Iron–gold nanoflowers: A promising tool for multimodal imaging and hyperthermia therapy

This article belongs to the Special Issue Recent Advances in Metallic Nanoparticles as Theranostics Platforms.
The development of nanoplatforms prepared to perform both multimodal imaging and combined therapies in a single entity is a fast-growing field. These systems are able to improve diagnostic accuracy and therapy success. Multicomponent Nanoparticles (MCNPs), composed of iron oxide and gold, offer new opportunities for Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) diagnosis, as well as combined therapies based on Magnetic Hyperthermia (MH) and Photothermal Therapy (PT). In this work, we describe a new seed-assisted method for the synthesis of Au@Fe Nanoparticles (NPs) with a flower-like structure. For biomedical purposes, Au@Fe NPs were functionalized with a PEGylated ligand, leading to high colloidal stability. Moreover, the as-obtained Au@Fe-PEG NPs exhibited excellent features as both MRI and CT Contrast Agents (CAs), with high r2 relaxivity (60.5 mM−1⋅s−1) and X-ray attenuation properties (8.8 HU mM−1⋅HU). In addition, these nanoflowers presented considerable energy-to-heat conversion under both Alternating Magnetic Fields (AMFs) (∆T ≈ 2.5 °C) and Near-Infrared (NIR) light (∆T ≈ 17 °C). Finally, Au@Fe-PEG NPs exhibited very low cytotoxicity, confirming their potential for theranostics applications
Financial support was provided the Ministerio de Economía, Industria y Competitividad (CTQ2017-86655-R), Ministerio de Ciencia e Innovación (PID2020-118448RB-C21, PID2020-113108RB-I00 (funded by MCIN/AEI/10.13039/50110001103), and PGC2018-096016-B-I00, the Fondo Social de la DGA (grupos DGA)), and by the Regional Ministry of Health of Andalusia (OH-0026-2018 and PAIDI 2020. P20_00727).