Multifunctional nanotheranostic agents have been highly commended due to the application to image-guided cancer therapy. Herein, based on the chemically disordered face centered cubic (fcc) FePt nanoparticles (NPs) and graphene oxide (GO), we develop a pH-responsive FePt-based multifunctional theranostic agent for potential in vivo and in vitro dual modal MRI/CT imaging and in situ cancer inhibition. The fcc-FePt will release highly active Fe ions due to the low pH in tumor cells, which would catalyze HO decomposition into reactive oxygen species (ROS) within the cells and further induce cancer cell apoptosis. Conjugated with folic acid (FA), the iron platinum-dimercaptosuccinnic acid/PEGylated graphene oxide-folic acid (FePt-DMSA/GO-PEG-FA) composite nanoassemblies (FePt/GO CNs) could effectively target and show significant toxicity to FA receptor-positive tumor cells, but no obvious toxicity to FA receptor-negative normal cells, which was evaluated by WST-1 assay. The FePt-based multifunctional nanoparticles allow real-time monitoring of Fe release by T-weighted MRI, and the selective contrast enhancement in CT could be estimated in vivo after injection. The results showed that FePt-based NPs displayed excellent biocompatibility and favorable MRI/CT imaging ability in vivo and in vitro. Meanwhile, the decomposition of FePt will dramatically decrease the T-weighted MRI signal and increase the ROS signal, which enables real-time and in situ visualized monitoring of Fe release in tumor cells. In addition, the self-sacrificial decomposition of fcc-FePt will be propitious to the self-clearance of the as-prepared FePt-based nanocomposite in vivo. Therefore, the FePt/GO CNs could serve as a potential multifunctional theranostic nanoplatform of MRI/CT imaging guided cancer diagnosis and therapy in the clinic.

As a multifunctional platform for photo-chemo-immunotherapy strategies, FePt/MoS2 nanocomposites shows great potential in cancer theranostic.

Multimodal imaging-guided synergistic anticancer strategies have attracted increasing attention for efficient diagnosis and therapy of cancer. Herein, a multifunctional nanotheranostic agent FePtMn-Ce6/FA (FPMCF NPs) is constructed by covalently anchoring photosensitizer chlorin e6 (Ce6) and targeting molecule folic acid (FA) on ultrasmall homogeneous ternary FePtMn nanocrystals. Response to tumor microenvironment (TME), FPMCF NPs can release Fe 2+ to catalyze H 2 O 2 into •OH by Fenton reaction and simultaneously catalyze hydrogen peroxide (H 2 O 2) into O 2 to overcome the tumor hypoxia barrier. Released O 2 is further catalyzed into 1 O 2 under 660 nm laser irradiation with Ce6. Thus, the FPMCF NPs exhibit superior dual-ROS oxidization capability including ferroptosis chemodynamic oxidization and 1 O 2-based photodynamic oxidization. Interestingly, FPMCF NPs reveal strong photothermal conversion efficiency exposed to an 808 nm laser, which can assist dual-ROS oxidization to suppress solid tumor remarkably. Additionally, Mn 2+ can be released from FPMCF NPs to enhance longitudinal relaxivity (T 1-weighted magnetic resonance (MR) imaging) and Fe-synergistic transverse relaxivity (T 2-weighted MR imaging), which is convenient for diagnosis of solid tumors. Meanwhile, the fluorescent/photothermal (FL/PT) imaging function of FPMCF NPs can also accurately monitor tumor location. Therefore, FPMCF NPs with multimodal MR/FL/PT imaging-guided synergistic chemodynamic/photodynamic/photothermal cancer therapy capability have potential bioapplication in bionanomedicine field.

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Recently, extending single-atom catalysts from mono- to binary sites has been proved to be a promising way to realize more efficient chemical catalytic processes. In this work, atomically dispersed Fe, Pt dinuclear catalysts ((Fe, Pt)SA-N-C) with an ca. 2.38 Å distance for Fe1 (Fe-N3) and Pt1 (Pt-N4) could be precisely controlled via a novel secondary-doping strategy. In response to tumor microenvironments, the Fe-N3/Pt-N4 moieties exhibited synergistic catalytic performance for tumor catalytic therapy. Due to its beneficial microstructure and abundant active sites, the Fe-N3 moiety effectively initiated the intratumoral Fenton-like reaction to release a large amount of toxic hydroxyl radicals (•OH), which further induced tumor cell apoptosis. Meanwhile, the bonded Pt-N4 moiety could also enhance the Fenton-like activity of the Fe-N3 moiety up to 128.8% by modulating the 3d electronic orbitals of isolated Fe-N3 sites. In addition, the existence of amorphous carbon revealed high photothermal conversion efficiency when exposed to an 808 nm laser, which synergistically achieved an effective oncotherapy outcome. Therefore, the as-obtained (Fe, Pt)SA-N-C-FA-PEG has promising potential in the bio-nanomedicine field for inhibiting tumor cell growth in vitro and in vivo.