Synthesis and catalytic evaluation of Fe3O4/MWCNTs nanozyme as recyclable peroxidase mimetics: Biochemical and physicochemical characterization

In this research, the nanocomposite of multiwalled carbon nanotubes and magnetic metal oxide nanoparticles (Fe3O4/MWCNTs), as enzyme mimetic, was synthesized using an in situ chemical reduction method. The structure, composition and morphology of the prepared Fe3O4/MWCNT nanocomposite materials were characterized using X-ray diffraction, FT-IR and scanning electron microscopy with energy dispersive X-ray spectroscopy, respectively. The magnetic properties of the nanocomposite were investigated by the vibrating sample magnetometer. A colorimetric system involving nanozyme, phenol/4-aminoantipyrine and H2O2 was utilized for the determination of peroxidase mimetic catalytic assay. The obtained results confirmed that the synthesis of Fe3O4/MWCNTs nanostructures was successful. It was found that Fe3O4/MWCNTs nanohybrid exhibited peroxidase-like activity without any pH limitation. Colorimetric data demonstrated that the prepared nanocatalyst had higher catalytic activity toward H2O2 than MWCNTs. The kinetic parameters of the nanozyme, K-m and V-max, were estimated to be 8.3mm and 1.4mmmin(-1), respectively. The Fe3O4/MWCNTs nanostructures were also successfully applied for glucose detection. In addition, peroxidase-like activity of the nanozyme increased in the presence of butyl-imidazolium bromide ionic liquid. These biomimetic catalysts have some advantages, such as simplicity, stability, reusability and cost effectiveness, which makes them great candidates to be used in various fields of biotechnology applications.