Fe ₃ O ₄ /ZIF-8-90 Nanocomposite as a Strategy for Oncological Treatment

Cancer is one of the leading causes of mortality worldwide, and traditional treatments, such as systemic chemotherapy, often have side effects due to their lack of specificity. This limitation has driven the search for new, more selective, and effective therapeutic strategies. In this context, this study proposes the development of a magnetic nanocarrier with superparamagnetic iron oxide nanoparticles (SPIONs) associated with the metal-organic framework ZIF-8-90, forming the Fe₃O₄/ZIF-8-90 nanosystem. The synthesized nanocarrier showed a uniform size distribution, with an average diameter of 97 nm, and could adsorb approximately 13% of the 5-FU load. Fe₃O₄/ZIF-8-90 exhibited significant biocompatibility for healthy cells (Vero strain), maintaining 85% cell viability at concentrations of up to 100 μg/mL. In contrast, it showed selective cytotoxicity against breast (MDA-MB-231) and lung (H292) tumor cells. As for its therapeutic potential through application in magnetic hyperthermia, the nanomaterial raised the temperature by up to 5.2 °C in just 10 min, using field amplitude and frequency below the biologically safe limits. In addition, relaxometric characterization also pointed to Fe₃O₄/ZIF-8-90 as a promising contrast agent for MRI in T₂ mode, achieving an r ₂ relaxivity of 180.15 mM^-1 s^-1. These results consolidate the synthesized Fe₃O₄/ZIF-8-90 nanocarrier as a promising theranostic platform, combining therapeutic efficacy and diagnostic functionality for oncological applications.