It is obvious that the development of core–shell particles combining superparamagnetic core and plasmonic shell is attractive and opens a broad area of potential applications. In the current article, the “green” method for the preparation of stable Fe3O4 core Agshell nanoparticles (NPs) with the use of essential amino acid tryptophan is proposed. During Ag+ reduction of the surface of Fe3O4 NPs, tryptophan acts as a reducing and stabilizing agent. Consequently, the mixture of plasmonic NPs is formed, namely, small individual Ag NPs and complex core–shell Fe3O4 core Agshell composites having superparamagnetic core. Colloidal solutions exhibit absorption in the visible range of spectra near 420 nm that corresponds to localized surface plasmon resonance of silver. After the separation with magnetic field, Fe3O4 core Agshell NPs (the average size of 40–60 nm) have plasmon resonance band at max = 424 nm, indicating the formation of Ag shell on the magnetite surface. Obtained colloids were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), zeta-potential, and UV–Vis spectroscopy. According to the model in vitro test on skin fibroblast line BT5ta, more than 70% of cells were found to be viable relative to the control, during 24 h of incubation with NPs.
Pylypchuk, I. V., Mukha, I. P., Vityuk, N. V., Szczepanowicz, K., Storozhuk, L. P., Eremenko, A. M., … Gorbyk, P. P. (2019). Tryptophan-Stabilized Plasmonic Fe3O4/Ag Nanoparticles. In Springer Proceedings in Physics (Vol. 222, pp. 417–430). Springer Science and Business Media, LLC. https://doi.org/10.1007/978-3-030-17755-3_28