Magnetic iron-based nanoparticles encapsulated in graphene/reduced graphene oxide: Synthesis, functionalization and cytotoxicity tests

Nanomaterials for suitable particle sizes, shapes, surface properties, biocompatibility, magnetic properties, and chemical stability are candidates for biomedical applications. Among these nanomaterials, iron-based ones are highly interested in their morphological and magnetic properties for potential utilizations in biomedicine. However, iron-based nanoparticles lose their chemical stability in body fluids because of their oxide formations and transformations. Their use in biomedical applications, especially in imaging, may be less effective if they are oxidized and have lower magnetization values. Thus, the idea of coating them with a protective layer has recently emerged to prevent magnetic nanoparticles from degrading in human fluids and losing their magnetic properties. However, the biological effects of these coated nanoparticles on human cells are poorly understood. In this paper, the synthesis of multilayer graphene (MLG) encapsulated iron-based nanoparticles was investigated by solvothermal and chemical vapor deposition (CVD) methods followed by purification. Subsequently, their surface modification was conducted with pyrene end-functional POEGMA obtained by atom transfer radical polymerization (ATRP). Cytotoxicities of synthesized nanoparticles were evaluated in MCF7 cell lines, which is a commonly used model for breast cancer research. We also compare the results with those obtained from bare iron oxide nanoparticles (IONPs) and iron oxides that were embedded in reduced graphene oxide (rGO) or partially coated with it. We aim to evaluate the safety and efficiency of these nanoparticles and increase their chemical stability as a multifunctional nano platform for cancer diagnosis and treatment. Characterization techniques such as XRD, XPS, SEM, TEM, DTA/TG, DLS, zeta potential, BET, NMR, FTIR, and VSM were performed on the nanoparticles. Cytotoxicity assessments on MCF-7 cell lines indicated the potential of these graphene-based magnetic nanoparticles for biomedical applications, particularly drug delivery, due to their small size, soft ferromagnetic properties, high chemical stability, and cytocompatibility at concentrations below 500 μg/mL over short incubation times.