Chitosan‐Coated Green‐Synthesized Magnetic Fe ₃ O ₄ Nanoparticles as Smart Carriers for pH‐Triggered Doxorubicin Release in Cancer Treatment

ABSTRACT Breast cancer remains one of the most lethal and challenging malignancies affecting women worldwide. Despite decades of research, the search for effective therapeutic strategies is still ongoing. Nanomedicine has emerged as a promising field, offering versatile platforms for targeted drug delivery. In this study, we report the biogenic synthesis of magnetic iron oxide nanoparticles (Fe 3 O 4 NPs) using Moringa oleifera leaf extract as a natural reducing and stabilizing agent. The synthesized Fe 3 O 4 NPs were subsequently functionalized with chitosan (CS) to obtain Fe 3 O 4 @CS NPs, which were further loaded with doxorubicin (DOX) to form Fe 3 O 4 @CS‐DOX‐NPs for breast cancer therapy. These nanoparticles were successfully synthesized and characterized by spectroscopic and microscopic techniques. The Fe 3 O 4 @CS‐DOX NPs displayed high drug encapsulation efficiency and exhibited pH‐responsive release behavior, with enhanced DOX release under acidic conditions (pH 5.4) due to protonation of CS amine groups. Moreover, they demonstrated significant cytotoxicity against Michigan Cancer Foundation‐7 (MCF‐7) human breast cancer cells, with an IC 50 value of 9.2 µg/mL, alongside strong anti‐inflammatory activity (IC 50 = 8.15 µg/mL). These findings suggest that Fe 3 O 4 @CS‐DOX‐NPs are a promising nanoplatform for breast cancer treatment and warrant further in vivo evaluation.