Image-Guided Dual Magnetic-Photothermal Hyperthermia Using a Multifunctional Fe₃O₄-PANI-GQD Biomaterial Platform

Triple-negative breast cancer (TNBC) remains a therapeutic challenge owing to the lack of molecular targets and high recurrence rates. Here, we report a multifunctional magneto-photothermal nanoplatform (FPG), engineered from a magnetic Fe₃O₄ core, a near infrared (NIR)-active polyaniline shell, and fluorescent graphene quantum dots for image-guided combined hyperthermia. FPG demonstrated superior colloidal stability, retained superparamagnetism, and exhibited strong NIR absorption. Upon exposure to an alternating magnetic field (AMF) and 808 nm laser irradiation, FPG consistently raised suspension temperatures within the therapeutic hyperthermia range under in vitro conditions. The nanoplatform induced concentration-dependent cytotoxicity in MDA-MB-231 cells, with significantly enhanced tumor suppression observed under combined AMF and NIR exposure compared to single modality. In vivo, image-guided combined-mode therapy resulted in significant tumor regression with minimal systemic toxicity, as evidenced by histopathology and serum biochemistry. To demonstrate translational feasibility, an integrated AMF-NIR prototype system was developed, enabling synchronized magnetic and optical heating with thermal feedback control. This work highlights how rational interface engineering of multifunctional biomaterials can be leveraged for image-guided hyperthermia and translational cancer therapy.