Theranostic Potential of Metal–Organic Framework/Polydopamine-Modified Magnetic Nanoparticles for Photothermal/Chemotherapy and MR Imaging

Theranostic nanoparticles that integrate therapeutic and diagnostic functions in one system offer significant potential for cancer treatment. The present study aimed to develop a theranostic hybrid nanosystem based on cobalt ferrite (CFO), polydopamine (PDA), and UiO-66-NH₂ (UiO) metal organic framework, to be used for magnetic resonance imaging (MRI) applications and synergistic photothermal therapy (PTT)/chemotherapy. Material characterizations confirmed that a nanostructure with a mean diameter of less than 100 nm has been successfully constructed. Due to the CFO component, the CFO@PDA@UiO demonstrated a relaxivity of 101.3 mM^-1. s^-1, showing potential as a T₂-weighted contrast agent. PDA improved the photothermal conversion capability of the CFO@PDA@UiO hybrid nanosystem, increasing the medium temperature within the hyperthermia therapy range. The UiO shell also acted as a carrier for the anticancer drug Gemcitabine (GEM). Ultraviolet-visible (UV-vis) spectroscopy analysis estimated that nanoparticles have a loading capacity of about 17.59% and approximately 30% of GEM was released at acidic pH (5.5). Drug-loaded nanoparticles demonstrated excellent hemocompatibility, with less than 5% hemolysis at concentrations up to 500 μg/mL. Compared to the free GEM, CFO@PDA@UiO-GEM exhibited more effective anticancer activity against MCF-7 cancer cells under NIR laser irradiation. As a result, the synthesized CFO@PDA@UiO hybrid nanosystem showed great potential as a candidate for cancer theranostic applications.