Imaging-guided photothermal therapy (PTT) by combination of imaging and PTT has been emerging as a promising therapeutic method for precision therapy. However, the development of multicomponent nanoplatforms with stable structures for both PTT and multiple-model imaging remains a great challenge. Herein, we synthesized monodisperse Au-FeC Janus nanoparticles (JNPs) of 12 nm, which are multifunctional entities for cancer theranostics. Due to the broad absorption in the near-infrared range, Au-FeC JNPs showed a significant photothermal effect with a 30.2% calculated photothermal transduction efficiency under 808 nm laser irradiation in vitro. Owing to their excellent optical and magnetic properties, Au-FeC JNPs were demonstrated to be advantageous agents for triple-modal magnetic resonance imaging (MRI)/multispectral photoacoustic tomography (MSOT)/computed tomography (CT) both in vitro and in vivo. We found that Au-FeC JNPs conjugated with the affibody (Au-FeC-Z) have more accumulation and deeper penetration in tumor sites than nontargeting JNPs (Au-FeC-PEG) in vivo. Meanwhile, our results verified that Au-FeC-Z JNPs can selectively target tumor cells with low cytotoxicity and ablate tumor tissues effectively in a mouse model. In summary, monodisperse Au-FeC JNPs, used as a multifunctional nanoplatform, allow the combination of multiple-model imaging techniques and high therapeutic efficacy and have great potential for precision theranostic nanomedicines.

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Stimuli-controlled drug delivery and release is of great significance in cancer therapy, making a stimuli-responsive drug carrier highly demanded. Herein, a multistimuli-controlled drug carrier was developed by coating bovine serum albumin on Fe5C2 nanoparticles (NPs). With a high loading of the anticancer drug doxorubicin, the nanoplatform provides a burst drug release when exposed to near-infrared (NIR) light or acidic conditions. In vitro experiment demonstrated a NIR-regulated cell inhibition that is ascribed from cellular uptake of the carrier and the combination of photothermal therapy and enhanced drug release. The carrier is also magnetic-field-responsive, which enables targeted drug delivery under the guidance of a magnetic field and monitors the theranostic effect by magnetic resonance imaging. In vivo synergistic effect demonstrates that the magnetic-driven accumulation of NPs can induce a complete tumor inhibition without appreciable side effects to the treated mice by NIR irradiation, due to the combined photochemotherapy. Our results highlight the great potential of Fe5C2 NPs as a remote-controlled platform for photochemothermal cancer therapy.

The phase controlled synthesis of iron carbide nanoparticles was proposed through a thermodynamical and dynamical manner by introducing hetero-halide ions.

Nanoparticles (NPs) have recently been well investigated for cancer therapy. Among them, those that are responsive to internal or external stimuli are promising due to their flexibility. In this feature article, we provide an overview on stimuli-sensitive cancer therapy, using pH- and reduction-sensitive NPs, as well as light- and magnetic field-responsive NPs.