A magnetic nanoscale Fe₃O₄/Pβ-CD composite as an efficient peroxidase mimetic for glucose detection.

Magnetic polymer particles with different surface functionalizations were prepared by a simple one-pot solvothermal method and characterized as peroxidase mimetics. The fluorescence enhancement obtained by attaching a β-cyclodextrin polymer (Pβ(-CD)) to the surfaces of Fe3O4 magnetic microspheres (Fe3O4 MMs) to generate a Fe3O4/P(β-CD) composite allowed the rapid, sensitive and selective analysis of glucose. The catalytic activity of the Fe3O4/P(β-CD) composite was evaluated with regard to the effects of catalyst particle size and species, pH value, level of catalyst, benzoic acid concentration and reaction time. Detection limits of 0.015 μM for H2O2 and 0.03 μM for glucose were determined when measuring at the 10-min mark. The presence of other saccharides, ion species, amino acids and proteins, had little effect on the results, and this technique was found to allow the analysis of glucose in human serum with high accuracy. The reusability of the Fe3O4/P(β-CD) composite was also investigated after 10 successive runs. A possible mechanism is proposed in which Fe3O4 plays a significant role in inducing fluorescence and P(β-CD) enhances the fluorescence signal, acting as both a stabilizer and a phase transfer agent.