Magnetic–Plasmonic Nanoscale Liposomes with Tunable Optical and Magnetic Properties for Combined Multimodal Imaging and Drug Delivery

Magnetic–plasmonic nanoparticles (NPs) have shown remarkable potential in hyperthermia, magnetic resonance imaging, and surface-enhanced Raman scattering imaging and diagnostics. However, despite their promise, effective clinical translation remains limited due to a lack of fundamental knowledge about the biological response to these materials, and ongoing efforts seek to bridge the gap between nanomaterial design and effective applicability. To overcome these hurdles, the combination of inorganic NPs with lipid membranes has emerged as an attractive strategy for the biocompatibilization of nanomaterials, preserving the inherent properties of each component and exhibiting synergistic functionalities. This study explores the structural and dynamic aspects of magnetic–plasmonic liposomes produced via spontaneous self-assembly of Au–Fe 3 O 4 NPs and synthetic liposomes, as a function of the lipid vesicles’ composition and concentration. By combining cryogenic electron microscopy, ultraviolet-visible spectroscopy, and dynamic light scattering, we demonstrated that the bending rigidity and fluidity of the lipid membrane control the aggregation of the NPs on the membrane and the colloidal stability of the hybrids. The experimental results demonstrate that the coexistence of 10 nm Fe 3 O 4 magnetic seeds and 50 nm Au–Fe 3 O 4 NPs plays a crucial role in the assembly of lipid-NP magnetic–plasmonic hybrids. This thermodynamic control allows for fine adjustment of the hybrids’ size and composition, thereby allowing for enhancement and tuning of the magnetic response. Overall, these results pave the way for the development of multifunctional nanomaterials with controlled magnetic–plasmonic properties, obtained via spontaneous self-assembly, as combined nanoprobes and nanovectors for potential applications in multimodal imaging and drug delivery.