Hyperthermic Core-Shell Silver-Gold Nanoparticles: Green Synthesis and Adsorption-Uptake by Macrophages, Fibroblasts and Cancer Cells.

Gold-coated silver nanoparticles (Ag@AuNPs) are synthesized by green synthesis using Vaccinium corymbosum as reducing agent. The obtained Ag@AuNPs present a core-shell structure with nanostar shape. The absorption spectrum of these nanoparticles shows a prominent band centred at 680 nm, within the optimal range for photothermal applications. Dispersions of Ag@AuNPs in water, 1.87 10 NPs/mL, reach a temperature of 44.3 °C under laser excitation in 10 minutes, which is suitable for hyperthermia therapy. The internalization of Ag@AuNPs, at a concentration of 3 10 NPs/ml, by macrophages (Raw 264.7), human fibroblasts (Hs27), and cancer cells (4T1) is confirmed by transmission electron microscopy. Cytotoxicity studies demonstrate that at this concentration the cells are viable.