Magnetic graphene-based ferrite nanoparticles: synthesis, characterization, and anti-proliferative activity against...

This work introduces a novel soft magnetic building block (GCM), based on reduced graphene oxide covalently functionalized with Congo red molecules and incorporated with barium ferrite nanoparticles, creating a promising multifunctional platform for future magnetically controlled nanorobotic systems for potential cancer therapy and diagnosis nanodevices. The sol-gel auto-combustion method was used for the synthesis of pure barium ferrite (M) and in situ synthesis of reduced graphene oxide-barium ferrite nanoconjugate (GM). Physicochemical characterization techniques were used for identification, including infrared spectroscopy, X-ray diffraction, UV-visible spectroscopy, thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, vibrating sample magnetometry, size distribution analysis, and ζ-potential analysis. M showed hard ferrimagnetic properties with a coercivity (H _c) of 2183 Oe, while GCM and GM demonstrated soft ferrimagnetic character with H _c values of 212 Oe and 147 Oe, respectively. Barium ferrite demonstrated higher saturation magnetization (M _s) than both GCM and GM. M _s values of 59 emu g^-1, 35 emu g^-1, and 25 emu g^-1 were recorded for M, GCM, and GM, respectively. The decreased saturation magnetization is attributed to spin disorder due to the presence of graphene domains with defects and different functional groups on the GCM and GM surfaces. MTT assays revealed that the barium ferrite graphene derivatives (GM/GCM) exhibited potent antiproliferative activity against both human colon cancer (HCT116) and human breast cancer cells (MCF-7), without affecting normal cells, with an IC₅₀ range of 22.5-37 µg mL^-1. DNA fragmentation assays indicated that the graphene surface attached to Congo red molecules (GC/GCM) has a high activity for inducing DNA damage. Further insights into the mechanism of the apoptotic effect revealed that apoptosis was exerted via the intrinsic caspase-dependent pathway. Additionally, Congo red functionalization (GCM) further improved targeting specificity without compromising safety. qRT-PCR analysis demonstrated the upregulation of caspase-3, Bax, and p53. At the same time, downregulation of Bcl-2 was observed, confirming the enhanced apoptotic pathways in both cancer cell lines. The results were further supported using in silico studies, which showed high-affinity binding to the CD45 protein, with the strongest docking score (-22.92 kcal mol^-1) for GC.