Core–Shell Plasmonic Nanostructures for Hyperthermia of Cancer and Tumor Cells

Plasmonic nanostructures continue to be the most promising alternative to hyperthermia treatment of cancer or tumors by focusing the light locally. Absorption and scattering cross-sections of 48 nanorods encompassing silver and palladium as core and gold and platinum as coating with four different aspect ratios and three different coating thicknesses were examined in an aqueous solution with finite-element method (FEM). According to the highest value of photothermal conversion efficiency (PCE) in each bimetallic compound, three Au@Ag, Pt@Ag, and Au@Pd nanorods, with aspect ratios of 4, 4, and 5, respectively; and all with a coating thickness of 1 nm; were chosen as the best ones named “A,” “B,” and “C”. Each nanorod irradiated by continuous wave (CW) laser radiation with 1 mW·μm⁻² intensity at the LSPR wavelength for 200 ns, the temperature of the nanorods increased from 37 to 82.6, 46.34, and 44.33 °C, respectively. To robustly control the temperature in time and locally, the irradiation intensity of the “A” was decreased to 0.5 mW·μm⁻², that its ambient temperature increased by 45 °C at a distance of 20 nm, which can selectively cause irreparable damage to the cancer cells. In addition, the nanorods were irradiated by pulsed laser for 200 ns periods. The results show that the bimetallic nanoparticles can convert light into heat locally.

Graphical Abstract