Highly Stable and Selective Non-Enzymatic Glucose Biosensor Using Carbon Nanotubes Decorated by Fe₃O₄Nanoparticles

Novel enzyme-free and direct electrochemical glucose biosensors, using glassy carbon electrode modified by iron oxide nanoparticles-decorated MWCNTs are fabricated. The MWCNTs were synthesized by catalytic chemical vapor deposition using ferrocene as a floating catalyst and functionalized in HNO 3 . The morphology and structure of the samples were characterized with transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR). The electrocatalytic activity of the modified electrode toward glucose oxidation was evaluated by cyclic voltammetery and amprometry in 0.05 M phosphate buffer solution at pH 7.0. The results show that the functionalized MWCNTs significantly enhance the catalytic behavior of Fe 3 O 4 for glucose oxidation. The direct electron transfer coefficient between the electrode surface and glucose is 0.35. The prepared electrode shows a linear behavior in the range of 0.5–7.0 mM with a high sensitivity of 238.7 μA mM −1 cm −2 and a low detection limit of 15.0 μM at S/N = 3.0. The glucose biosensor exhibits reproducible response, long-term stability, as well as no interference from ascorbic and uric acids.