In situ reduction of Ag on magnetic nanoparticles with gallic acid: effect of the synthesis parameters on morphology

Plain language summary Nanoparticles (NPs) have been extensively investigated in the biomedical field for their use in diagnosing and treating tumors. The aim of this work was to develop a simple and green method to produce NPs formed from iron oxides (which are magnetic) and silver. Magnetic NPs can be moved utilizing an external magnetic field, which can be used to localize NPs in a particular location, such as in tumors. Silver NPs have antibacterial properties and can be used to generate heat to kill tumor cells when exposed to light. This study showed that, by varying factors when synthesizing these NPs (e.g., amount of reagents, presence of coatings on the particles), it is possible to obtain multifunctional NPs with different shapes and sizes.Aim: Synthesis of Fe3O4-Ag composite nanoparticles (NPs) by a new in situ reduction of Ag NPs on the surface of Fe3O4 NPs using gallic acid as a reducing agent. Materials & methods: The influence of process parameters on NP morphology and functionalization was evaluated by means of field-emission scanning/scanning transmission electron microscopy and Fourier-transform IR spectroscopy. Results & conclusion: The synthesis conditions affected the morphology of the obtained NPs, evidence of the formation of polydispersed aggregates, nanoflower-like or nanodumbbell nanocomposites. In particular, well-defined nanodumbbells were obtained in aqueous media, with an NP/gallic acid ratio of 10:1, while the presence of a silica shell did not improve the morphology of Ag NPs nucleated on the Fe3O4 core.