Development of hybrid silver nanosystems and paramagnetic complexes for theranostic applications in photothermal therapy and magnetic resonance.

Theranostic nanomaterials are increasingly relevant in cancer research, as they integrate diagnosis and therapy into a single platform, enabling precise detection and efficient treatment with reduced invasiveness. Magnetic resonance imaging (MRI) is valuable due to its high spatial resolution and non-invasive nature, while plasmonic photothermal therapy converts light into localized heat to damage diseased cells while preserving healthy tissues. Silver nanoparticles (AgNPs) are attractive photothermal agents due to their strong localized surface plasmon resonance, simple synthesis, tunable size and morphology, low cost, and functionalizable surfaces. In this study, AgNPs were conjugated with Gd³⁺ chelates to obtain multifunctional theranostic nanoplatforms combining photothermal performance and MRI contrast capabilities. The systems exhibited excellent colloidal stability, suitable plasmonic bands, relaxivity values ​​comparable to those of clinical MRI contrast agents, and a temperature increase upon 808 nm laser irradiation, demonstrating their potential for photothermal therapy and MRI.