Galvanic Replacement as a Synthetic Tool for the Construction of Anisotropic Magnetoplasmonic Nanocomposites with Synergistic Phototransducing and Magnetic Properties

Magnetoplasmonic nanomaterials, which combine light and magnetic field responsiveness in an advantageous manner, are attractive candidates for bio-nanoapplications. However, the synthetic access to such hybrid particles has been limited by the incompatibility of the iron- and gold-based lattices. In this work, we provide the first insights into a new synthetic strategy for developing magnetoplasmonic anisotropic nanocomposites with prominent phototransducing properties. In our approach, magnetic nanocubes based on an alloy of iron oxide, zinc, and silver were constructed. In a key second stage, the galvanic replacement of silver with gold atoms yielded satellite-like magnetoplasmonic anisotropic structures. Superior magnetic and photoconverting properties were observed for the novel magnetoplasmonic nanocomposites when compared with the pure parent structures. Moreover, the synergy between the magnetic and optical stimuli was examined, showing shape-dependent contributions in the magnetization experiments. More importantly, an excellent cell ablation capability upon laser irradiation was observed for the magnetoplasmonic nanocomposites compared to the pure magnetic or plasmonic controls. Further demonstration of these novel theragnostic agents as MRI contrast agents is also reported even during the light-irradiation event. Thus, the described particles showed promising properties for bioapplications emerging from the novel synthetic methodology.