Cancer cell membrane-coated superparamagnetic iron oxide nanoparticles as a theranostic platform for magnetic...

Superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as promising theranostic agents owing to their magnetic hyperthermia efficiency and capability as magnetic resonance imaging (MRI) contrast agents. However, achieving sufficient intracellular iron accumulation remains a critical challenge for effective therapy. In this study, we report the development of cancer cell membrane-coated SPIONs (CM-SPIONs) to enhance tumor targeting and intracellular delivery. The CM-SPIONs were prepared using a modified Bangham method in the presence of membranes derived from 4T1 triple-negative breast cancer cells. The resulting nanoparticles exhibited significantly enhanced cellular uptake, reaching an intracellular iron concentration of 6 μg [Fe]/10⁶ cells after 24 h incubation, representing a fivefold increase compared to uncoated SPIONs. Fluorescence imaging revealed predominant localization within lysosomes in the perinuclear region, suggesting that the lysosomal compartment may contribute to the observed AMF-induced cytotoxicity. Upon exposure to an alternating magnetic field (AMF) for 45 min, the CM-SPIONs resulted in 78.6% inhibition of cell proliferation, which was markedly higher than uncoated SPIONs. Furthermore, incubation with CM-SPIONs (0.05 mg [Fe]/mL, 3 h) reduced the T₂ relaxation time from 2.71 s in the untreated cell suspension to 0.48 s, demonstrating significant MRI contrast enhancement. These results indicate that the CM-SPIONs represent a promising platform integrating magnetic hyperthermia with MRI-based cancer theranostics.