Magnetite nanoparticles decorated porous reduced graphene oxide for bio- and medical application

Green chemistry is an innovative and growing field in the search for more environmentally friendly processes. Herein, using an organic green source (an extract of Thymus kotschyanus), we constructed nanocomposites, which are composed of magnetic constituents (Fe3O4 nanoparticles) and carbon materials and exhibit excellent antioxidant, antibacterial, and anticancer activity. The nanocomposite is shown to consist of spherical Fe3O4 nanoparticles of 37–44 nm in diameter on sheets of porous reduced graphene oxide (prGO). The total phenol concentration in the nanocomposite based on prGO (Fe3O4–prGO) was 0.72 ppm according to measurements with the use of Folin—Ciocalteau reagent. Antiradical activity with respect to 2,2-diphenyl-1-picrylhydrazyl (DPPH) was 80.84%. Also, Fe3O4—prGO exhibited a strong antimicrobial activity against bacterial species, especially, against gram-positive bacteria (Staphylococcus aureus) as compared to gram-negative bacteria (Escherichia coli). Moreover, the evaluation of Fe3O4—prGO cytotoxicity carried out on human colorectal adenocarcinoma cell line HT-29 showed a significant toxicity of the nanocomposite towards HT-29 cells (with cell viability of 19.0% and 12% after 24 and 48 h of exposure to Fe3O4—prGO at a concentration of 200 µg mL−1). Due to surface functionalization with Thymus kotschyanus extract phytomolecules and the addition of Fe3O4 nanoparticles, Fe3O4—prGO can be considered as a potential anti-oxidant, anticancer, and antibacterial agent and can be used in medicine.