To retain the agents in
tumors for
cancer diagnosis and
therapy, and then to remove them from the body, are key for the clinical applications of ideal inorganic
theranostic agents. To meet these needs, we have developed a transformed
theranostic platform, employing PVP coated
Fe3S4 tetragonal nanosheets (TNSs), which could effectively accumulate in the
tumor under magnetic targeting, whilst gradually transforming to small particles (∼5 nm) over three weeks. These were then effectively excreted from the body in normal physiological conditions after exerting their
therapeutic effect. The aqueous dispersion of PVP coated
Fe3S4 TNSs had an intense near-infrared absorption, excellent photothermal conversion efficiency (64.3%) and great T2 weighted magnetic resonance imaging properties (71.3 mM-1 S-1). In addition,
Fe3S4 TNSs could realize a synergistic
photothermal therapy (PTT)/chemodynamic
therapy (CDT), because the localized heat produced by PTT from the defect-rich structure could enhance the Fenton process by utilizing the overproduced H2O2 in the tumor microenvironment, and in return, the produced ˙OH could inhibit
tumor growth and recurrence after PPT. We thus developed a high-efficiency inorganic
theranostic platform which was effectively cleared from the body. This will open up a new avenue for the design of inorganic agents for clinical applications in the future.