Encapsulation of magnetic nanoparticles in poly(methyl methacrylate) by miniemulsion and evaluation of hyperthermia in U87MG cells

• Magnetic nanoparticles (MNPs) were encapsulated by MMA miniemulsion polymerization.
• Stable and monomodal MNPs-PMMA dispersion in aqueous medium was obtained.
• MNPs-PMMA nanoparticles presented superparamagnetic properties.
• Biocompatibility assays show that MNPs-PMMA are suitable for biomedical applications.
• MNPs-PMMA showed a high efficiency in hyperthermia therapy on U87MG cells.

Magnetic nanoparticles (MNPs) are promising materials for hyperthermia treatment and magnetic targeting systems. The objective of this work was to synthesize and characterize magnetic nanoparticles coated with oleic acid (MNPsOA) loaded with poly(methyl methacrylate) prepared by miniemulsion polymerization (MNPs-PMMA) and evaluate their cytotoxicity in murine fibroblast (L929) cells, blood biocompatibility (hemolysis assay) and hyperthermia (HPT) in human glioblastoma (U87MG) cells. The MNPs-PMMA nanoparticles presented average mean diameter of 99 ± 1.9 nm with a polydispersity index (PdI) of 0.13 ± 0.15 and saturation magnetization (Ms) value of 34 emu/g of iron oxide, as well as superparamagnetic proprieties. The MNPs-PMMA nanoparticles did not present cytotoxicity in murine fibroblast (L929) and U87MG cells. HPT assays were applied, demonstrating that AC magnetic field application (1 MHz and 40 Oe) for 3 min or 6 min reduced the viability cells by 75% and 52% respectively. Morphological analyses showed that U87MG cells treated with 0.1 μg mL−1 of MNPs-PMMA nanoparticles shrank after AC magnetic field application for 6 min, resulting in a region of hypoxia. Hemolysis assay showed that MNPs-PMMA nanoparticles presented high blood biocompatibility. Our results indicate that MNPs-PMMA nanoparticles obtained by miniemulsion polymerization have the potential to be used as carrier systems for HPT.

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