Nano-drug delivery systems with multi-modality imaging capacities are worth pursuing because they integrate diagnostic and therapeutic functions. Herein, we report the design, synthesis and evaluation of modified
iridium sulfide (IrSx) nanoparticles (NPs) for
cancer therapy in vitro and in vivo. This nanosystem was prepared by modifying IrSx with
polyethylene glycol (PEG) conjugated to the targeting
ligand folate (FA) for multimodal imaging-guided combined chemo-
photothermal therapy. Upon PEG modification, the small IrSx NPs (about 4 nm) self-assembled into much larger (about 120 nm) IrSx-PEG-FA NPs, which exhibited high photostability, ideal photothermal effect, high drug loading and pH-/photothermal-responsive drug release properties. By using the model anticancer drug
camptothecin (
CPT), we demonstrated that
CPT@IrSx-PEG-FA can effectively target FA-receptor-positive
cancer cells in vitro and show efficient
tumor accumulation in vivo. The combination of
CPT@IrSx-PEG-FA treatment and irradiation with an 808 nm
laser resulted in complete
tumor elimination. Moreover, photothermal/photoacoustic (PA)/computed tomography (CT) imaging provided an effective means to monitor the
therapeutic effects. Interestingly, the nanoparticles can be cleared, resulting in low systematic toxicity of
CPT@IrSx-PEG-FA. Our work demonstrates that the as-prepared IrSx-PEG-FA NPs present a promising platform for the construction of multifunctional
theranostic agents for
cancer therapy.