from the conferences organized by TANGER Ltd.
In the search for a suitable and biocompatible material with high photothermal efficacy for hyperthermic application in nanomedicine, gold (Au) nanocolloid solutions with a surface plasmon resonance located in the near-infrared spectral region were prepared using a one-step environmentally friendly phytosynthetic process. The room-temperature process involves a liquid extract of Mentha × piperita leaves and Au(III) aqueous solutions, and no additional reagents or surfactants are required. The one-step green process yields Au nanocolloid solutions that are stable for weeks. UV-Vis spectroscopy measurements of the obtained Au nanocolloid solutions show that the position of the near-infrared surface plasmon resonance maximum can be controlled by the synthetic conditions in the range of 720-1100 nm. Transition electron microscopy shows that irregularly shaped Au nanoparticles (Au-NPs), in the form of triangles and hexagons, are phytosynthesized together with regular (spherical) Au-NPs in varying ratios. These ratios depend on the composition of the mixture used and the phytosynthesis conditions. When plasmonic Au nanocolloid solutions are exposed to laser light at wavelengths of 808, 850 and 980 nm, they produce a reliable and consistent photothermal response without any photoinduced decay. The optical properties and potential biocompatibility of the gold nanocolloids make them promising for hyperthermia or bioimaging.
Keywords: Peppermint, gold nanoparticles, green synthesis, surface plasmon resonance, photothermia© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.