS for enhanced
synergistic tumor theranostics, which provides a strategy for developing
next-generation magnetic catalysts with biodegradability and multimodal
antitumor theranostics.