Well Defined Poly(Methyl Methacrylate)-Fe₃O₄/Poly(Vinyl Pivalate) Core-Shell Superparamagnetic Nanoparticles: Design and Evaluation of In Vitro Cytotoxicity Activity Against Cancer Cells

The objective of this work is to develop and characterize polymeric nanoparticles with core-shell morphology through miniemulsion polymerization combined with seeded emulsion polymerization, aiming at the application in the treatment of vascular tumors via intravascular embolization. The synthesis of the core-shell nanocomposites was divided into two main steps: (i) Formation of the core structure, consisting of poly(methyl methacrylate)/magnetic oxide coated with oleic acid (OM-OA) via miniemulsion and (ii) shell structure produced through seeded emulsion polymerization of vinyl pivalate. Nanocomposites containing about 8 wt.% of OM-OA showed high colloidal stability, mean diameter of 216.8 nm, spherical morphology, saturation magnetization (M_s) of 4.65 emu·g^-1 (57.41 emu·g^-1 of Fe₃O₄), preserved superparamagnetic behavior and glass transition temperature (T_g) of 111.8 °C. TEM micrographs confirmed the obtaining of uniformly dispersed magnetic nanoparticles in the PMMA and that the core-shell structure was obtained by seeded emulsion with M_s of 1.35 emu·g^-1 (56.25 emu·g^-1 of Fe₃O₄) and T_g of 114.7 °C. In vitro cytotoxicity assays against murine tumor of melanoma (B16F10) and human Keratinocytes (HaCaT) cell lines were carried out showing that the core-shell magnetic polymeric materials (a core, consisting of poly(methyl methacrylate)/Fe₃O₄ and, a shell, formed by poly(vinyl pivalate)) presented high cell viabilities for both murine melanoma tumor cell lines, B16F10, and human keratinocyte cells, HaCaT.