Facile Synthesis and Intraparticle Self-Catalytic Oxidation of Dextran-Coated Hollow Au–Ag Nanoshell and Its Application for Chemo-Thermotherapy

Galvanic replacement reaction is a useful method to prepare various hollow nanostructures. We developed fast and facile preparation of biocompatible and structurally robust hollow Au–Ag nanostructures by using dextran-coated Ag nanoparticles. Oxidation of the surface dextran alcohols was enabled by catalytic activity of the core Au–Ag nanostructure, introducing carbonyl groups that are useful for further bioconjugation. Subsequent doxorubicin (Dox) conjugation <i>via</i> Schiff base formation was achieved, giving high payload of approximately 35 000 Dox per particle. Near-infrared-mediated photothermal conversion showed high efficacy of the Dox-loaded Au–Ag nanoshell as a combinational chemo-thermotherapy to treat cancer cells.