Determination of Protein Absorption Profile at the Surface of Biocompatible Superparamagnetic Iron Oxide Nanoparticles Using Gel Electrophoresis

Superparamagnetic Iron Oxide NPs (SPIONs), because of their multi-task capabilities, (e.g. magnetic labeling, cell isolation, hyperthermia, and controlled drug release) have been recognized as one of the most promising NPs for theranostic applications. When NPs come in contact with a biological medium, the surfaces of them are covered by biomolecules (e.g., proteins, natural organic materials, and enzymes). Therefore, what a biological entity, such as cells, tissues, and organs, sees when interacting with NPs is the different original pristine surface of the NPs and actually is hard protein corona. The shape of NPs has a great impact on proteins adsorb onto its surface and consequently on the way that cells interact with it. In this research, goethite (α-FeOOH) nanorods have been synthesized using homogenous co-precipitation of Fe2+ and Fe3+ ions using slow hydrolysis of urea at 90 °C. It is revealed that urea plays a crucial role not only as a base source but also as a soft template to form α-FeOOH nanorods. Cytotoxicity of nanorods was assessed using the MTT assay, which is a nonradioactive, colorimetric assay. The cell-SPION incubation time was selected 4, 8 and 48 h. According to the results, the biocompatibility of the polyethylene glycol coated particles is higher than bare. Influence of shape and aspect ratio of as-synthesis NPs in protein absorption profile on the surface of them has been investigated. One-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1D SDS-PAGE) was used for separation of Fetal Bovine Serum (FBS) proteins absorbed onto NPs and demonstration of the shape and aspect ratio influences.