Rational Design of Branched Au-Fe 3 O 4 Janus Nanoparticles for Simultaneous Trimodal Imaging and Photothermal Therapy of Cancer Cells.

We report a facile and simple hydrogen reduction method to fabricate PEGylated branched gold (Au)-iron oxide (Fe3 O4 ) Janus nanoparticles (JNPs). Note that the hydrogen induces the formation of Fe3 O4 during the synthesis process. Due to the strong absorption in the near-infrared range, branched Au-Fe3 O4 JNPs showed a significant photothermal effect with a 40 % calculated photothermal transduction efficiency under a laser irradiation of 808 nm in vitro. Owing to their excellent optical and magnetic properties, branched Au-Fe3 O4 JNPs were demonstrated to be advantageous agents for triple-modal magnetic resonance imaging (MRI)/photoacoustic imaging (PAI)/computed tomography (CT) in vitro. Therefore, the synthetic approach could be extended to prepare Au-metallic oxide JNPs for specific applications.