Sub-100nm hollow Au-Ag alloy urchin-shaped nanostructure with ultrahigh density of nanotips for photothermal cancer therapy

The 'sea urchin'-like nanostructures with particular small size (100nm) and abundant multi-tips have not yet been employed for the cancer photothermal therapy (PTT). Here we report sub-100nm hollow Au-Ag alloy nanourchins (HAAA-NUs) with ultrahigh density of nanotips synthesized via a facile seed-mediated growth. The HAAA-NUs exhibit a remarkably integrated high-quality photothermal feature including well-defined but tunable surface plasmon resonance peak, strong absorption (2.2×10¹⁰M^-1cm^-1) as well as high photothermal conversion efficiency (80.4%) in the near-infrared region. Importantly, the HAAA-NUs demonstrate improved photothermal stability verified via continuous exposition and cyclic irradiation of laser beam. The cell assay, invitro cell ablation and invivo breast cancer treatment verify that the HAAA-NUs are superior photothermal agent for photothermal tumor ablation therapy owing to low toxicity and high cell destruction capability.