Bimetallic nanostructures show exciting potential as materials for effective photothermal hyperthermia therapy. We report the seed-mediated synthesis of palladium-gold (Pd-Au) nanostructures containing multiple gold nanocrystals on highly branched palladium seeds. The nanostructures were synthesized via the addition of a gold precursor to a palladium seed solution in the presence of oleylamine, which acts as both a reducing and a stabilizing agent. The interaction and the electronic coupling between gold nanocrystals and between palladium and gold broadened and red-shifted the localized surface plasmon resonance absorption maximum of the gold nanocrystals into the near-infrared region, to give enhanced suitability for photothermal hyperthermia therapy. Pd-Au heterostructures irradiated with an 808 nm laser light caused destruction of HeLa cancer cells in vitro, as well as complete destruction of tumor xenographs in mouse models in vivo for effective photothermal hyperthermia.

We present a synthetic protocol for the solution-phase synthesis of monocrystalline, metallic iron nanoparticles based on seed-mediated growth, showing near-single nanometre control over particle size. A shape evolution to cubic nanoparticles is also observed with increasing size. Magnetic properties were measured after surface oxidation, showing the potential of our protocol to tune the magnetism of iron nanoparticles for applications requiring superparamagnetic or ferromagnetic nanoparticles.

The decomposition of organometallic compounds as precursors has revolutionized the synthesis of nanoparticles in solution. However, effective control of size and size distribution of iron nanoparticles has remained challenging due to the high reactivity of iron towards oxygen or oxygen-containing materials. Reported is a decomposition study that shows how metal to ligand bonding and symmetry of the compound can be manipulated to control the size and size distribution of iron nanoparticles in the 6-16 nm range. [Fe(η(5)-C6H3Me4)2] was found to be the optimal precursor with a narrow decomposition temperature range due to its symmetry and the low bond dissociation energy of the ligands from the Fe(ii) center. The precise control of nanoparticle size has enabled the tuning of magnetic properties from superparamagnetic to soft-ferromagnetic desirable for a wide range of biomedical applications.

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